ALtec Model 19-XO upgrade discussion [Archive]

Paul C.

12-13-2006, 09:39 AM

I'm Paul C. that built GaryL's Model 19 crossovers.

Gary sent some Model 15 stripped chassis that are identical but for marking on the faceplate, as well as some new 8 ohm L-pads and knobs.

I have the Model 19 schematic so, it was time to order parts.

Inductors... I got a Jantzen .33 mH 15 ga aircore to use for the .3 mH, and a .8 mH 18 ga aircore to use for the .77 mH specified in the schematic. These differences in values are so small as to be inaudible.

Since the .33 mH was to be in series with the woofer, the 15 ga was chosen so as to have minimal resistance. The .8 mH (or .77 mH) inductor is a shunt to ground in the HF section, and the resistance is not a real factor in performce.

For large inductors, anything from 1.0 mH on up, I use iron core inductors. They are smaller, use less wire, and have less resistance than the same value in an air core. Plus they are cheaper, only 1/2 or 1/3 as much. The problem of "saturation" of iron core inductors only happens at power levels of hundreds of watts, and even then, only momentarily. At those volume levels "high fidelity" is not a priority, and even then, unlikely to be noticed. Besides, the originals are iron core, or "transformer" type inductors. Iron core is the practical choice here.

Caps used are Dayton polys. For very larger values I usually use electrolytics, but none were needed here. Again, I made a few value substitutions. 8.2 uf was used where the 8.0 uf was specified, and 6.2 uf was used where the 6.0 uf was specified. These are certainly close enough. Also, 4 ohm resistors were used for the specified 3.9 ohm resistors, and "close enough for jazz".

The large iron core 2.7 mH inductor was screwed to the chassis. The two aircore inductors were strapped to the chassis with Ty-Wraps, as well as being stabilized with blobs of glue so they would not vibrate. They were oriented to minimize crosstalk.

The caps and resistors were glued to the chassis and to each other. Hot melt glue is not used, it may damage capacitors and does not stick well to metal. I use a glue I have found to be perfect for this use, E6000 by Eclectic Products. There is a similar glue, a little more solvent so it is thinner, called Aleene's Platinum Bond 7800 that works well, too. These glues can be found in hardware, hobby, and craft stores. I get them at Walmart in crafts. These glues are "SBR adhesives", that is, Styrene Butadyene Rubber adhesive. They dry clear, and are very slightly rubbery. They do not give off acetic acid like some silicones. They are flexible when dry but much firmer than silicone. I keep both E6000 and 7800 in my shop and go through at least a tube a week. Great for gluing dissimilar materials, and sticks well to metal, too.

4313B

12-13-2006, 09:41 AM

Very nice! :)

Gary L

12-13-2006, 10:07 AM

Thanks Paul, very informative.
I have read many threads regarding guys who tried different Caps and coils with terrible results.
Not understanding the electronics behind these results or the reasons why one brand of cap or type of coil produces poor sound is one of the reasons I started this thread.
To those of us who are not up to speed on this tech stuff it is very difficult to understand why a Poly cap may or may not work or why an iron core sounds different from an air coil. Even harder to understand why one brand of Poly cap with an X value would sound different from another brand of Poly cap with the same X value.

Then there is always plenty of discussion on the best Hz to run 19s on.
Some swear by the 800Hz while others claim the stock 1200Hz is best.

Others here have completely done away with the adjustment L pads and like that better.

I know Dave Wojo rolls his own XOs and is very happy with the changes he makes and others have discussed in many threads other types of crossovers, maybe ACTIVE, if I remember correctly. Still others claim that bi amping is the way to go with 19s.

Talk about confusing!

It sure would be nice to get a grocery list of upgrades and what results have been found.

I am a sort of purist in that I prefer 19s to sound just like 19s the way they came from the factory. Replacing caps with ones that work right is easy and relatively inexpensive if we know what ones to use.

I have no problem with anyone who wants to completely rework or change any of their XOs to anything they want but I have to say the 19s gained a place in our hearts by simply being 19s and sounding the way they do.
I don't doubt they could sound better with some tweeks but many of us don't have the knowledge, ability or desire to do it.

Gary

Mr. Widget

12-13-2006, 12:20 PM

I have also listen to this passive pair on a friends set of 19's.You might suggest that your friend remove that bolt from the core of that inductor... I doubt that is an aluminum bolt and wing nut... if you must run a bolt through the core of an inductor, use brass.

Placing a steel bolt changes the value (increases) and will easily saturate at higher power levels.

Widget

DaveV

12-13-2006, 12:26 PM

It is confusing Gary. I learned some time ago that different caps can and do alter the sound in electronics. I tried a lot of different caps in an amp rebuild before I found a brand and type that came very close to the sound of the original Sprague "Bumble Bee's" that were in the amp. Preserving the sonics was the only way for me because I choose that particular amp for it's known sonic quality. (Mac 225) Yet some people buy vintage equipment and use "audiophile" parts and "upgrades" that greatly alter the original sonic signature. I should add that I had used the amp for a long time. The original caps were not shot and I had become very familiar with the amps sonic signature. I figured it was a matter of time before the caps were trash so I recapped before a problem like red glowing output tubes showed up. Hard to say if either approach is right or wrong because that argument seems to go on and on in other places. Matter of sonic taste I guess. Then I discovered that different caps do alter the way speakers sound but I'm way more critical of a cap in series with a tweeter as that's where I hear the biggest difference. I got my 19's and they sounded good but somewhat distorted so I replaced the caps with ones I had on hand. I didn't like the results because they sounded very harsh but the distortion was gone. I then ordered a brand and type of cap I happened to use in my Flamencos with good sonic results and they were lots better sounding. Not having had the 19's for years is a draw back because I never heard them with "fresh" factory caps so all I had was the that two week sonic memory of what they sounded like with the aged caps but I seem to be satisfied with the new caps. For ha ha's I replaced the large inductor in series with the woofer with a steel core of low resistance and the bass increased more than I expected plus it seemed to be tighter and more extended downward. After enjoying the increased bass for a few days something started to bother me. The human voice was too chesty and some snap was missing in percussion. I put the original Altec inductors back in the circuits and the bass really diminished but voice sounded more natural and that snap came back. Now I miss the better bass but I don't want that heavy chesty voice and muddy lower mid either. One might say that the woofer was more efficient with the "better" lower resistance inductor but raising the level of HF horn doesn't seem to be the solution because that creates another problem. My experience makes me wonder what other peoples experiences are when changing to "better" inductors. I did a quick reading of the original inductors (supposed 2.7) and as I recall they were both below the 2.7mh shown on the xover schematic so that makes me wonder too. The new ones I used were exactly 2.7mh. Then there's the other two inductors! I have yet to totally remove the original inductors and repeat the readings being sure that my LCR meter is properly zeroed but the fact that the new steel cores made such a huge difference points me in the direction of building proto xovers on the floor in front of each speaker. A full new xover to start then if I don't like the results tryng different inductors and even different values to see what the heck is going on. Has anyone else measured value and resistance of the original inductors?
When I got my Flamencos I had more or less the same experience. I built new xovers with "better" parts but I hated the results. I went back to the original inductors, original wirewound resistor and HF level pot and just used new caps. The sound was so much better so there is something going on that needs further explaination. At least to me.
I guess we all have our own sonic preferrence but it's sure helpful to understand why certain things that seem so straight forward make such big changes and not always for the better.

Dave

Zilch

12-13-2006, 12:27 PM

Is this the subject schematic?

For reference, here's the link to my voltage drive analysis:

http://audioheritage.org/vbulletin/showthread.php?t=12305&page=4

And the CBS Tech Center results are here:

http://www.perfectmarketaudio.com/altec/Altec%2019%20Test%20page%201.pdf

DaveV

12-13-2006, 02:16 PM

Yes that's the xover. I had previously printed that info out and I read it. Now here's a new twist on my experience that makes me feel pretty stupid. At least I admit it. LOL After my last post I played some music and something pretty simple occurred to me. Here's the long story: When using the Flamencos I couldn't live with them without an added tweeter. I figured that would be the case with the Model 19's and it was. Even though the 802-G's have a more extended response and they were just redone at Great Plains,they still fall short of what I like in the way of extended solid highs. Based on the CBS Labs report of the Model 19 I can see why. The HF response drops off too early then like a rock and raising the HF pot to compensate doesn't sound good to me or satisfy me. Running the 8 ohm EV T350's with a simple 2uf cap and 1 ohm resistor is series with them straight from the amp does satisfy me if I turn the HF pot on the xover to the 12 o'clock position, or below optimum. Even though the EV's drop like a rock after 14 or 15KHZ the overlap with the 802's really does open everything up and that was well within the ballpark for me even though it was somewhat bright at times. With all my previous speakers I always had the preamp bass and treble set at + 4db to get what I liked so I assumed that was where it needed to stay. I turned the bass and treble controls to the flat position and played bands on many LP's I have had for years and have heard thru several different speakers I've owned. All I can say is WOW. Everything fell into place so well that I have never heard such extended response, smoothness, clarity, balance and impact from any speaker with flat tone control settings! Seems that replacing the woofer inductor brought the bass up plus it hit the 4db bass boost that wasn't just a boost below 100HZ. Live and learn. Now my 19's sound so darn good they really don't need anything but I know I'll be in there replacing those inductors again. This time I expect that the bass will be "better." I imagine tone control curves play a part in this too and in my case the increased woofer output plus the 4db boost was way too much on the upper woofer response. Guess I never thought I'd have a system that came together so well as to be flat enough without preamp frequency compensation to please me yet not so flat to be boring like some "flat" systems are. Now I wonder if that was my problem with the Flamenco bass and the better inductors? I do know that after that I tried "flat" tone control settings with the Flamenco/EV combo and it didn't sound as good as with the +4 bass and treble boost.

Dave

Zilch

12-13-2006, 02:27 PM

There's other ways to get extended VHF if the horn will support it.

I'll try to borrow an 811B and 802-8G here locally and give it a try.

Others here may have already worked with this....

Earl K

12-13-2006, 03:23 PM

There's other ways to get extended VHF if the horn will support it.

I'll try to borrow an 811B and 802-8G here locally and give it a try.

Others here may have already worked with this...

- Well then,,,,good luck with this .

- A couple of significant hurdles that you'll need to overcome are ;

(i) The 2 relative sensitivities of the drivers ( 802-8G vs the 416-8B or 416-8C ) are closer to each other than any of the typical JBL 2-way systems . ( You'll likely need to limit your design to a 95 db / 1 watt system ). Load resistors can help out here by lowering the woofers efficiency .

(ii) Altecs "8 ohm" compression drivers should actually be considered as 8 ohm loads ( unlike JBLs "8 ohm" types which ought to be considered @ 6 ohms . This 2.5 db difference literally comes off the UHF top ( of what "balance" is ultimately possible from any HF compensation scheme ) .

- ( biamping being my favourite approach to both of these dilemmas ) .

:)

Zilch

12-13-2006, 03:38 PM

Thanks, Earl.

I'm thinking see if the stock horn/driver will "push" to, say, 16+ kHz like 4430, with usable vertical beamwidth, or,

Use an alternative driver requiring less compensation to get there and above.

HERESY! Tangerine RULEZ!

[WAIT! That's Klipsch.... :p ]

DaveV

12-13-2006, 04:25 PM

Zilch,

I'm not at all unhappy with the added EV tweeters. I consider them to be one of the best tweeters ever made and after hearing the T350's I could never be happy with T35's again. There's a reason why they go for $800 and upward for a pair on E-Bay. The Altec 3000's I have are great sounding too but the efficiency is too low in this case. I'm not caught up in any guilt about tampering with Altec's design philosophy to do a 2 way that does it all. It clearly does do it all in more than one system for lots of people, but not me. And I feel that having a tweeter sitting on top of the cabinets and connected directly to the amp in no way violates the 19's integrity or value. Just the sound and if it sounds better to me then that's better than dismissing the speakers/drivers because they have limited or weak highs. As I stated before, I've never heard a speaker that does what these do so that says a lot about Altecs design choice for the 19's. I just don't agree with their view on the upper treble. Bozak had the same thoughts with soft treble tweeters and people think they are great too but I never cared for them. The overall smoothness even with the added tweeter, the ability to maintain impact/detail with smoothness, the extended and smooth bass, and the clarity is something most speakers just don't offer and I've heard lots of speakers. Perfect they aren't but no speaker is perfect. They're just closer to perfect than I've ever had before. But even if it were possible to get more extended highs from the 802-8G/811B, would they sound the same and disperse the same as from the smaller horn of the EV T350? I remember EV had a way to extend the highs of their 1823M driver with the addition of a small passive network. My goal has always been to have great sounding vintage tube stereo system with vintage or near vintage speakers using little to no EQ and not a transistor to be seen. TA DAH!

Earl,
I get the whole bi-amp thing but I'm not willing to go that route anymore. My old Bozak 4000's were lots better with a simple bi-amp setup but I've never been able to get those same results with other speakers I've owned because of blend, shelving or overlap problems. I'm just not into 18 or 24db/octave xovers, SS xover networks or expensive tube xover networks. I think I would be spinning my wheels and spending lots of time and money to get back to where I am now with the overall smoothness although I may have a tighter bass. But maybe not if I'm not using an SS amp. Now that I won't be using 4db of bass boost my amp now has more reserve power and I can't crank the 19's up that much in the small room they are in. My ears will bleed or the windows will shatter, whichever comes first.

Mr. Widget

12-13-2006, 04:48 PM

But even if it were possible to get more extended highs from the 802-8G/811B, would they sound the same and disperse the same as from the smaller horn of the EV T350?I've been trying to convince Zilch of this for a few years now.:D

The lighter smaller diaphragm in a proper tweeter not only measures better without the coaxing of network gymnastics, but more importantly they sound better. A good tweeter will reproduce higher frequencies with less glare and hash... a larger compression driver can crank out the highs and that is fine for PA work, but of all the compression drivers I have heard or measured, none of them can compete with a quality tweeter... not even the beryllium models, though they get much closer.

