ALtec Model 19-XO upgrade discussion

[Gary L]

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]

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.

[Zilch]

Too bad you can't pour water in it.

I've done that with packing peanuts a couple of times, actually.

[DaveV]

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]

Here are the plans

[Gary L]

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.

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]

Gary what about a design like this? Dual woofers

[Dylanl]

Back.

[Gary L]

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]

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]

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]

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]

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]

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]

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