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Roddyama
09-22-2005, 03:19 PM
I'm looking for better mid-bass impact. This has been an ongoing quest for me for quite a number of years now. I wish to reproduce the crack of the snare drum. You know that sound. In real life, it makes you flinch and can almost be considered rude in how it imposes on you nervous system.

The range I need to cover is for 70-80Hz to 1200Hz (4 octaves). I currently using dual LE10A's per side in rebuilt Lancer boxes. I have either a NAD 2600 or Bryston 4B to drive them in my tri-amp setup. Below I am using TAD 1601a's in stereo bass boxes down to 28Hz (with electronic boost), and above I have TAD 4001's coupled to McCauley horn/lense combinations up to 12kHz where the 077's take over as super tweeters. See my avatar for my setup before I replaced the LE85's with the TAD's.

I sit about 3 to 4 m from the speakers in a room that is 4m wide and 7m long and has 3m ceilings. The speakers are toed in slightly 1m from the 4m long wall and each speaker is about 3/4m from the side walls.

I would like to find an alternative for the dual LE10A's in the mid-bass region. I am wondering how a short front horn might work in this situation. Any suggestion would be greatly appreciated.:barf:

Robh3606
09-22-2005, 03:54 PM
Well an E-145/2123 combo can do a good job. You get the flinch effect. Especailly if you don't know it's coming:D I run mine from 50Hz on up to 1.5K with a 300Hz crossover point between the two. The "C" Urei's run the 801C drivers a modified E-145 up to around 1k+ or so. Just a thought if you don't go horn. The E-145 is a very dynamic sounding driver.

Rob:)

jblnut
09-22-2005, 03:55 PM
The 108H in my 250Ti's really kicks ass in the snare drum region - it's one of my favorite aspects of the system. There might even be a newer/stronger replacement from the pro line which others could steer you towards.

jblnut



I'm looking for better mid-bass impact. This has been an ongoing quest for me for quite a number of years now. I wish to reproduce the crack of the snare drum. You know that sound. In real life, it makes you flinch and can almost be considered rude in how it imposes on you nervous system.

The range I need to cover is for 70-80Hz to 1200Hz (4 octaves). I currently using dual LE10A's per side in rebuilt Lancer boxes. I have either a NAD 2600 or Bryston 4B to drive them in my tri-amp setup. Below I am using TAD 1601a's in stereo bass boxes down to 28Hz (with electronic boost), and above I have TAD 4001's coupled to McCauley horn/lense combinations up to 12kHz where the 077's take over as super tweeters. See my avatar for my setup before I replaced the LE85's with the TAD's.

I sit about 3 to 4 m from the speakers in a room that is 4m wide and 7m long and has 3m ceilings. The speakers are toed in slightly 1m from the 4m long wall and each speaker is about 3/4m from the side walls.

I would like to find an alternative for the dual LE10A's in the mid-bass region. I am wondering how a short front horn might work in this situation. Any suggestion would be greatly appreciated.:barf:

RacerXtreme
09-22-2005, 06:38 PM
Why mess around. Get two of these. :blink:

http://www.mypages.iparenting.com/webs/racerxtreme/A1X.jpg

mikebake
09-22-2005, 06:47 PM
A front loaded horn can/will give you this. The startling impact of a snare or tom, etc. is indeed a stretch, if not totally out of reach, for many a speaker. A top notch pro-based direct radiator JBL driver can deliver it, but not IMO like a JBL horn loaded system. Whatever their drawbacks, a 4560 box can deliver the bulk of the drum range wtih impact and interesting clarity that damn few other boxes can. It is one of the (possibly few) things they seem to do particularly well. BTW, where, exactly, are you located? You might like to hear this response for yourself. Other JBl systems I've heard don't come close to what the (lowly) 4560 can do with drums. It's uncanny. A local 100 piece marching band actually goes by my house to practice; I invited the drum section to listen to some pieces; they were shocked at the transients/dynamics/power for the drums. My brother is an accomplished semi-pro drummer, product of North Texas State, still plays/practices 4 nights a week, recently performed with Steely Dan guitarist Elliott Randall (Reelin' in the Years), so he has a good appreciation for drum sound; only the 4560 has delivered the power for him. As Rob mentioned, E145-2123 are powerful enough and clean enough to give the effect, but horn loading adds a dimension hard to compete with.

mikebake
09-22-2005, 06:50 PM
Why mess around. Get two of these. :blink:


http://www.mypages.iparenting.com/webs/racerxtreme/A1X.jpgWell, yeah, kinda my point, really!