FWIW: I agree with you about the EV T350. It is a fine tweeter. It may use the same diaphragm and thinking as the T35, but it is light years better in sound and measured performance.

Widget

Zilch

12-13-2006, 07:05 PM

I've been trying to convince Zilch of this for a few years now.:DHeh.

By the time I'm done, Mr. Widget will have disconnected ALL of his tweeters.

[We KNOW he wants to.... :p ]

Paul C.

12-13-2006, 07:21 PM

Is this the subject schematic?

Yes, that was the schematic I used for Gary L's xover.

Gary L

12-13-2006, 07:42 PM

Heh.

By the time I'm done, Mr. Widget will have disconnected ALL of his tweeters.

[We KNOW he wants to.... :p ]

LOL, He might just be one of those closet horners:p

The tell-tail sign is caster wheel lines in his carpet.

DaveV

12-13-2006, 10:07 PM

Well Mr. Widget, Zilch and others, I spent the last hour playing bands (tracks) on LP's for a neighbor that has Valencia/Flamencos and maintained that no added tweeter was needed. He was dully impressed and when the stylus fell on Nat King Cole he said, "Oh my God, I'm jealous." He heard the Ahmad Jamal Trio in mono, Stan Getz in mono and stereo , Julie London in mono and stereo, Nat King Cole in stereo, Kirite Kanawa in stereo, parts of Command Provocative Percussion Vol lll in stereo, Gary Carr playing an Amati Bass and conluded as I did that the Model 19's with the T350's are truely amazing. The clarity, detail, air, Altec attacks yet smooth as silk and the bass is there, deep and very well defined. I'm so embarrassed that something as simple as bass and treble boost took me on a needless and confusing path. It's amazing what treble boost can do to bass perception. The 19's sound so amazing that I'm tempted to leave them alone but I know I'll be in there trying the new inductors again. At least this time I have a referrence and now that I know I don't need the bass boost the increased woofer output probably won't be a problem. I never expected the 19's to deliver this kind of bass without some boost and having used the T350's on the Flamencos I was still having to use one detent click or 4 db of bass and treble boost to make that combo sound good to me. There was one thing after another in experimenting with the new to me 19's and apparently today everything was right including the crossover and padding for the T350's to overlap the 802's in their higher operating range with the HF control at 12 o'clock. Then when I got the idea to go flat with the tone controls "the sound" just fell right into place. This combo is by far the best speaker system I've ever had, and I've had many. They are also one of the best I've ever heard regardless of size or price. If new inductors and non inductive resistors open certain things up just a tiny wee bit then they will be beyond amazing. I'm so happy I made that impluse bid on E-Bay and won for $1000 now that I see the last 3 pair of Model 19's have gone for $1600. My cabinets and grilles are fine and even with the moving expenses and having the 802's done at Great Plains I'm not at that price yet. What a bargain compared to many "high end" speakers that I probably shouldn't name. So to make a long story short now that I've made it long, if your 19's don't sound great, then you don't like tamer/smoother horns or there's something really wrong with them or in your associated equipment. I do however still feel that like the Valencias/Flamencos they do need tweeters to really shine and show what they can do. The expansion of breath or air is far less than subtle and the resulting highs, IMHO are far better than the full higher end of the 802-8G/811B with the HF control set at "optimal." I also think that not all cap choices will result in the same sonic outcome if your just replacing the caps. Others have mentioned names of caps so I'll say that I used F-Dyne (Southern Electronics) MPP1's that are metallized polyprops. They worked out great in my Flamencos and with the EV Tweeters so I thought I'd go with a known after I tried another brand that I didn't like the sound of with horns.

Dave

Dylanl

12-13-2006, 10:33 PM

Dave could you tell me what brands and parts you replaced in your xovers. In particular I am interested in the bass inprovement. DO you have any pictures?

DaveV

12-13-2006, 11:10 PM

If you've been following my adventures or maybe misadventures, then maybe you missed a part or misunderstood? I tried replacing the large woofer inductors (2.7 mh) with low resistance steel cores I had one hand that were of a larger value. Using an LCR meter I unraveled turns until I got the 2.7mh. The bass improved for sure but I had another problem with too much upper bass that clouded voice and some instruments so I went back the original Altec inductors and it was better. During this time is when everything fell into place so all of the original inductors,resistors and pots were and are still in the xovers. The caps, speaker connectors and internal wiring are the only new parts other than the replacement foam surrounds around the 811's that I think help in the higher frequencies from the 802/811. If your asking what inductor I tried, it was I believe a Madisound SH steel core very much like the Erst steel or iron core inductors from Parts express. I still plan on trying all new inductors and non inductive resistors in the xovers to see what they do but it would be hard for me to believe that much more improvement could be had. I happened to have some $$$ Cardas speaker terminals on hand that I think are Rhodium plated so I used those to replace the funky spring loaded jobs on the bottom of the cabinets. The internal wire and speaker wire/cable I use was used for a time by Cello Ltd the former high end audio company. It's an all bare copper rope lay design. I think it's a total of 336 strands of wire wound in different twisted bundles then twisted together and jacketed as one conductor and it came in red and black. I always found that wire gave me the best mids and a slightly better bass. I was about to add something to my last post but then I saw yours. I forgot to mention that my 811B's are NOT damped in any way and the vanes are still welded. After hearing what I heard this evening I can't say that I have the urge to even bother. If I do I might try cutting the welds and filling the gaps with black goop but I still don't know why so many people complain about a ringing horn. I'm pretty critical and I don't hear anything I'd blame on the horn itself. BUT, as with my Flamencos, I have the added tweeters and the HF driver isn't running like a system without an added tweeter if that makes any difference or not because I thought the ringing was supposed to be between 1 and 3KHZ. Or maybe it's there but I'm just not sensitive to it?

Tom Brennan

12-14-2006, 04:47 AM

Gary L

12-14-2006, 05:50 AM

JBLRaiser

12-14-2006, 07:27 AM

"If you've been following my adventures or maybe misadventures, then maybe you missed a part or misunderstood? "

Dave----I'm not cracking wise and mean this with all due respect but given that you don't use paragraphs it's difficult to read your posts and easy to misunderstand them. Especially for an old-timer like me with bad eyesight. ;-)

Regards

If you've been following my adventures or maybe misadventures, then maybe you missed a part or misunderstood? I tried replacing the large woofer inductors (2.7 mh) with low resistance steel cores I had one hand that were of a larger value. Using an LCR meter I unraveled turns until I got the 2.7mh. The bass improved for sure but I had another problem with too much upper bass that clouded voice and some instruments so I went back the original Altec inductors and it was better. During this time is when everything fell into place so all of the original inductors,resistors and pots were and are still in the xovers.
The caps, speaker connectors and internal wiring are the only new parts other than the replacement foam surrounds around the 811's that I think help in the higher frequencies from the 802/811.
If your asking what inductor I tried, it was I believe a Madisound SH steel core very much like the Erst steel or iron core inductors from Parts express. I still plan on trying all new inductors and non inductive resistors in the xovers to see what they do but it would be hard for me to believe that much more improvement could be had.
I happened to have some $$$ Cardas speaker terminals on hand that I think are Rhodium plated so I used those to replace the funky spring loaded jobs on the bottom of the cabinets. The internal wire and speaker wire/cable I use was used for a time by Cello Ltd the former high end audio company. It's an all bare copper rope lay design. I think it's a total of 336 strands of wire wound in different twisted bundles then twisted together and jacketed as one conductor and it came in red and black. I always found that wire gave me the best mids and a slightly better bass.
I was about to add something to my last post but then I saw yours. I forgot to mention that my 811B's are NOT damped in any way and the vanes are still welded. After hearing what I heard this evening I can't say that I have the urge to even bother. If I do I might try cutting the welds and filling the gaps with black goop but I still don't know why so many people complain about a ringing horn. I'm pretty critical and I don't hear anything I'd blame on the horn itself. BUT, as with my Flamencos, I have the added tweeters and the HF driver isn't running like a system without an added tweeter if that makes any difference or not because I thought the ringing was supposed to be between 1 and 3KHZ. Or maybe it's there but I'm just not sensitive to it?
http://audioheritage.org/vbulletin/images/statusicon/user_offline.gif http://audioheritage.org/vbulletin/images/buttons/report.gif (http://audioheritage.org/vbulletin/report.php?p=138229)

DaveV

12-14-2006, 10:07 AM

No problem Tom. I know I'm "wordy." Guess I try to make myself clear and then it backfires. LOL
You have the knack for short and to the point posts and be sure that I read them all because I always enjoy reading your opinions.
I was thinking that even though what I have now with the 19's and added tweeters is something else, I have never heard the different VOT configurations (except the Flamencos) and all the various JBL configurations.
There must be enough combos out there to spend 2 lifetimes tweaking for the ultimate sound so there must be plenty of happy Altec/JBL owners as happy with their own configurations as I am with mine.
If we all liked the same sound there would probably only be one speaker because others wouldn't have sold.

Gary L

12-14-2006, 11:12 AM

Sure would like a number of opinions here!

http://img.photobucket.com/albums/v722/Gamalot/19set1.jpg

All the stuff to build two sets of model 19s and all is fresh from GPA.
I plan to build an exact copy with one set of these components but the second set is open for suggestions.

Having no cabinets built yet but soon, I would gladly entertain suggestions from all regarding the second cabinets and if they should be two way or three and what additional components/upgrades I might need.

Here in the NE my carpentry business takes a dive right about now and I can either ice fish or spend my time playing in the shop.
I've spent a boatload of cash getting all this stuff together and rebuilt so I would love to have some input on making the second pair into a Killer set of 19+ speakers.

I have read many good ideas but would really love to hear the very best suggestions as to what to add to make the very best of all worlds with what I have or could get to make the best.

Thank you all for helping here.

Come on Zilch, put your thinking cap on! :D
http://img.photobucket.com/albums/v722/Gamalot/Zilch2.jpg

Gary

Zilch

12-14-2006, 11:50 AM

I'm making my Z19s outta JBL, 4325 cabs comprising the bottoms.

Lemme think what I'd do with those Altec components if I was a cabinetmaker and had 'em.... :hmm:

JBLTEC

12-14-2006, 12:49 PM

Gary, That is an impressive looking bunch of hardware. Is there anything better than the 19? I'd just go for two sets.

Jason

Gary L

12-14-2006, 03:25 PM

Gary, That is an impressive looking bunch of hardware. Is there anything better than the 19? I'd just go for two sets.

Jason

Thanks Jason. To my ears the 19s sound fantastic and I too wonder.

The Z 19s Zilch eluded to certainly have my interests peaqued!

Bowtie427SS calls his idea the 19.5s but the Z 19 has a nice ring to it.

I am not adverse to trying new ideas and with all the talk here and in other threads I just decided why not just make a set to be what everyone thinks is the missing link in the sonic spectrum.
Sadly I am not the tech here and have to ask the experts.

My only ability in this project is building the cabinets and soon to have the time to do it. I need more speakers like I need a hole in my head!

With what I have invested so far a bit more won't break the bank but I sure would love to build a set that will truely blow original 19s out of the water.

What will it take, JBL slots, EV 350s, some other tweek to add what is missing when we all discuss these fine speakers?
When rolling your own cabinets you can do what ever you want because they won't be worth much more then the price of the parts when you are done---except to you.

I refuse to buy a real 19 and put it on the butchers block but it sure would have been cheaper in the long run.

Gary

Mr. Widget

12-14-2006, 03:48 PM

To my ears the 19s sound fantastic and I too wonder.
As with many vintage designs any improvements may fall on deaf ears... I am not suggesting that you are deaf, but you may not want a truly accurate and revealing monitor and may actually prefer a performance to a recreation of a performance... it appears that many on this forum do.

I need more speakers like I need a hole in my head!
I surely understand that one! :D

I refuse to buy a real 19 and put it on the butchers block but it sure would have been cheaper in the long run.I agree completely... I think cutting into any of these vintage pieces is just wrong... if you want to mess around with them, it is easy enough to build a box... if not, find someone to help you... it is fun.

Widget

JBLTEC

12-14-2006, 03:52 PM

Agreed on the box chopping. I had plenty of people telling me how much better my Cornwalls would sound with an 811 mounted in place of the sqwuaker. I don't doubt it as nothing to date even compares to my 511's but I will not cut my cabs just to try it. Gary while you're at it make 3 sets of them 19's and I'll be up to get a pair when you get them done :D .

Gary L

12-14-2006, 04:25 PM

Thanks Mr W and JBLtec.

I probably am deaf to some degree but the funny part is the 19s are the best speaker I have ever heard so it is very hard to hear whats missing if you have never heard it.
I read all these post and all the talk about roll off at 80 MPH or is it Kilos but I don't hear it.
I read all this talk about missing frequencies in the UHF or is it VHF but again, it is hard to understand what you have never heard.

I know most hear have a case of JBL on your brains and I don't fault anyone for their loves. I am a bit over the top with a case of Altecitus so if there is a way to make them better then I am in a position right now to JUST DO IT!

If you never drove a Rolls Royce I suppose a Lincoln town car is a pretty sweet ride.

What upgrades or additions do you guys think should be made to the 19 to make it the "Best that it can be"?
Thats what I am asking here.
I do have faith in Zilch's charts and graphs and I believe in the science to a degree. Can a speaker really be made that fills all the gaps?

I also understand I am working within some limitations given the components I want to use and already have. Surely, with some tech assistance, I should be able to produce a pretty fine speaker in the next month or two.

Weather I will be able to hear the difference is another discussion but it sure would be nice to have all the bases covered with this project.

Gary

Mr. Widget

12-14-2006, 04:47 PM

What upgrades or additions do you guys think should be made to the 19 to make it the "Best that it can be"?First I would seriously consider dropping the crossover point to 800Hz and use the 511 horn... possible even using a larger format Altec driver and the 1.5" entry 511 horn.

A tweeter would provide a real benefit... I would not use a 2402 or 2404... the 2405 is a possibility... the T350 or even one of the Fane or Fostex tweeters.

Depending on your taste in music, if you want to reproduce many CDs recorded after the mid '80s, I'd consider a sub too...

Widget

Storm

12-14-2006, 04:49 PM

Gosh Widget - Are you never satisfied? I would hate to be your wife!

:p

-Storm

Zilch

12-14-2006, 05:19 PM

Mr. Widget

12-14-2006, 05:32 PM

Gosh Widget - Are you never satisfied? I would hate to be your wife!

:p

-StormNothing personal, but I would hate for you to be my wife too. :barf:

Actually after many years of messing around with a wide range of JBL and non JBL drivers and systems... yes Altec and even Klipsch included, I have found a system that I am quite pleased with. It does weigh hundreds of pounds and cost a king's ransom... but for me it works.

Widget

Gary L

12-14-2006, 06:53 PM

If you want to venture beyond merely replicating the existing design, let me advise, unequivocally, that you cannot do this successfully without measuring as you go.

Now, that doesn't mean a big investment in gear, if you can use your computer to do it. You'll need a software package like TrueRTA (1/6 octave version,) a mic preamp, the Behringer measurement microphone ($50) and a mini-boom stand for it, and an XLR mic cable. I haven't tried that package myself, but several others here are going (have gone) that route. Perhaps they or others will be able to advise further.

For starters, build yourself a LF box. I don't know if M19 is the optimum size and tuning for that woofer, but I'll plug it into BB6P for a preliminary look. As you know, I don't do Altec, typically. Perhaps others will have some suggestions on that part.

Once that is complete, the real fun begins. You'll be able to see how various driver/horn/network combinations work and sound in comparison to your M19s, and you'll be able to dial THOSE spot on to your listening space and frequency response preference. :thmbsup:

O.K., what's the specific Altec woofer model number you want me to run in BB6P then?

I was hoping you wouldn't send me in this direction! I would much rather disect a crossover, which I know nothing about, then to install yet another program or two into this dammed computer that causes nothing but STRESS.
Model 19s typically use the 416-8B woofer and I have a set of them and a set of 416-8As, both are the 16" wide framed models and as far as I can tell identicle.
HF drivers can be 802-8Gs with tangential phase plugs or 808-8A with standard metal phase plugs and all have new GPA 34647 8 ohm aluminum diaphragms and all are freshly remagged and or reconed. The horns are 811Bs, the black pair has dynamat dampening while the green pair are stock. I also have standard, stock 19 XOs for both sets or the new ones made by PaulC from the Jeff Markwalt schematic you posted above and pictured in post #1.

My hope is to add to what I have and end up with a very nice, mostly altec speaker for set number two. I am sure I could add a tweeter here and an additional horn there and come up with a four or five way KABUKI I could sell from a white van.

Thank you for your help

Gary

grumpy

12-14-2006, 07:00 PM

...possible even using a larger format Altec driver and the 1.5" entry 511 horn.

Factory-damped 1.4" entry 511E ? ... Wouldn't mind a pair of those myself.
Unfortunately, they don't seem to pop up too often.

GaryL, do you already have the factory M19 plans that are available online?
http://home.earthlink.net/~jmarkwart/

-grumpy

Gary L

12-14-2006, 07:22 PM

Thank you Grumpy! I do have J Markwarts site but have to get to a friends computer with HS to do the download and printing. This click and wait crap with slow dial up is more frustrating then you might imagine.

I do have friends with 19s close by and can do allot of the measurements from the real cabinets as well. Mine will be sufficiently braced, unlike factory cabinets and this too might add some sonic differences.

Gary

JBLRaiser

12-14-2006, 10:01 PM

Zilch

12-14-2006, 10:18 PM

L220 as sub?

Ooops!

O.K., 416-8A isn't in the BB6P database, but 8B and 8C are.

For comparison, I need the M19 LF cabinet gross internal volume and port dimensions, please. :yes:

If somebody has or can link me to 416-8A T/S parameters, that'd help, too....

Gary L

12-15-2006, 06:19 AM

Thanks Zilch. I am liable to get flamed for this but IMO the 416-8A and the B are one in the same as far as the T/S go. Both use the exact same coil and cone and I have never seen the T/S for the As.
The LF cabinet port is 11" by 2 1/2".
Some confusion exists with the internal volume because the lower box is open to the upper box which adds additional volume inside. I don't even have a clue how to measure exact interior volume. Here
http://img.photobucket.com/albums/v722/Gamalot/Altec19restobegins10-18-06007.jpg

Gary

Dylanl

12-15-2006, 06:29 AM

Too bad you can't pour water in it.

Gary L

12-15-2006, 07:01 AM

Actually Dylan its too bad it is not mine or here so I could just do the measuring and give some exact numbers.
I could come up with some close approxamations but would prefer someone in the rebuild process to take some real measurements.

Cabinets are 30" wide so interior is 28.5.
They are 20" deep so interior is 18.5
I don't have the seperate box heights right here and also have to consider the black seperator between both as well as the horn mounting face being inset some.

I think on the site that Grumpy provided above by Jeff Markwart the numbers are there but it takes so freaking long to get anywhere from here with dial up.
I am also at a bit of a loss in determining how much interior space to subtract for bracing and component intrusion.

Gary

Zilch

12-15-2006, 10:43 AM

Zilch

12-15-2006, 10:46 AM

Too bad you can't pour water in it.I've done that with packing peanuts a couple of times, actually. :D

DaveV

12-15-2006, 11:01 AM

Gary,
As a newcomer to Altec talk I don't have enough hands on knowledge as many here that have been trying different Altec combo's for years but as an "outsider" looking in I have seen comments and things I'd question if I were wanting to re-invent the 19 so to speak with the same components or different components. And I have questions about my own adventures with the 19's. Here's some things to think about.
1. is there really an issue with "double tuning" in the 19 due to the 811 enclosure being a box on a box or is that pure speculation?
2. did Altec find that the spacing between the 811 and 416 was the optimum for one reason or another or does it really matter that much?
3. did Altec come up with the best cabinet size for the woofer without taking the driver displacement into consideration? Not that that's much space but if your looking for more perfect then that's a question.
4. cabinet bracing cuts down on bass reducing panel vibrations and resonances but if you do that to some vintage speakers you might find that they don't sound as good because all resonances don't sound bad.
Kind of like the time I put my Flamencos on "audiophile" brass cones and it sounded like I EQ'ed 3db off of the highest bass output.
The model 19 cabinet is pretty solid but maybe some bracing would help and I don't think any inherent "nice" resonance would be killed in this case.
5. so far I like the foam around the 811's on my 19's but that could boil down to personal taste even though the 19's came with the foam. If the 811 baffle were not sunken so that the cabinet edges protruded the whole diffraction issue would almost be a mute point in my opinion.
6. Would a test show that by using a different cabinet lining other than fiberglass and more like carpet padding show a difference in the woofer response/impedance curve?
7. is there a good reason to keep the bug screens on the 802's and how many seasoned horn users of any kind have removed them and thought the sound was better? I did and I do. Same for my EV HF drivers.
8. there seems to be a "thing" about ringing metal horns no matter what forum you look at. This and that horn rings like a bell. Well DUH. They ring like a bell when they aren't secured to the cabinet like in the 19's but is there still an audible ring or not? Is it only SPL sensitive/related? If there's so much controversy over the ring and what to use to cure it and you still want to use a metal 811's then why not make the woofer cabinet larger, don't have a "slot" to the upper 811 enclosure and fill the upper enclosure with sand around the 811. Now you have a 200-240 pound Model 19 but the sand can be removed if the 811 enclosure has a removable top. Because that enclosure is no longer being used as part of the woofer volume it does not have to be totally airtight. Just sand tight.
9. in a perfect world shouldn't the woofer and 811 horn have foam or rubberized cork gaskets to maintain a pefect seal to the cabinet?
10. having had Flamencos prior to 19's I knew that I needed an added tweeter and I knew that I would probably need them on the 19's even though others said no because of the better HF response of the 802-8G's. Well I did need them. But adding a tweeter opens up another issue of proper crossover so the tweeters "take over" from the 802/811 and not compete with it. I have yet to solve that problem but the addition of the tweeters is still an improvement to me even though I know I have too much overlap. If your maintaining the original 19 xover but adding a tweeter, is it as straight forward as adding an inductor across the 802 and using a series tweeter cap and parallel inductor on the tweeter? Then is the tweeter really out of electrical phase? With a 6db/octave xover I know I like the tweeter magnets in line with the 802's for time alignment so "proper" tweeter addition can get complicated and require electrical and acoustic measurements.
11. to who's sonic taste do you tailor an improved Model 19 too? The people that like the full bore of the 806/802 or the people that like the tamed 802 via the EQ in the 19 xover? Some commented that flat isn't good but that's what "audiophiles" strive for. But then again 50% of so-called audiophiles wouldn't use "colored" horns. Tweeter or no tweeter? So does one "improve" without altering a stock 19's sound or not? Clarity and bass extension excluded.
12. Better quality parts in an older xover can normally improve the clarity of the sound and improve the bass but sometimes there are snags with things like resistance that some vintage woofers may need to sound just so. I don't think this is the case with the 416-8B or C though. I also think that there's going to be a different sonic outcome with different caps. IMHO a paper in oil is going to be softer and maybe darker sounding than with metallized polyprops. In my experience this would become more obvious in the HF driver and very obvious in a tweeter or UHF driver. To eliminate the debate over "core saturation" air core inductors can be used but if they aren't the better expensive variety with heavier gauge wire the resistance is fighting you and how much better will they be over the original Altec inductors? More electrical tests and acoutical tests to see if anything is happening in the way of altered response.
13. the bi-amp advocates say to bi-amp the 19. In theory that might be correct but in practice that makes for a whole different sound unless your going the way of a fancy equalizer that can adjust much narrower frequency ranges than the common Radio Shack equalizer can. The bass may be tighter with bi-amp and some may hear a cleaner high range but do you really want to go there? There's the expense of the electronic xover network, the equalizer and the extra amp. Then will you be happy with the results?
14. Anyone ever try a Valencia/Flamenco N-800F xover with the 19's to see what that sounds like? But that just might be a hybrid 846 with better bass and better HF response and a lesser Model 19?
15. There's the debate over horns and crossover points. Mantaray, 511 or 811. Xover at 500HZ, 800HX or 1200HZ. Well do you want an improved Model 19 or something closer to a "Voice of the theater" than the 19 is?
You seem to be searching for opinions and advice so I thought if I threw these things out it might help you determine which way you want to go and help determine what you need to know.

Dave

Dylanl

12-15-2006, 12:02 PM

Here are the plans

Gary L

12-15-2006, 12:03 PM

I've seen the plans here before, so the actual dimensions are available. Link us, someone, please.

The insulation damping adds enough virtual volume to compensate for the bracing, and I can estimate the volume displaced by the horn; the gross internal volumes of the two boxes will get me close enough.

Baffle thickness is 3/4", right? So that's the depth of the rectangular port.

Others have done this, no doubt, but it's always good to work up an independent determination.

The initial look said the "B" stands for "BIG" box. :p

Thanks Zilch. Here goes!
The baffle is 3/4" as is all other materials.

THESE ARE ALL INTERIOR MEASUREMENTS!

Big box- 28 1/2" W X 22 1/2" H X 17 1/2" D

Small box- 28 1/2" W X 9 1/2" H X 15 1/2" D

Spacer- 24 1/2" W X 2" H X 15 1/2" D

This should be as close as I can get to the total interior volume of all three together.

Please don't trust my math skills here but it looks like 16177.99 CU IN.
or 9.362262 CU FT.

Gary

Dylanl

12-15-2006, 12:03 PM

Gary what about a design like this? Dual woofers

Dylanl

12-15-2006, 12:04 PM

Back.

Gary L

12-15-2006, 12:26 PM

Thanks DaveV, Lots of great points there and some excellent thoughts on the subject.

As you dillegently point out, many of these questions either have not been answered or the answers are in the ears of the listener.

My goal, if it is at all possible, is to make one set of completely stock 19s that for all intents and purposes should end up sounding pretty close to what real 19s sound like. Pretty close because I will use either MDF or Particle board, both standard products from Home Depot. This will certainly not match what original cabinets were made from so there lies a difference from the giddy-up.

My other set is what I want to play around with. Add a tweeter or second horn. Change some XO values or do what ever those who have a grasp of these discussions think will fill the gaps where the original 19s fall short.

When all is said and done, I will have both pairs set up for some real A/B testing to see which sounds better to me. Even then it will not be the optimum test because the only room I have that can fit 4 19 sized speakers sucks for listening. That not to forget that my ears should never be relied upon for any degree of accuracy where others are concerned.
I might get a pair that sounds great to me and terrible to some others.

I will probably build the second set in such a way that I can change baffles if i need to try various tweeter or horn configurations. They will likely not be the double box with seperator as this will restrict me in other variations.
Winters here are long and cold so I am sure I will have a few months to play around.

Gary

Gary L

12-15-2006, 12:40 PM

Thanks for the plans Dylan, I saved them too!

The dual woofer design is another consideration and in keeping with altec I think I would use the 414-8C because it has a better mid range curve.

I am not real fond of the 511B horn idea mentioned by Mr Widget although it might be the better horn of the two. Simple reason is because I have a bunch of 811Bs and no 511Bs and they do require quite a bit more room in the cabinets.
I am thinking the 416 woofer with a 12" 414 could be a nice match to fill in where the 416 is lacking.

Just thoughts right now though because I have a nice set of those here.