John
09-22-2005, 07:11 PM
Mike I think he is in Detroit!!! 8MILE RD.:applaud: Next to M+M:p

mikebake
09-22-2005, 07:18 PM
Mike I think he is in Detroit!!! 8MILE RD.:applaud: Next to M+M:pThat is what I was thinking; I can set up a really satisfying demo, but with a caveat; if you like the 4560 drum impact, they are not a "home-friendly" cabinet/size. He can also hear 4430/Performance Series/CS3115 systems for fun...............

RacerXtreme
09-22-2005, 08:09 PM
No, don't live in Dee - Troit. About an hour away - near Lake St. Clair.

Is space a problem?

http://www.mypages.iparenting.com/webs/racerxtreme/bighorns1.jpg

Roddyama
09-22-2005, 11:53 PM
Mike I think he is in Detroit!!! 8MILE RD.:applaud: Next to M+M:p
I'll have you know John, I'm north of 8mi road, in the 586.;)

Yes Mike, I'm in the Detroit area. I have been looking at the short front horns and wonder if they will still give me the 4 octave range I'm getting from the LE10A's now. Would I be getting the lowest octave through the port? The 4560 uses a 12" driver, correct? Is there a version that will use a 10" driver that you know of? How do voices sound using this type horn?

Sorry for the questions. Till from the diyAudio forum made a similar horn with an Altec driver with what seemed to be good success. But with him being in Germany, I'm sure I'll never get to hear them.:(

mikebake
09-23-2005, 05:30 AM
The 4560 is a mid-bass cabinet, and is pretty far down even at 60-80hz. It uses a 15 inch and is "fully horn loaded from 200hz up" to where it usually hands off to a comp. driver at around 1200. it is not a home hi-fi device, and carries some expected anomalies, but can sound qutie good on voice, and again, the impact of kick/tympani/toms is quite good. Excursion by the woofer at high output is reduced in the horn design, so distortion isn't bad.

Dr. Edgar has designed/produced/sold mid-bass horns for quite some time, with a good result. He sells the shells for a nice 80hz horn that is often paired with a JBL 12 incher, and also sells a horn loaded mid bass unit in the Titan system which used a 12. OVer this he generally used a 2440-41 unit and then a non-JBL tweet. The Titans are paired with his down firing Seismic sub, and across the range they are quite impressive overall. I'm still a big fan of the fully horn loaded 3-4 way designs for power and control. I think you'll find you need to go to something like that if you find you keep craving the impact.

p.s. in the Titan system Edgar uses his famous saladbowl round Tractrix mid horn with the 2441.

Earl K
09-23-2005, 05:55 AM
Hi Rodd,

FWIW ; the older alnico le10a(s) don't have as much "jump" factor as even the newer le10h models. The different magnets and the different coil types between the two are clearly audible ( to me at least ) . I can understand your comments about the le10a being too "polite" / though / I'm not sure I want to incorporate "rude" into my own listening experience . I do like Robs' terminology of "flinch factor" though I think I'd reserve that attribute for a HT system .


Baffle Mounting :

- Certainly baffle mounting something into a box ( sealed ) be the easiest approach to first try. That's what I would do . The minimal sawdust in this step is a good thing.

- Lancers suggestion of the 2122H ten makes a lot of sense. Given your parameters ; ( good down to 80 hz ) they will be the only JBL 10" that will have a chance at providing enough lowmid . The foam suspension is a very significant factor in allowing this 10" to operate that low . I do wonder if you are going to need 2 or 4 / considering what you presently listen to. 4 of these new is about $1000.00 . That has to be considered if this is a bit of a lark .

- 2206 & 2204 , 12" drivers are pretty common on eBay. It would be minimal financial risk to try a pair of these in boxes ( sealed is the first thing I'd try ) . Both these models have relatively high Qtc which I think is mostly caused by their stiff suspensions. I'd be inclined to loosen the suspension ( thus lowering Fs & Qtc ) and so creating a 12" version of the 2234 ( 15" ) . You'd need to do this mod. yourself with eBay foam kits ( if Rick Cobb can find some that fit ) .

-The Altec 414-8E ( ferrite magnet ) would be my first choice in 12s to try out . Unfortunately these only come up for sale on eBay less than once a year . Maybe Iconic makes a counterpart / haven't checked . If I'm not mistaken , these lighter coned , high compliance / low Fs woofers / use an underhung coil topology ( which will contribute to increased dynamics & accuracy ) . Likely worth checking out with Todd W.


Horn Loading :

See Volvotretters' Site (http://www.volvotreter.de/new_system.htm) for a good looking setup that incorporates horns into the living room .

- I think you are asking for too much range from a single horn-loaded driver . I'd email erik and ask him what he thinks .