Good thing I have PaulC to help me in the XO department because every different driver change will require completely different XOs.

Gary

Mr. Widget

12-15-2006, 12:54 PM

The dual woofer design is another consideration and in keeping with altec I think I would use the 414-8C because it has a better mid range curve.I have no personal experience with this driver, but it makes sense... one reason I suggested lowering the XO point was that 1200Hz is way too high for any 15" cone in my opinion...

As for the 511... you specifically asked for, "What upgrades or additions do you guys think should be made to the 19 to make it the "Best that it can be"?

If you use the word "best" around me, I will toss out regard for cost and practical considerations like what is on the shelf... the 511 is significantly better sounding... Altec most likely made the compromise due to marketing concerns... beyond the fine folks who read these posts, how many people want a speaker that is even larger than the Model 19!

Widget

Mr. Widget

12-15-2006, 01:00 PM

My current preference for "Best" speakers... using these components would be to use your 15" 416-8B on bottom, a 414-8C as mid bass, 511 horn and driver, and the tweeter of your choice... it would be a fantastic system... possibly weak on ultra low frequencies, but this is not necessarily a problem especially if Model 19s perform well in your room.

Widget

Zilch

12-15-2006, 01:07 PM

No duct behind that port opening, right?

It's 9 cuft tuned to 41.65 Hz according to BB6P.

Usable bass (-10 dB) to 30.85 Hz.

1.35 dB "bump" at 60 Hz.

BB6P didn't like the database T/S parameters and recalculated Vas, bottom. It made virtually no difference in the result; the bump is 1.39 dB with the original published T/S.

Gary L

12-15-2006, 01:07 PM

Yes Widget, we are a Mottly Crew when it comes to speakers and sizes. Most of my friends think I need brain surgery!

If I had a set of 511Bs there would be no question about giving them a spin. Maybe someone here needs 811s and has 511s to trade. I have never had both side by side but I do know they are a bit heftier.

The other thought about going to the larger throat and different drivers is totally out of the question. There is a bottom in this wallet and I keep getting closer by the day.

Keep in mind also that no matter what I do or however great they sound or look when done, they won't be worth much more then the cost of the materials---- If that. If anyone here thinks you can make money doing stuff like this then please think again.

Gary

Gary L

12-15-2006, 01:19 PM

No tube or duct behind the port at all Zilch. What you see is all there ever was in these cabinets.

WIsh I did know how to interprate what the charts and graphs are showing.

Would a tube or duct help with LF in these according to the data?

Gary

Mr. Widget

12-15-2006, 01:24 PM

Would a tube or duct help with LF in these according to the data?It would lower the tuning frequency... this would lessen the bass bump and extend the bottom a bit. Personally, I'd look into it, however, if you like the 19's bottom end this will lessen the impact and boom.

Widget

Zilch

12-15-2006, 01:36 PM

BB6P suggests an improved high fidelity alignment in 7 cuft (orchid,) 0.5 cuft larger than the stock bottom box alone.

That's like incorporating the spacer volume into the bottom by making the bottom box a couple of inches taller and closed at the top, moving the woofer up the same amount. Put the ports near the bottom.

Another option if you want to retain the stock cabinet proportions would be to close the spacer at the top and put in the new ducted ports instead of the existing rectangular one.

Tuning is two 4" diameter ports, 5" long for 32.15 Hz. Three 3" ports @ 4.25" long will work, too, it says.

Cone excursion limit is lower, and bass more extended. Useable bass drops to 28.48 Hz.

That's what I'd build for the "X" experimental version. Just looking at the plots, I'm almost certain it would sound better to me:

moldyoldy

12-15-2006, 02:13 PM

FWIW, there's been some speculation that the reduced area of the cabs' "connector sleeve" with a larger area above may cause cavity resonance. I have no idea how to determine if a signifigant effect is produced other than to build an equivalent volume single compartment cab and measure and compare.

Gary L

12-15-2006, 02:33 PM

It sounds just like these which are the first 19 clones I built.
Two 4" ports 5" deep with woofer raised 2" higher and no seperation.

http://img.photobucket.com/albums/v722/Gamalot/Cab12.jpg

http://img.photobucket.com/albums/v722/Gamalot/A-4.jpg

Gary

Zilch

12-15-2006, 03:33 PM

And how do THOSE sound, Gary?

What's the internal volume?

[Looks like you're done already.... :p ]

moldyoldy

12-15-2006, 04:31 PM

It sounds just like these which are the first 19 clones I built.
Two 4" ports 5" deep with woofer raised 2" higher and no seperation. Gary

Problem with that layout is mounting both units to a common baffle messes up the vertical alignment, so unless biamped with appropriate phase delay will be a real mess.

Whatever you end up with will need to;

1. Mount components so voice coils are vertically aligned, or
2. Select crossover point and slope to best match phase at XO for the chosen alignment (method used on 19s), or
3. Use active XO with variable delay to correct phase alignment.

Just my 2 cents, but given the 416/802/811 component set, I believe Altec intended to, and successfully achieved, utilizing the components full potential with the Model 19. I just can't picture them saying "let's intentionally make this model fall short of its' potential so users can improve it themselves". Therefore, with the exception of biamping, which I highly recommend, I think you're chasing your tail trying to make a similar, yet superior system with the same components.

That said, I'd suggest either 19 clones and sell a pair if you don't need them, or a totally different type of system, like the 820 corner horn for instance (a much older design that doesn't need to be re-engineered either).;)

Zilch

12-15-2006, 04:55 PM

Gary's using the M19 crossover with those, I believe, Moldy.

There's little doubt that M19 can be successfully "augmented" with UHF.

Widget has suggested adding a midbass driver and lowering the LF frequency.

[Plenty of stuff to explore with the M19 driver set.... :bouncy: ]

moldyoldy

12-15-2006, 05:05 PM

Gary's using the M19 crossover with those, I believe, Moldy.

That's my point. 19s have offset component mounting, so if using a 19 XO, but altering the vertical position by mounting both without the offset, you've got problems.

Gary L

12-15-2006, 06:30 PM

Very interesting here. I had no idea verticle allignment even played a roll.

My current clones come in a 7.4944 CU. FT. total interior Volume and have 2- 4" ports with tubes that extend 5" into the cabs.

I think they sound great but this is where I get lost in the soup. I am perfectly satisfied with them but fully understand I am attempting to duplicate a sound from memory.
They do not sound like my old 19s and I can't discern where the difference is with these old & imperfect ears. I just know they are not 19s and can't say why or where from.

My current bass is sharper and punchier yet not as smooth as the old real 19s. Horns don't seem to sound any different at all. I also think my clones would not handle as much power as the old 19s when cranked past where I ever do. Actually they don't need to because they seem to sound better with less. It is deffinately a different kind of bass comming from my clones then what came from my real 19s. Wish I had the test equipment to tell me where the difference truely is but it is not in any way offensive or muddy or a problem, just different. This might have everything to do with cabinet materials, stiffness, insullation and the fact that my memmory is based on what my old music sounded like to much younger ears.
Pretty much nothing has remained the same so I might be dead in the water before I start.

Now for a question to those of you who have the equipment and programs to make solid assessments of your own speakers.
Do you search for what the programs and test devices say is right or what your ears say sounds best to you?

I can build my set in any one of many configurations. I can use the exact components I have and seperate both boxes or leave them in one box. I can add tweeters or additional horns, increase or decrease overall size and just like the rest of us, I could be totally happy with the results of totally disappointed. I have said this a hundred times on the forums and think it still holds true today. The very most expensive and highly rated speaker in this world might not impress these ears.

For anyone here who is more of a novice at this then I am, I don't think there is any one set of rules to follow or for that matter any one particular sound you might achieve. As Zilch pretty much eluded to above and many others have added to, there has to be some testing with the ears you are attempting to please because there is no way of making the exact right speaker.

Gary

Dylanl

12-15-2006, 07:28 PM

Problem with that layout is mounting both units to a common baffle messes up the vertical alignment, so unless biamped with appropriate phase delay will be a real mess.

Whatever you end up with will need to;

1. Mount components so voice coils are vertically aligned, or
2. Select crossover point and slope to best match phase at XO for the chosen alignment (method used on 19s), or
3. Use active XO with variable delay to correct phase alignment.

Just my 2 cents, but given the 416/802/811 component set, I believe Altec intended to, and successfully achieved, utilizing the components full potential with the Model 19. I just can't picture them saying "let's intentionally make this model fall short of its' potential so users can improve it themselves". Therefore, with the exception of biamping, which I highly recommend, I think you're chasing your tail trying to make a similar, yet superior system with the same components.

That said, I'd suggest either 19 clones and sell a pair if you don't need them, or a totally different type of system, like the 820 corner horn for instance (a much older design that doesn't need to be re-engineered either).;)

I posted another thread looking for plans for the 820A I would love to build it. Do you know where I can find wokable plans?

Zilch

12-16-2006, 01:14 PM

Now for a question to those of you who have the equipment and programs to make solid assessments of your own speakers.
Do you search for what the programs and test devices say is right or what your ears say sounds best to you?Once you get set up to measure, you will quickly appreciate the correlation between how stuff measures and how it sounds. You'll be able to recognize why it sounds the way it does, and alter that, as desired. You acquire control.

It goes to the fundamentals: getting the desired balance between drivers, then the desired frequency response from each of them, and the blend. Even a simple RTA can take you well beyond these basics and into more sophisticated design disciplines.

Does that tell you how it's going to sound? Yes, in general terms, perhaps 60 or 70% of the total result. Different drivers sound different. Different horns sound different. Different cabinets sound different. Different layouts sound different. Different rooms sound different. Read Dickason's "Loudspeaker Design Cookbook." He explores how to measure all of that stuff.

In the end, the choices become subjective, but measurement carries you most of the way efficiently and, most importantly, objectifies the choices. Contrary to some opinions here, the ear may be the ultimate arbiter, but it is also a notoriously unreliable instrument - what sounds good, even to yourself, is not absolute. You have to rely on the measurements.

Watching the RTA, it took more time for me to get the dime out of my pocket to do it than to balance Oznob's L110s here.

"Holy CRAP," he said. "I never thought they could sound like THAT!"

[Or words to the effect.... :p ]

Gary L

12-16-2006, 04:28 PM

Thanks Zilch, great explaination and I can respect the measurements a bit more now.
I have heard speakers that were highly tuned to various test equipment and sound anylizing meters. Frankly, I found them rather boreing.
Thats not to say they did not sound good but they did not sound like what I think is good.
There is allot more to this then simply my ears and I notice very often what sounds good to me does not sound good to most others which is exactly why I asked.

Gary

Zilch

12-16-2006, 04:37 PM

I have heard speakers that were highly tuned to various test equipment and sound anylizing meters. Frankly, I found them rather boreing.The key to this is doing it yourself. YOU control the outcome. Measurements merely facilitate the process of ascertaining what sounds good to you, and how to achieve it.... :thmbsup:

Mr. Widget

12-16-2006, 05:25 PM

Once you get set up to measure, you will quickly appreciate the correlation between how stuff measures and how it sounds. You'll be able to recognize why it sounds the way it does, and alter that, as desired.Yes and no in my opinion...

I certainly believe in taking measurements... I take lots of them while looking for specific things that I heard subjectively. However taking a look at a FR plot for the most part has very little info as far as whether or not a speaker will sound good. There can be a massive in-room bass hump and yet the speaker still sounds dry and tight... the bass may look relatively flat and yet it sounds bloated and boomy. The plot may show a response out to 20KHz yet it sounds hard and bright with no air, or conversely it may look soft on top yet sound really good.

Personal preference is another can of worms entirely... however since acquiring CLIO and a calibrated mic and being able to take really accurate measurements I have learned how important really listening actually is... I believe if you talked with Greg Timbers or any of the successful loudspeaker designers they would agree just how important careful listening is in the design and evaluation process. No one will put away their mics, but the mic and graph is still only a hint of what we hear. Ultimately every customer has a stereo pair of highly resolving audio test devices.:D

Widget

Gary L

12-16-2006, 07:54 PM

I am very fortunate that I can get some help and direction from knowledgable individuals here at LH.
Basically you guys can wind me up and point me in a direction where good sound might be found. I don't ever plan to get much more involved in building speakers then to do it as a winter hobby and I do not have the technical or computer skills to set out on yet another adventure buying and learning how to use the testing equipment you speak of.
I can certainly appreciate the value of such equipment and programs but there is a point where many of use have to make choices with our time and how best to spend what extra cash we have. My choice is to just play around and build a few sets of speakers that I have absolutely no need for but I do want to get them as close to right as I can.

I hope that does not change the will to assist me and I do wish I was closer to those of you who have the equipment and have spent the time learning how to translate the results.
One of the worst or best parts of the forum is that I have made a number of good friends from being here yet I have never actually met one of them in person. Here where I am there just is not many Vintage collectors who share my love of good music and sound and I would venture a guess that this is the case for many of us. It would be a pretty lonely sport without the forums.

Gary

ngccglp

12-16-2006, 09:05 PM

Hi Gary,

Vertical alignment is absolutely important, but you don't need to invest in those equipment to get it right.

If you are using the M19 XO, then what you need is probably for someone to give you the exact offset dimensions of the 811 and 416 in the M19. You'll probably be 95% there. And if you must, fine tune further with CDs you are very familiar with.

I have successfully adopted the M19 XO to my 288/1005. I don't need no 2405 anymore. I used Hovland for the bypass caps. The depth and details is just amazing once you level the response. The optimal setting for the mid is about 7 for the 288/1005 vs 4 for the 802/511. I must say the M19 XO is a very important piece of network for all who doesn't wish to dabble in active setup.

Zilch

12-16-2006, 10:21 PM

Transcend technophobia for free here:

http://www.trueaudio.com/rta_abt1.htm

http://www.trueaudio.com/

ngccglp

12-17-2006, 12:21 AM

Here's a pic of my DIY M19 equalization network. The transformer is to match the impedance of the 288-16G to the N501-8A (not in picture) and the equalization network.

DaveV

12-17-2006, 03:51 PM

Being an old "tube jockey" I can keep my old tube equipment going by troubleshooting and parts replacements, change caps in xovers and try this and that different part in an existing circuit to see what sonic differences there may be but I don't have the knowledge needed to analyze circuits.
The question I have concerns the way that the Model 19 xover is layed out and I can't figure out if it was done this way as a cost/assembly time savings issue or if this particular configuration is needed to achieve the desired results of an EQ xover like this one.
My specific question relates to the way the 802 is connected to the plus (+) woofer or now common plus connection for both 416 & 802 but after the .3MH inductor.
Altec said there was interaction between the MF & HF controls and I'm wondering if some electrical/sonic improvement could be had by changing the layout.
What would happen if the all the 802 xover parts or elements were all put in parallel with the plus and minus input points of the xover and were no longer part of the woofer plus line?
The 2.77 would then in theory need to be a 3MH?
L1 and R1 would remain but their connections would be in parallel with the xover inputs and the plus input of L2 would go direct to the xover plus input.
The way I see it is that the only changes would be that the .3MH is no longer in series with the 2.77MH and that the two drivers could now have dedicated plus and minus lines from the amp inputs on the xover.
Could this not lead to better driver control and sonic clarity with no interaction plus open up the possibility for bi-wire should someone wanted to try that?
Sounds too simple to me so I suspect there's a reason why it was done the way it was but does anyone have the technical reason why it's done this way?
If I haven't made myself clear by my description, then look at the schematic for the N1201-8A xover, break the connection to L2 after the point where the R1 pot wiper line is connected, then draw a new connection line from the input side of L2, where you just broke the connection, over to the black dot on the left indicating red terminal.

http://home.earthlink.net/~jmarkwart...s/n1201-8a.pdf (http://home.earthlink.net/~jmarkwart/sitebuildercontent/sitebuilderfiles/n1201-8a.pdf)

Zilch

12-17-2006, 04:10 PM

It's a good question: how to split M19 crossover for biamping and retain the HF compensation. I'll explore that a bit with sims, perhaps this evening.

I am presently clueless as to why the designer might have done that.... :dont-know

DaveV

12-17-2006, 06:39 PM

Zilch,

Maybe you misunderstood me because you say bi-amp in your reply.

My question referred to a possible bi-wire capability with the change in component topology, not bi-amping.

Bi-wire as in running two conductors from each amp output terminal. One pair being for the woofer xover circuit and one pair being for the HF driver xover circuit so that the physical parallel connection between both ranges is at the output of the amp and not on the xover board.

I know there's controvesy over the validity of doing this because it borders on "high end voodoo" but I'm not looking for comments on bi-wire. My point was that the possibility would be there if someone wanted to try a bi-wire configuration to make up their own mind about it.

The reason I was asking about a topology change was to ask if there might be a sonic/electrical improvement to be had by getting the .3mh out of it's current position in series with the 2.77MH and then having both woofer and HF driver on their own two lines back to the amp input on the xover board. Maybe like better driver control. But would taking the .3MH out of it's current position in series with the 2.77MH upset the whole HF EQ network for some reason?

Yes, you could bi-amp too and keep the HF EQ network but then that doesn't answer my specific question question because the 2.77MH and the 21uf cap (C3) would be gone with areal bi-amp setup would they not?

Could be that either way the answer would be the same but I wanted to make sure you understood what I meant.

Dave

Zilch

12-17-2006, 07:03 PM

Yup, gonna look at just splitting them apart first.

Figuring out how to biamp with an external crossover will be tougher.

We may have to call in the big guns for that.... :p

DaveV

12-17-2006, 10:58 PM

Update to my December 13th post where I had "upgraded" the 2.7MH inductors, had too much bass and muddyness to voice then finally realized I just wasn't used to having speakers that didn't need bass or treble boost and had forgotten my preamp was at +4db boost for both as it had been for 15 years with 2 other pairs of speakers I previously owned to make them sound good to me.

Well I put the "better" 2.7 MH inductors back into the circuits and there seemed to be a lack of bass with the flat preamp settings.
I called it quits and didn't listen to anything for a day.

When I listened tonight I heard a whole different speaker. With the original 2.7 MH inductors and just new caps there was a hole or thin sound between the woofer and mids that made the mids a bit harsh at times, the human voice a bit to thin, the mids a bit too real or "alive" but the bass was really there.

What I heard tonight was the filling in of the "hole" so the mids don't sound harsh any more, human voice is more full but not chesty and the "alive" mids are there depending on the program material but now I hear for instance, a more natural sounding voice with realistic very clear and sharp sounding instruments behind the voice. A contrast showing that the two do exist on the recording.

The bass is there when it's supposed to be and it's way tighter and more in balance with the mids and highs.
I have never heard my Mac 225 tube amp make lows like this with any speaker. You would swear there's a 100/channel SS amp on the woofers in bi-amp. The woofer control is amazing and really almost too much. No more rolling floppy bass.

Because I finally got my added tweeters crossed over better to just overlap the 802 highs and not add or compete and with the xover HF controls at 12 o'clock, the overall balance is there and these are the flattest sounding speakers I've ever had yet they have that open horn sound.
The added tweeters blend so well they sound like they belong or are part of what's coming from the 802/811's.
I'd have to say that this flat smooth sound won't appeal to everyone but after listening to orchestra, voice, jazz and semi techno or electronic music, I have to say that the speakers simply sound more like live music would sound.

I thought all this might be helpful to people interested in "upgrading" the model 19 xover because I am now convinced that you can make these speakers sound pretty much any way you want them to assuming of course that the mid or HF horn is what you like in the first place.

I haven't changed the design other than add tweeters direct to the amps with a simple 6db/octave xover, changed the xover caps and just the 2.7MH inductors so these are still Model 19's but with removable tweeters.

I still think that voicing with caps is critical if your after a just so sound and obviously the large inductor change was a shocker to me. Some may prefer the less controlled bass with the original inductors? It does sound more impressive but not as well defined and controlled.

Even with all the confusion and frustration I'm glad I did this piece meal rather than just jump into all new xovers and accept the sound I got as "upgraded" and that's it.

Any further improvement will be frosting on the cake.
Hope this helps someone in their adventures with the 19's.

Dave

Zilch

12-18-2006, 01:50 AM

What 2.77 mH inductors?

Bama5000lps

12-18-2006, 05:32 AM

This is my first post so I hope I am not repeating an earlier post.

I have a pair of 19’s that I have been updating. Two years ago I changed the caps and resistors and I was very pleased with the results. Now I would like to update the inductors but I am confused about the inductor values on the schematic. I have reviewed the schematic versus my crossover and I know that my C1 is 21uF as the schematic states.

The schematic looks official but I am having trouble recreating the design based upon the values of the inductors on the schematic. I know the values of the capacitors so I should be able to back calculate the inductor values.

The literature for the 19’s states that the crossover point is 1200Hz. Using several “on line” crossover calculators I am trying to reverse engineer the crossover knowing that C1 = 21uF, LF = 8Ohms and HF = 8Ohms. Using a Second Order Butterworth calculation I am able to obtain the C1 = 21uF with a 670Hz crossover point; the Inductor TOTAL (L1+L2) value is 2.7 MHz. The 19’s have two inductors in series with a combined value, L1+L2 of 3.0 MHz so if the first inductor is actually 0.3Mh that would make the second inductor 2.4 MHz. Is the L2 value actually 2.4 and not 2.7. This would help to explain why people think the 800 Hz is the correct crossover point; 670Hz is much closer to 800Hz then to 1200Hz.

If the 19’s are crossed over at 1200Hz the C1 value should be 17uF and the L1+L2 should be 1.06Mh.

I hope that this is not too confusing! As you can tell I don’t design crossovers for a living.

Hillman

12-18-2006, 05:39 AM

Hey Gary, This is what they should look like when you get done. Thanks to Dave Wojo's, Mojo, When I rebuilt the X-overs, I stayed with the same values as the originals thus the stacking of capacitors. Really guys, I would not have these if Gary had not talked me into buying them. They were a mess and belonged to a band at one time. Thanks for all the help guys.

stephane RAME

12-18-2006, 05:43 AM

Hello, 2 photographs of my filters has 600hz/6db and 12db, with potentimetre or autotransformer.
-GPA 515-8G For Low-Frequency Loudspeakers >600Hz/12dB
-GPA 399-8A For High-Frequency Drivers <600Hz/6dB
-GPA MR 60x40 for Horn

DaveV

12-18-2006, 06:51 AM

What 2.77 mH inductors?

L2 2.7MH sorry. I had an extra 7 in there. It's been corrected in the original post.

Zilch

12-18-2006, 10:52 AM

This would help to explain why people think the 800 Hz is the correct crossover point; 670Hz is much closer to 800Hz then to 1200Hz.Nobody's friggin' MEASURED it? It's the ACOUSTIC RESPONSE of the crossover in the system that defines it. What would lead you to believe it's electrically Butterworth, even?

If the 19’s are crossed over at 1200Hz the C1 value should be 17uF and the L1+L2 should be 1.06Mh.MEASURE!

Here's my sim (again):

http://audioheritage.org/vbulletin/showthread.php?t=12305&page=4

Here's the sim with the controls set to "Optimum." Move the green curve up ~10 dB (What is difference in sensitivity between the two drivers, HF on the horn?) to approximate the acoustic response. Where does it cross with the LF? (2, 4, 6, 8, 10,...)

http://audioheritage.org/vbulletin/showpost.php?p=128863&postcount=49

Bama5000lps

12-18-2006, 01:21 PM

Zilch - Then the schematic is correct?

Sorry for my first post.

Thanks

Zilch

12-18-2006, 01:45 PM

Zilch - Then the schematic is correct?
I don't know. It'd be good if someone verified the component values shown with factory originals, if that has not already been done.

I have difficulty getting reliable results measuring laminate-core inductors with various instruments here, and I don't have an impedance bridge to verify.

Seems several have built from the schematic successfully, and the sims conform with original specs and CBS testing of the product.

Appreciate that few manufacturers use "textbook" approaches to crossover design. Instead, filters are engineered for particular combinations of drivers in specific systems, and the best DIY starting point may be the original design.

EDIT: More sims temporarily delayed. I'm loading and measuring the Z19s right now.... :bouncy:

Mr. Widget

12-18-2006, 02:13 PM

This is what they should look like when you get done. Congratulations!

Those look really nice... a lot of the Altec heads prefer the oak cabinets... I personally think the walnut is really nice and yours look particularly sweet. I am glad to see these brought back to life.

Widget

Gary L

12-18-2006, 04:08 PM

When Hillman first got them he fibbed to his wife and said they were for for me.

OK Tommy, tell her I am comming for them! LOL

Really they do look sweet and I already know they sound great.

Sorry if I kind of fell out of the discussion but the tech stuff is a bit more then I can understand.

One of these days Zilch, I am going to send you a pair of real 19 XOs so you can really play around with them. I can't imagine how any of you techies can figure out anything without the real thing in your shop.

Gary

spwal

12-25-2006, 10:28 PM

this is a very informative thread guys. keep up the good work!

Sean

analog addict

04-11-2007, 09:48 AM

...been following very closely because I recently fell into a pair of M19's and even in stock form, they have to be the best speakers I've ever heard. However, a friend from AK has convinced me that the bass response is not all it should be, and I am already knee deep in planned changes and upgrades. Here are the pix of the stock beasts...

As you can see, I wound up with one 416-8A and one 416-8B. I've made a deal to purchase a single 416-8B, and have followed Dave Wojo's advice in ordering Solen caps for a X-over upgrade...However, I'd like to hear more about people's experience with other mods, including the inductor upgrade, and possibly biamping. I also came across a pair of Jensen RP103 horn tweeters recently, and was toying with the idea of adding these to the mix..What would be the design of a simple 6db crossover for the Jensens?

Could anyone give me a few suggestions on how to proceed as far as getting the absolute best from these Bad Boys?

Thanks,

Zilch

04-11-2007, 11:16 AM

There's new info on Model 19 in the Valencia upgrade thread, beginning here:

http://audioheritage.org/vbulletin/showthread.php?t=14690&page=33

I would NOT add tweeters to M19, rather, swap in the BMS drivers which play to 20 kHz, instead, keeping the M19 crossover.

A small additional filter will knock down the peak at 19 kHz, if you find that's worth doing.

One or another of you AK Altec guys is gonna have to invest in some measurement equipment. I've made some recommendations to Macaltec.

I would not mess with biamping at this point, for the reasons I outlined in the M19 sim thread here....

DaveV

04-11-2007, 11:40 AM

Sounds like me. Overall I'm very happy with my Model 19's BUT there's that urge to "make them even better."

For me, without doubt, they do lack the HF flatness and extension required to hold my interest in a speaker.

But with lots of experimentation with added tweeters, they have made a big difference and everytime I listen I'm pleased so I must be at least close to having it right. Meaning close to the right xover point without too much overlap with the 802G's that aren't rolled off with anything more than the HF control on the xover. I have them at around 1 o'clock.

Having one 416-A or Z that may be 16 ohms isn't helping your bass.

Overall I'm very pleased with the bass on my 19's with the understanding that it's particular "tuning" is a compromise like most are but it floats my boat compared to other speakers I've had and most important to me is that I have bass with NO bass boost or EQ.

Personally I think the 19 xover isn't what it could be for best overall performance but what xover was back then? It can be improved to suit your own "beliefs" and sonic taste but if your a true tweaker, I'd build breadboard xovers where you can change parts and configuration easily to hear the resulting differences. Of course it all depends on what you end up doing. Duplicating the orignal xover with "better" parts, changing the HF driver, adding tweeters or going bi-amp.

The fad for expensive everything doesn't always sound the best and cap choice is another matter altogether. Lets just say that I'm not a Solen fan and I think people should try at least several types for themselves so they can hear the differences rather than just accept someone elses cap preference.

Sometimes I think the original xovers with new caps of my choice are just fine but that urge to tweak is ever present so I'll be looking for ways to make the 19's more enjoyable to me. It all may end up with the original oxvers with new caps but at least I will have satisfied my urge to improve and still have very listenable and enjoyable speakers.

Right now your best bet would be to read the ENTIRE thread about the Valencias with added EV tweeters. That would be a very good start in your inquiry.

http://audioheritage.org/vbulletin/showthread.php?t=14690

Dave

Zilch

04-11-2007, 12:02 PM

But with lots of experimentation with added tweeters, they have made a big difference and everytime I listen I'm pleased so I must be at least close to having it right. Meaning close to the right xover point without too much overlap with the 802G's that aren't rolled off with anything more than the HF control on the xover. I have them at around 1 o'clock.I'd have difficulty figuring out where to do that as well:

http://audioheritage.org/vbulletin/showpost.php?p=160762&postcount=492

The HF control isn't just HF, of course. It establishes the contour of the compensation filter, though I'd work it the other way, i.e., get the MF set to balance with LF, then adjust HF to get the right amount of compensation for maximal flatness. The controls interact, so that might require several iterations to get it right.

The problem with adding a tweeter to M19 is the same as we documented for Valencia -- getting one to integrate with that horn is a bugger. That's why I favor the single-driver approach; all of those problems go away....

Earl K

04-11-2007, 12:09 PM

One or another of you AK Altec guys is gonna have to invest in some measurement equipment. I've made some recommendations to Macaltec.

I can agree with that. It would be nice to see the diehard Altec crowd do some of their own heavy lifting .

There's new info on Model 19 in the Valencia upgrade thread, beginning here:

http://audioheritage.org/vbulletin/showthread.php?t=14690&page=33

I would NOT add tweeters to M19, rather, swap in the BMS drivers which play to 20 kHz, instead, keeping the M19 crossover.

A small additional filter will knock down the peak at 19 kHz, if you find that's worth doing.

- Since I like the sound of the original driver ( or at least the 902 ) I would recommend that someone attempt a rework the M19 crossover . ( but not me / since I don't have one any interest in these brutes / plus, I believe in "motivated self-interest" driving these sort of projects )

- A couple of suggestions :

(i) Try bypassing that inline 3 ohm resistor. This should restore ( according to my calcs. ), 2 to 2.5 db of output to the overall horn circuit ( it'll be dependant on the actual AC impedance of the horn/driver combo ) . Eliminating this resistor will raise the rollover point of the 6uF cap from around 5 K to around 12 K ( & since I don't really know the AC impedance of the driver/horn combo everything is just an estimate ) .

(ii) - To restore things to the original balance of the HF to Midrange ( with the 3 ohm resistor eliminated ) one is going to have to increase the value of that 6 uF bypass cap. I'd do this empircally while looking at the display of an RTA . This will also lower the impedance curve for the HF as the HF bypass kicks in so run some impedance curves of the overall network .
- One might want to add a fairly wide 4200 hz notch ( via a series LCR across the driver or a parallel LCR inline with the driver ) to smooth out that bump ( see Zilches plots of the 802-8G on the 811 horn ) . The choice of a series or a parallel type LCR will be driven by the overall AC impedance of the circuit .
------------------------- ATERNATIVELY

- after removal of the 3 ohm resistor one could ;
(i) Just live with listening to the HF having a steeper compensation slope ( a la the 4430 / at the expense of a bit lower sensitivety )
(ii) add a small inline coil to the 6 uF cap to create a UHF resonance around 14K / as in the 4430 approach . The Q will be a bit wider so the gain in db may not be very much . Still the addition makes some circuit sense by adding some resistance back into the circuit in the UHF range ( for stability ) .
(iii) The same advice on adding a notch filter holds true here also .

I would not mess with biamping at this point, for the reasons I outlined in the M19 sim thread here....

- Since I biamp everything / I would pursue a work around to the biamping hurdle .

Anyways , these are just some ideas for someone who wants to tweek their M19 crossover / you'll obviously need some test gear / ie; at least an RTA .

:)

Gary L

04-11-2007, 12:13 PM

"STOCK", Yours are certainly not! I seriously doubt the switch from your 16" 416-8A to a 16" 416-8B will produce any significant result but I do agree it is nice to have the correct drivers.

19s were designed for home use and had a base that was no more then 3" tall which put the horn at just about ear level when seated. This also allows the LF to couple with the floor and as many times as I tried all the different set ups, raise them, lower them, tilt them, I never found any better sound then from stock bases and away from the rear wall 6-8 inches. Your current set up has the HF going right over your head and the LF loosing out on the relationship with the floor in front of them.

I would loose the training wheels, drop the base down to where it is supposed to be, switch the woofer if that will make you feel good and try listening for a while as they were designed to be used.

Certainly, many have said there is some lack in the HF and the fix that Zilch mentions above will most likely add what may be missing. For around $250 if you can better the HF with the BMS drivers and still have the stock drivers this is a no brainer for me.

You might also do some further investigation to be sure you have 802-8G drivers with Tangerine phase plugs and either 23744 or 34647 diaphragms.
Check your phase plugs while there to be sure they are tightly glued in place.

Keep in mind that speakers like the Model 19 attained their "Cult Like" following because they just sound good just the way they were built. There is nothing wrong with doing some experimenting along the way but I will strongly advise against making any irreversible changes to them. They command a decent value as they are in stock and original fit and finish but you will quickly deminish what value they do have by making changes that can't be reversed.

Gary

Zilch

04-11-2007, 12:24 PM

It would be nice to see the diehard Altec crowd do some of their own heavy lifting.

I would recommend that someone attempt a rework the M19 crossover . ( but not me / since I don't have one [or] any interest in these brutes / plus, I believe in "motivated self-interest" driving these sort of projects )

I hope I've provided some insight, but I'm about done with it too, as Altec's not my "thing." There seem to be a group of people with enough interest and expertise to pursue the various approaches suggested, and develop their own in course. The missing piece has always been the measurements; it's as if Altec'ers never really wanted to know.... :blink:

19s were designed for home use....Well, I'm not so sure about that. The one spec sheet we've seen is for them as studio monitors:

http://www.altecpro.com/pdfs/vintage/SpeakerAndMics/speakers/19%20Hi%20Fi%20Speaker%20Manual.pdf

There's also this, tho:

http://www.altecpro.com/pdfs/vintage/SpeakerAndMics/speakers/19%20Hi%20Fi%20Speaker.pdf

Earl K

04-11-2007, 12:48 PM

The missing piece has always been the measurements; it's as if Altec'ers never really wanted to know....

I'd say the statement is overstating a "developed history", by a fairly large amount / because ;

- I believe that no other forum but this one ( worldwide ) has the capacity to allow the necessary number of attachments needed to encourage group interaction on these performance questions . This forum has been quite JBL-centric since its' inception.
- Todds' forum relies on external image hosting which ( at this point in time ) discourages group interaction on indepth design questions .
- AA has the same limitation and is further kneecapped by the fact that threads expire in a linear fashion & can't be revitalized by renewed interest .
- diyAudio is overall quite good, but still it only allows one attachement per post ( and that is not seen in full size within the overall thread ) . That hampers the flow of discussion .
- AK , I'm not registered at , so I don't know it's limitations .

:)

Chas

04-11-2007, 01:00 PM

[quote=Zilch;162049]I hope I've provided some insight, but I'm about done with it too, as Altec's not my "thing."

Great! Now, what about those TOTL JBL two ways......:)

Zilch

04-11-2007, 01:11 PM

Great! Now, what about those TOTL JBL two ways......:)Some horns here, some in transit, and some "pending." :p

DaveV

04-11-2007, 01:19 PM

I was typing my last post while Zilch had already posted his so mine wasn't meant to fly in the face of anything Zilch had suggested.
I just wanted to make that clear.

Without yet having and hearing the BMS drivers I can't comment on them other than they sure do look like the best and least complicated HF extension fix by viewing the response curve plots.

I'm not unhappy with "character" of the 802G's but they just don't do what I like higher up so my jury rig tweeter addition works for me and would be livable for me even if I went no further, but of course I will.

I think for the cost, the BMS drivers should be tried by anyone not happy with the Altec driver HF extension.

I have to agree with Zilch that his response curves plus the info in the two model 19 threads is enough to go from here otherwise his new job will be customizing Altecs for everybody.

The response curves were a big help to me for sure. They sure confrmed what I was, or wasn't hearing with the 806A and 802G's. Thanks Zilch.

The Valencia " shootout" in Arizona has yet to happen and that should be very helpful as well.

Dave

Gary L

04-11-2007, 04:21 PM

I kind of feel like there is a leak in the boat that has floated this thread and particularly the "Look at my new babies" thread for well over 600 posts! Hope my sharp pen didn't cause it but I do understand the desire to move on.

Where else in this world can we find the technical expertise involved here to acheive the results nestled within these threads?

I had very high hopes that Zilch would fall deeply in love with some of the Altec offerings and go about his usual plan of attack and rework the heart and soul of them for the optimum listening pleasure. I really think he has provided invaluable info and insight and might not be as impressed as many Altec lovers with the basic beginnings or end results.
I applaude his outstanding efforts and those of the many here who have made contributions to the cause.

I am pretty sure there are many Valencias that will sound a great deal better now and some other Altec speakers that will benefit from this effort.

Here is what I have learned.

Every speaker can be worked and re worked to sound a bit better then first designs.

No company has a lock on what sounds best.

Great sound can be found in drivers that cost considerably less then the ones we search for day and night.

Test equipment can tell the real story in terms of Black and White but may leave some of the grey areas out.

Weather you like Tubes, SS, JBL, Altec or any of the other sizes and/or styles is not at all an exact science to your ears.

I still can't hear my wires! I still like my Altecs! I still enjoy comming to forums that delve deep into this passion we all have and we will probably still argue over what is the best.:duel:

I propose a :cheers: to the efforts put forth here by Zilch and the many who have contributed to this awesome thread.

I hope to hear some results from the shootout when Storm gets done with his previous engagements and can make this happen. I am now certain that his idea of what sounds best is very different from mine.

Thank you Zilch!

Gary

JBLTEC

04-11-2007, 04:29 PM

[quote=Zilch;162022] snip......................One or another of you AK Altec guys is gonna have to invest in some measurement equipment. I've made some recommendations to Macaltec. quote]

Thanks for that Zilch. It may be a while but I'll get around to it. It'll be fun to see what is happening and how changes take effect. I have gleened much from our discussions and am now just letting it soak in and awaiting the day to make my own discoveries and attempts at improvement.

spwal

04-11-2007, 05:05 PM

This is a great thread. I am infinitely grateful to Paul C whose outstanding work and congeniality got my Altec 19s singing like a bird.

best,

spwal

analog addict

04-12-2007, 08:54 AM

"STOCK", Yours are certainly not!
I would loose the training wheels, drop the base down to where it is supposed to be...

Thanks, for all the advice Gentlemen. As far as losing the wheels, since they are in the middle of the living room, and don't have a permanent home yet, I am loathe to lose the mobility that the casters provide. Besides, it hopefully motivates my wife to make a decision on a new home. My only stipulations - 3 car garage and a mancav..I mean basement. My current favorite and one of two in the running is illustrated in the included pix/links. 16' to 20' ceilings, and in the first picture 50' long, and in the second, about 67' long. I can only imagine what the M19's would sound like.

I am hoping that JBLtec/Macaltec/Jason will get a set of the BMS 4550 drivers, because I think that would be the easiest way to accomplish my goals, along with a X-over upgrade. Do most people advocate also changing/upgrading the inductors, or just leave them alone?

By the way, both 802-8G drivers are untouched, and have the stamp across the back end intact as in the 3rd picture. Currently I'm not going to mess with them, unless I have a chance to try Jason's new acquisition(s)...First things first, recap the X-overs and change out the 416-8A for an 8B.... Also, after having hooked up a SONY STR 7800 SD last night, it's amazing what a few extra quality watts can do to bring out the bass in these beasts...Thanks again...

PS. DOn't get me wrong, I have nothing against JBL products. I have a pair of 4301b's and am considering a pair of 4430's I know can be had sometime in the future...I need to recover from this purchase first....:banghead:

Gary L

04-12-2007, 10:12 AM

Thats a date code showing they were made in the 48th week of 1977. You will probably find 033952 stenciled on the rear cover but when you remove the diaphragm to check the tangerines you should find 23744 stamped on the underside of the coil. Some could also have 34647s in them but many here claim the 23744s are the best, I can't hear any difference.

I do have to wonder what was the purpose of raising the base height that much. Kind of makes the speakers look awkward. I would think you could leave the casters while your in transition but the base should be shortened so the speakers are about 3" off the floor. The idea is to have the horn at ear level when you are sitting in front of them on a standard couch or easy chair and to allow the bass to interact with the floor.

House looks monsterous so you might need all they can give.

Gary

Zilch

09-19-2007, 12:10 PM

The reference link to the 1978 CBS Labs review of the Model 19 (post #9) is now dead.

Did anyone save the .pdf, and would you upload it as an attachment here, please?

:banghead: Zilch STOOPID! :banghead:

TnTn

09-19-2007, 12:39 PM

I didn't look at the link, but here's the pdf.

garyl

09-19-2007, 01:03 PM

I think I have it printed out Zilch!

It says "A consumers Guide, New equipment reports" and Model 19, A Standout performer from Altec, from February 1978.

I tried to scan it so I could add it here but my scanner is not doing a very good job.

PM your Address if you would like me to send you a copy of the article.

Gary

TN beat me to it while typing but thats the one I have.

Zilch

09-19-2007, 01:20 PM

Thanks, gang.

That's REALLY fast!! :thmbsup:

DaveV

02-11-2008, 10:56 AM

The inductors in my Model 19 xovers that according to the schematic should be 2.7mh actually measure 2.36 and 2.40 mh.
I switched in low resistance 2.80 inductors and I'm not sure if I like the results more than having the originals in.
Now I'm wondering if the lower value was intentional or if maybe there was a slight change in the later 19's that used the 416C woofer and that's where the 2.7 value was used.
Thought I'd check to see if anyone else has measured the inductors in their 19 xovers or if they might have a spare xover they could do that on.

Gary L

02-11-2008, 11:32 AM

Hi Dave. I have plenty of spare 19 XOs but not a clue how to measure any of the values you seek.

I've seen in many threads where guys have recapped with various types and values and most of what I have gathered from discussions is that the so called designer caps that get quite costly don't necessarily add to the sonic value of the sound.

My knowledge is of little value in these discussions but if my DMM is able and you can direct I will certainly give some assistance.

Gary

Zilch

02-11-2008, 11:49 AM

I'll be doing some measurements with them this week, and will get the inductors for you.... :yes:

DaveV

02-11-2008, 01:35 PM

Gary L

02-11-2008, 03:06 PM

Gary,

I am aware of the "voicing" that can be done with different brands and type of caps so I use the ones that sound the best to me and they aren't the expensive ones for sure.

I have added tweeters on the 19's and a cap change there is much more obvious than elsewhere.

I was tinkering with trying to get more woofer control/speed and more clarity between the woofer and mids so I switched out the so called 2.7mh original inductors with new 2.80's that should be close enough and I wasn't entirely happy with the results. The bass seemed tighter but vocals and other lower midrange body seemed to suffer some and that's when I meausred the original inductors and found they both weren't 2.7mh.
So that made me wonder if they were all more like 2.40 than 2.7.

This might be a case of voicing the speakers to my equipment and/or room but I would like to know what more of those so called 2.7's really measure out as.

Zilch,
If you can measure one or two that would be a help to me.

Thanks
Dave

You need to search the "look at my new babies thread" and listen to alot of the info we learned from all the testing we all chipped in on.
Only a couple ever came up with adding a tweeter that made a positive difference in their own ears. Most tended to think just adding the BMS 4550 or 4552ND was the best of all worlds with the 19s and Valencias and it was as simple as swapping drivers.

I don't think audio Nirvana was acchieved but it did get pretty close the what the masses seemed to want. I also think both Zilch and Mrwidget can produce some mighty fine charts and graphs with their own experimentations but again they won't come cheap nor will they be music to the ears of us all.

I hope that just once in my life I can have an opportunity to listen to the holy grail of sonic purity in a loud speaker while played through the holy grails of electronics and from the best of the best source material.

I'm not at all disapointed in my current system and in the grand scheme of things I am running just some mediocre stuff and doing fine with the music I enjoy. We all have many pre conceived notions but by virtue of the lack of funds and lack of knowledge I will stick to what I have and enjoy.

Gary

DaveV

02-11-2008, 05:08 PM

Gary,

I followed that "New Baby" thread all the way from start to finish and I have played with my tweeter addition since.

I have absolutely no problem with the added tweeters. They are sitting at the back edge of the cabinets and sound like they are part of the Model 19's because to my ears they blend very well and it sounds like their output is coming from the center of the 811's.

I was tempted to get the BMS drivers but I've never liked any 2 way sysyem I've ever heard because something was always lacking so I figured that would be the case here too.
Plus I did buy the 19's being 90% sure I wouldn't like them without tweeters so it's no big surprise.

Without them the 19's are not listenable/enjoyable to me so they made a huge difference and now with better bass and smoother mids than my Flamencos had, the 19's sound like a reasonably flat full range speaker in my room with my equipment.

I had the same tweeters (EV T-350s) on the Flamencos too but with a larger cap and that makes sense to me because the 806's weren't quite as extended as the 802G's with the comp network in the xover.

The T-350's don't go out beyond 14KHZ but they sure open everything up
because the lower range (6db/octave xover) reinforces the dwindling 802G response I guess. HUGE DIFFERENCE!
And yes, Bill at GPA remagged and put new diaprams in the 802's.

I just can't listen to program material that I know contains brushes on cymbals or bells, etc yet you can't hear or bearly hear them not to mention the improved clarity of instruments and voice.

I've concluded that a lot of people like the rolled off Altec sound but I've also concluded that I'm not one of them yet I do like the Altec drivers with an added tweeter. Finding the right xover point and padding is the tricky part.

But now because the upper end is opened up and crystal clear I was trying to do the same toward the bottom frequency range but to a much lesser degree than was needed to please me on the top end.

In one of the Model 19 or Valencia threads someone mentioned a Sony recording studio in CA that added EV T-350's to Model 19's and I wish I could find out more about that. They must have heard what I'm hearing and liked it too.

Dave

spwal

02-11-2008, 06:48 PM

I thought zilch once told me that i didnt need to augment the 19 with a tweeter...

i wish i still had them, i would totally play around with an external crossover if i had them. oh well, they have moved on and are missed. fantastic pair of speakers!

Gary L

02-11-2008, 08:28 PM

Thanks Dave. I have no problem at all with what you are attempting to achieve. My attitude always fall to it is your ears so go for it.

I do kind of liken it to back when I was younger and everyone who had a VW wanted to put a Porsche engine in it.

I'll probably always wonder why folks who detest the sound of model 19s and consider them "unlistenable" would even bother owning a set.

I don't doubt for one second a great combination can be found to bring the 19s into your desired listenable state but it just seems to me you are running all the way around the block to get accross the street.

Are there no decent 3 way speakers in a similar price range that already have what it is you are seeking? I would think a nice pair of JBL L 300s would fit the bill here and be much cheaper in the long run.

There is also always the possibility we just like messing with our gear and trying to make what we have more then they are as I suspect is the case here.

Again, I have no problems with however you choose to get what it is you want but I also hapeen to feel the 19s when functioning properly have many great attributes but they are not the do all end all of speakers and likely never will be no matter what we do to them.

Gary

Mr. Widget

02-12-2008, 10:04 AM

I thought zilch once told me that i didnt need to augment the 19 with a tweeter...Don't believe everything you hear. :D

However do believe everything you do HEAR. :bouncy:

Widget

Mr. Widget

02-12-2008, 10:13 AM

The T-350's don't go out beyond 14KHZ but they sure open everything up
because the lower range (6db/octave xover) reinforces the dwindling 802G response I guess. HUGE DIFFERENCE!I'd suggest that if your T350s don't go out to beyond 18KHz there is something wrong with them.

Here is a plot of some T35s with their much smaller magnet than the T350s... the more powerful magnet raises the mass break point and therefore the high frequency extension. If you are curious to see the effect, look on that same thread a few posts later Zilch posts some plots of a T35B with an even smaller magnet than the T35... the highs are quite rolled off.

http://www.audioheritage.org/vbulletin/showpost.php?p=199171&postcount=34

Widget

DaveV

02-12-2008, 11:28 AM

Mr Widget,

I guess I should have been more specific.
I used 14KHZ as the what I'd call a solid usable frequency limit without EQ of some kind and these are the older T-350's from around 1965 or before.

They do go out to 20KHZ but they start dropping pretty quick at 14KHZ.
At the time I also had a pair of Altec 3000's and a pair of EV T-35's checked out and they were similar in the upper limit but the T-350 is more efficient.

It seems that I like the "character" of the sound produced by the T-350 more than the Altec 802G in the upper frequencies and obviously there's some HF extension now too so incorporating them is still a work in progress as to how far down to get them to work.

In the original system they came from they were crossed over at 3500 12db/octave to EV T-25A's with the original fiberglass 8HD horns and that was a nice smooth sound. Could be the pheonlic diaphrams in the T-25's?

I guess "my thing" is the character of the sound.

When I moved to a smaller house I couldn't take all of my big speakers so I ended up trashing the EV Regency cabinets so now I can't compare the Model 19's to them but I still have the drivers.
Who knows. Maybe I'll end up using with the EV's again now that I have a wall they can be mounted into with lots of space behind for the 15W woofers to work into.

The quest for the perfect transducer, that doesn't exist. LOL

Dave

Zilch

02-12-2008, 12:47 PM

I thought zilch once told me that i didnt need to augment the 19 with a tweeter....They don't NEED tweeters if they're working up to original spec, and especially if you've upgraded the HF driver. That doesn't mean you can't add one if you want to spend the rest of your life diddlin', twiddlin', and 'sperimentin' with them. :D

i wish i still had them, i would totally play around with an external crossover if i had them.All is not lost. Build a bass bin, stick a horn and driver on top, and tweak AWAY!

http://audioheritage.org/vbulletin/showthread.php?t=9901

Note: M19 box is too big for its driver.... :yes:

AltecLansingFan

02-12-2008, 01:30 PM

Many people say, Altec Lansing model 19 is one of the best sounding models Altec ever made. I'm an Altec fan since 1969, and I listened a lot of different models. I think model 19 is the best model. But also may people say the 811 horn is the best horn for a 1" driver. So my last project (this winter) is to build the most optimal speaker with Altec components as 416-8B speaker, 811 horn (including some gypsum work), 808-8B driver and for some higher frequencies, and some more air in the sound a ESS Heil Air Motion Transformer on top. The sound is what you hear by your ears, and that is very depending on in what kind of room you are listening. I think the room can makes your sound fantastic or bad. I think Altec is a the ideal speaker to play with, I mean a normal Altec speaker enclosure with standard Altec crossover sound very forward. If you want a wide sound wall, like you hear a life band playing, that's what I prefer, you can change/upgrade the crossover and you can accomplish fantastic results.
I used the crossover schematics from Jeff Markwart's model 19, upgraded this crossover with North Creek 10 AWG Music Coils. These coils are really wonderful, and they sound much much better than the Mundorf coils.
Solen caps, witch I (later)upgraded with Hovland bypass caps. Later I want
to try (test) the Vishay o.o1uF bypass caps instead of the Hovland's. But now at this time I'm very happy with the results, the sound of this speakers is remarkable, exceptional detailed and very open. I created a perfect wide sound wall, it is like you hear life music. Now I must finish the enclosures and the job (I think my last speaker job) is finished.
http://i31.tinypic.com/2yzdgty.jpg

http://i30.tinypic.com/eu39fp.jpghttp://i32.tinypic.com/21277uw.jpg

Chas

02-12-2008, 01:54 PM

They do go out to 20KHZ but they start dropping pretty quick at 14KHZ.
At the time I also had a pair of Altec 3000's and a pair of EV T-35's checked out and they were similar in the upper limit but the T-350 is more efficient.

FWIW: Years ago I had my T-35's re-'phragmed by the then, current EV owner, Mark IV. When I spoke to the tech who did the work, he told me the 35's and 350's used the identical diaphragms, i.e. phenolic. He also said the only technical difference was +3 db effeciency increase due to the larger magnet size of the T-350.

AltecLansingFan

02-12-2008, 02:26 PM

They don't NEED tweeters if they're working up to original spec, and especially if you've upgraded the HF driver. That doesn't mean you can't add one if you want to spend the rest of your life diddlin', twiddlin', and 'sperimentin' with them. :D

All is not lost. Build a bass bin, stick a horn and driver on top, and tweak AWAY!

http://audioheritage.org/vbulletin/showthread.php?t=9901

Note: M19 box is too big for its driver.... :yes:

I tried many enclosures for the 416-8B the last 35 years, the only thing I can say is the 416-8B need a lot of space, you need at least a minimum enclosure of 235 liters. But that's is for my ears, and conform what my doctor told me: my ears are in very good shape. (as you can see on the picture) :D

DaveV

02-12-2008, 04:01 PM

AltecLansingFan

02-12-2008, 05:57 PM

Altec Lansing Fan,

Thanks for sharing your project. I have a few for you questions.

Did you duplicate the Model 19 xover as per the schematic and NOT change any values? You just used better parts correct?

Then that means you used 2.7mh inductors in series with the woofers correct?

What is the xover point (frequency) and attenuation rate (db/octave) for the Heil Tweeters?

I agree with the wall of sound

Thanks
Dave

Yes Dave, I only duplicate the schematic, and only used better parts.
I also used 2.7mh inductors, exactly like the schematics.

The crossover point for the Heil AMT Tweeters is 9000 Hz. (cap 4.7 uF) I use them just to support the typical horn sound. In the beginning I though, I need an Lpod to reduce the volume of the Heil AMT tweeters, but after testing the volume of the ESS Heil Airmotion Transformer was exactly the right volume. I don't like the Twigly-Digly-Ding-Ding sound, what you can get from a tweeter. :moon:

Very important: The other parts of the system.
I tried many different amplifiers and preamps, Quad, Sansui, McIntosh, Denon you can name it, till now the best system for me is what I have now.
My system is very very simple and not expansive:
Very important is the preamp; I used for many many years always McIntosch. But after I learned how things work between analog and digital
I combine analog (old) and digital (new) with enormously succes.
So first I bought a Densen D-200 preamplifier (www.Densen.dk (http://www.Densen.dk)) with lifetime warranty! And that's my preamp number 1 till now.
I can tell you, in combine with a push pull 300B Tube amplifier (with TL FullMusic Premium Mesh Plate Globe Shape tubes) that's a wonderful combination.
CD player:Quiet new on the market the chinees brand Jungson Magic Boat SACD tube cd player.
Cables/interlinks: preamp-->poweramp Monster Retro Gold
preamp-->CD player Monser M1000i
poweramp-->speakers Monster Studio Pro 1000
Just for the low frequencies (below 35 Hz) I use a Klipsch RW 12 subwoofer, only to support a little.
That's all, no preamp with dual chassis, no DAC, nothing.
My best friend (he is a friend for over 50 years now) he owns a very expensive audio set: McIntosh C100 preamp, 2xMcIntosh C1000, JBL K2 and 1x JBL Tik subwoofer, AudioNote DAC, Technics CD player, he comes oftentimes to me to listen to the music, and he is astonished how these old Altec boys sounds. It's a little amazing for him because years ago (in the seventies he also owns Altec speakers, but in that times the todays affordable upgrade parts were not there or the knowledge was not there.)
So try something, and you will get a super sound from your old Altecs.
The big difference between JBL and Altec is I think, the JBL is super in HIFI quality sound, Altec Lansing is super in producing a real LIFE sound.
Thanks

spwal

02-12-2008, 07:21 PM

Don't believe everything you hear. :D

However do believe everything you do HEAR. :bouncy:

Widget

oh my man, you have made me a believer and you know it. all the secrets have been revealed to me...

DaveV

02-12-2008, 10:50 PM

Altec Lansing Fan,

While building your xovers, did you try removing the first small inductor before the 2.7 and the HF pot then just run the HF line direct to the + input?

Or did you find that you needed to adjust that pot because of the added tweeters?

I never saw an answer from anyone as to exactly why that inductor and pot is even needed. It's not like there's a abundance of highs to be cut from the 802G/811 or some of us wouldn't be adding tweeters.

Mr. Widget

02-12-2008, 11:18 PM

FWIW: Years ago I had my T-35's re-'phragmed by the then, current EV owner, Mark IV. When I spoke to the tech who did the work, he told me the 35's and 350's used the identical diaphragms, i.e. phenolic. He also said the only technical difference was +3 db effeciency increase due to the larger magnet size of the T-350.It's widely known that EV used the same diaphragm in both drivers. I doubt your tech was actually correct in his assessment however. I would be quite surprised if the T350 had the exact same FR curve as it's smaller brother(cousin?) I am speculating though as I never measured one and it is true at some point pouring on the magnetic flux will not extend the high end of the driver's range. However based on EV's original specs and knowing what we do about driver design, I am inclined to believe the T350 has a bit more extended top end in comparison with the T35.

Widget

Zilch

02-12-2008, 11:35 PM

I never saw an answer from anyone as to exactly why that inductor and pot is even needed. It's not like there's a abundance of highs to be cut from the 802G/811 or some of us wouldn't be adding tweeters.Its function is described in the M19 crossover sims I posted. It establishes the attenuation at the very high end, i.e., the starting point for the contour rolloff of the mids. What I never found out is why it was derved from the LF path.

http://audioheritage.org/vbulletin/showthread.php?p=128826&highlight=Gary#post128826

Markwart simply eliminated it in his designs, which may be fine for 806A in Duplexes, since they can't play up there, practically, anyway. 802s and 902s CAN, so we have put it back in a different location in the current 9844 upgrade here:

http://audioheritage.org/vbulletin/showthread.php?p=197971#post197971

DavidF

02-14-2008, 08:22 PM

" ...
Note: M19 box is too big for its driver.... :yes:"

Por favor, please expand. Thought that the M19 box ('bout 9.4 ft3 I think) was still a little shy on volume for lowest bass extension and flat(ter)bass. Don't know that, just my thinking based upon unverified TS specs. A smaller box was used in the 846 but tuned way differently. May try to build some boxes some day and the difference between 6-7.0 and 9.4 ft3 is significant in my environment.

David F

Zilch

02-14-2008, 09:49 PM

Earlier in this thread:

http://audioheritage.org/vbulletin/showthread.php?p=138472#post138472

Read on to the next page.

416B/C parameters are in the box modeling databases. It's A/Z that are not published anywhere, so for those, I use some measured ones from the Altec Forum.

Doing that, 846 et al. is too small for its woofer, and M19 is too large for its, subject to verification, of course. The tunings are also not optimum. Recalc before building anything, tho. I just click buttons here.... :yes:

m6bigdog

03-04-2008, 12:14 PM

Its function is described in the M19 crossover sims I posted. It establishes the attenuation at the very high end, i.e., the starting point for the contour rolloff of the mids. What I never found out is why it was derved from the LF path....

Any thoughts on adjusting the acoustic phase alignment between the drivers?
I assume the Altec engineers had a definitive reason for the component placement.

Gents,
A newby here; to the Lansing Heritage Forum.

I have been lurking for some time with much interest for the not so simple task of passive crossover design, simulation, electrical and acoustic testing. I love the accomplishes of Zilch the “Curve Junkie” and others on this Forum.
IMHO, obsession is everything, therefore, if a little is good and a lot is better then way too much is just about right!!!

Excuse my verboseness, while I ramble a bit. :blah:
If you want to skip my introductory gibberish skip to;
Inductor - World's Worst Passive Component?

I am experienced in analog circuit design and simulation with an intense passion and interest for music reproduction. More recently I have added high-definition video sound reproduction (Blu-ray, PCM, DTS-HDMA, Dolby HD True Audio) to the task for my sound system.

My technical background is in Electronics Engineering with 40 years of R&D with experimental systems and data acquisition experience. However, I hobby with passion in many technologies and crafts.
I am by no means an expert on crossover design and I have great respect and appreciation for those that have an in-depth understanding of the numerous element of this technology.
I have avoided it until now. One of the speaker system characteristics I would like to explore more is the issue of coherent phase relationship (phase coherent, phase aligned, transient accurate) between the driver & crossover and how that effects speaker performance. Without a doubt, the acoustic output/performance of the driver is the most difficult to accurately measure, heaven knows I’ve tried.

30 years ago, I fabricated a pair of walnut veneered, custom A7X-VOTT (511B, 802-8G & 416-8B in an 828 cabinets with the LF horn flipped, reflex port at the bottom & the 511B horn inside the top part of the cabinet) for my listening pleasure.

The drivers are bi-amp’ed with Crown D-75 & D-150A-II. The active crossover is a custom Salley-Key 500Hz-18dB/octave HP with a derived LP (6dB/octave). Yep, I’m aware of the derived crossover foibles (+4dB LP peak at xover point and LP 6dB/octave slope issues). IMHO, given, all the optimization variables surrounding sound reproduction the issues of a derived LP filter isn’t that big of a negative.
As with most owners of large speakers (200-lbs each), they were placed on the floor in the room corners. Several years ago, I hung them in the ceiling corners (reflex port & woofer on top) and the performance of the bass was enhanced substantially.

Oh yeah, my interest in passive crossovers:
So with all the HD video with true hi-fi sound tracks, I have taken up the challenge of building some better surround sound speakers.
I used a Yamaha DSP-1 and upgraded to the DSP-3000 for 2-channel surround sound effect for many years and have since moved on to a pre-amp processor that can better handle the music and AV 7-channel (I don’t need a sub-woofer) program material with surround sound effects. I was using some small Klipch surround sound speakers (6.5" base driver) and I have come to appreciate more bass in the AV surround sound low frequency effects (LFE). I am also hoping to enhance the imaging between the VOTT and the side surround sound speakers. If I’m successful I will make a pair of center channel speakers driven in mono-mode.

For the SS side speakers, I’m attempting to clone some Altec Model 14 with a M931-1 horns, GPA 902-8A and GPA Model 3127. I have some 1.5-1.75 cu-ft base-reflex enclosures that I will rework to install the components. I’m assuming these drivers better match the VOTT sound field and will enhance surround sound imaging.

I have spent some time evaluating and running sims of the various crossover topologies to include the Model 19. All I can say is, it is easy to make an electrically ideal crossover (Bessel, Linkwitz-Riley, etc. alignment) however the drivers are not perfectly stable (impedance, etc.) nor are they an acoustically ideal transducers (as I read in one article – ‘electrically summed is not the same as acoustically summed’) therefore I anticipate the ideal text-book crossover will fail the primary task every time. That is, getting the most out of the drivers installed in the enclosure. In my sims I include a summation node for the HP & LP outputs and the electrically summed node is anything but flat for the Altec Model 19 xover.
I can only anticipate Altec is aligning the phase of the drivers to produce an acoustically optimal system response? What else is there?

With respect to passive crossover components I have made a couple of measurement observations, I would like to share with the Forum.

I’ll start with a proposition: would you want a power amp with a dampening factor of < 20 and/or the THD > .5%? No, of course not!! Well, if the low-pass series inductor is not optimal the woofer will end up being driven by a low dampening factor and high distortion level. The HP crossover doesn’t have the dampening factor problem however the distortion can be excessive. So if I’m going to live with a passive crossover, what is the optimal inductor to minimize the inductor’s possible negative characteristics?

Inductor - World's Worst Passive Component?
In the article “Design of Passive Crossovers” by Rod Elleiot (http://sound.westhost.com/lr-passive.htm (http://sound.westhost.com/lr-passive.htm)) he wrote the inductor is the “World's Worst Passive Component”.

Given my observation there are two inductor characteristics that I want to minimize. Series DCR and inductor distortion caused by the core material. Even a small series DCR kills the dampening factor of a great amp and an inductor with a ferrite core will increase the distortion level to the woofer. These points are discussed in many articles however I have yet to see it quantified and would want it here from others that have tested crossover distortion. The dampening factor is the easy one to calculate but until now I was not aware of the distortion levels caused by the inductor cores. The dilemma, air core inductors are large, expensive, have the lowest distortion but the highest DCR while the ferrite/iron core inductors are less expensive, have the lowest DCR and the highest distortion.

Dampening Factor:
The low frequency (< 500Hz) dampening factor to the woofer is easy to calculate. For 20 ft of #14AWG speaker wire the DCR is .1 ohms and an Erse 2mH @ #14 AWG air core inductor has a DCR of .31 ohms. Therefore, the system dampening factor for the woofer with a nominal 8-ohm impedance will be < 19.5. If I desire a dampening factor of 40-50 the DCR budget for the combined speaker wire and crossover inductor is < .20 ohms. Given that 20 ft of 14 AWG speaker wire would limit the dampening factor to 80 and I desire to keep the dampening factor > 40 the crossover inductor is the dominate factor. To show that not all air-core inductors are created equal, the Jantzen 2.2mH @ 14 AWG Copper Foil Inductor has a DCR of .42 ohms. With the foil inductor the dampening factor would be < 16. The foil inductor’s larger DCR indicates the Jantzen #14 AWG foil design is not an optimal inductor without even discussing whether the foil design is useful at audio frequencies, since the additional DCR would indicate a greater wire length to develop the inductance value; (RE: DCR for #14 AWG non-foil inductor design). DCR is defined by the inductors wire gage and length. To optimize the inductance (minimize the wire length) the inductor would want to be fabricated by the dimensions of a Brooks coil. A Brooks coil of 2.2 mH @ 14 AWG inductor would have a DCR of .26 ohms. The link below describes the principles of a Brooks coil, “An introduction to the air cored coil” http://info.ee.surrey.ac.uk/Workshop/advice/coils/air_coils.html (http://info.ee.surrey.ac.uk/Workshop/advice/coils/air_coils.html). With #12 AWG magnet wire, (something I have yet to find readily available or in the Parts Express catalog, Solen has a 2.2 mH #12 AWG @ .24 ohms for $47 USD each) the Brooks coil designed 2.2 mH inductor should have a DCR of .18 ohms. The woofer dampening factor would now be on the order of 28. Increasing the speaker wire to #10 AWG, a reduction in wire DCR to .047 ohms, I can get the dampening factor above 35. This is where bi-amping shines, since the passive crossover DCR dominates the reduction in dampening factor and a bi-amped system would have a dampening factor of 170 with #10 AWG and an optimized passive crossover speaker system struggles to get to 40.

Inductor Distortion, P-Core :
The Jantzen P-Core inductors (I purchased several values to use in my crossovers) can substantially reduce the series DCR however the distortion created by the core material is not a desirable tradeoff, IMHO (I returned the P-Core - I wouldn’t use then after the THD discovery). To test the inductor distortion levels I did some simple comparative tests using a low-distortion Tek Sig-Gen (.002%) and a couple of Tek THD analyzers to measure inductor-induced distortion. My test circuit is a Crown D-75 driving the series inductor (DUT) 6dB/octave LP filter with a 10-ohm load. I used one analyzer to measure the amp THD and another to measure the THD across the 10 ohm load resistor. While my measurements are a single data point I anticipate most inductor core materials will perform with similar distortion levels as the P-Cores. I assume core material hysteresis is the culprit. The DUT is a 1.1 mH no-name air-core and a 1.0 mH Jantzen P-Core @ #15 AWG with a DCR of .09 ohms. The THD across the resistor measures a THD of .015% at –3dBV with air-core and with the Jantzen P-Core I measured a THD of .23% at –3dBV. Even at the lower less reactive frequencies the P-Core indictor had distortion levels of 5-10 times greater than the air-core inductor.

I also tested the inductors in an 18 dB/octave HP circuit configuration and the shunting P-Core inductor measures THD levels 2 times @ -3dBV and 5-6 times @ -10 dBV (@ 500Hz the THD was .93%) over the air core inductor.

My thoughts:
#14 AWG is not sufficient to maintain an adequate woofer dampening factor (especially if the speaker wire is of any length (I have speaker wires more then 40 ft) and the P-Core inductor adds significant distortion around the crossover point. If there is P-Core in the HP & LP filters then both drivers will be inducing distortion around the crossover point.

Arguments:
The difference between a dampening factor of 16 and 35 not audible in the LP filter and inductor induced THD levels of .25-.9% around the crossover point is lost in the overall speaker/room acoustics distortion levels?

Subjectively:
If I can measure it and the minimize artifact by simple selection of a specific component parameter then it is a worthwhile pursuit. Hence, I just purchased 900 ft of #12 AWG magnet wire and I will wind my own, Brooks coil design, air-core inductors; wish me well in this endeavor. I will report back on the results of the fabricated inductors.

I would like to hear from others that have made similar observations and/or measured other inductor cores with more favorable measurements supporting ferrite core inductors.