- 140 or 150 hz is all you can expect from these sizes of horns . That limitation extends to the 4560. In the 4560, everything below the flare-cutoff ( I think @ 150 hz ) comes from the porting scheme .

- If you go the horn route, you'll be better off lowering the crossover point of your hi-mid horn.

- And while we are on the subject of change, get a pair of those large tractrix boat-horns that are just so clearly "superior" looking/sounding . :applaud:

<. EarlK

Roddyama
09-23-2005, 08:37 AM
Hi Earl,

If you ever sit front and center in a jazz club with an agressive drummer you'll know what I meant "rude".;) I don't expect to get exactly that from a set of speakers, but we're all here trying to do what we can.

I guess over the years I too have thought about or received suggestions about a number of variations. I like the idea of the short front horn but would not want to compromise the BW requirement. I have always felt it important that this band be spanned by a single driver. Particularly since my main use for these speaker are for music and HT being secondary.

Rob, I've thought about the 2123 and 12" combo. I like the idea. I would want to select the pair that would allow me to roll off the 12" response in the 300Hz range and let the 10" run the full range up to 1200Hz. All this driven by a single amp. Maybe this is the 2204 or 2206 coupled with the 2123 or 2122. with a little work I could fit them in my existing boxes. Making a separate chamber for the 10" wouldn't be too difficult.

I've also given a lot of thought to the full range guys. Im a little surprised no one has suggested this here yet. I believe it is the Lowther Opus the has a single driver front and rear horn loaded. Does anyone have any experience in this area? A couple years ago I heard the Rethm (sp?) full range speaker using, I believe, a Fostex driver. They sounded very good and the impact and dynamics were good as well.

My wife an I have separate condos so the SAF is not a factor at all. I have an end unit at the back of the complex and have run at very high levels without a complaint so I'm good to go on that count as well. I do tend to be a little on the pratical side when it comes to size though. A straight 70Hz Tractrix horn has always made me cringe no matter how much I try to talk myself into trying it.

Thanks all for your response so far.

P.S. I've drueled over the Volvotretters horns a few times:barf:

pangea
09-23-2005, 08:41 AM
- Roddyama
Nowhere in this thread, can I find anything on what kind of x-over you're using.

Since your drivers are housed in different cab's I think a couple of Behringer Ultradrive, DEQ or equivalent dbx Driverack x-overs, would help improving sound quality as well as mid-bass impact, when everything is properly time aligned and in phase.
Am I right?

I'm using the 2123 in my own speakers (see avatar) and I'm VERY impressed with how the snare- and kick- drum is presented, when the recording is good, that is.
I also think the class-D amps I'm using (Hypex UCD400), are equally instrumental in that improvment.

BR
Roland

Roddyama
09-23-2005, 10:32 AM
- Roddyama
Nowhere in this thread, can I find anything on what kind of x-over you're using.

Since your drivers are housed in different cab's I think a couple of Behringer Ultradrive, DEQ or equivalent dbx Driverack x-overs, would help improving sound quality as well as mid-bass impact, when everything is properly time aligned and in phase.
Am I right?

I'm using the 2123 in my own speakers (see avatar) and I'm VERY impressed with how the snare- and kick- drum is presented, when the recording is good, that is.
I also think the class-D amps I'm using (Hypex UCD400), are equally instrumental in that improvment.

BR
Roland

I'm currently using a Rane AC23 as a stand in for what will (at some point) be a customs crossover. I had a customized Heathkit xover for the low xover point. The upper xover point was a hybrid active/passive line level with a Nakamichi Black Box for the active portion. This began to malfunction a while ago so hence the Rane.

Crossovers were low LP @ 18db/oct @ 70Hz and low hp @ 6db/oct at ~90Hz. On the high xover it was 12db/oct @ 1250Hz for lp with a passive line level cap (6db/oct) hp @ 5kHz. This was to tame the lump in the response of the Radian diaphragm in the TAD 4001 driver.

I'm sure there is merit to physical time alignment and signal time alignment. I need to spend some time working on these issues. I first want to gether the right complement of drivers before I dive too deeply into that issues. Although I have not ignored it completely. The drivers and their application, I feel, will be the main factors to deal with.

mikebake
09-23-2005, 10:46 AM
[QUOTE=Roddyama]Hi Earl,

I've also given a lot of thought to the full range guys. Im a little surprised no one has suggested this here yet. I believe it is the Lowther Opus the has a single driver front and rear horn loaded. Does anyone have any experience in this area? A couple years ago I heard the Rethm (sp?) full range speaker using, I believe, a Fostex driver. They sounded very good and the impact and dynamics were good as well.

[QUOTE]

Lowther? Fuggedaboutit. Heard them in every manner of box and they can't do what a JBL driver can do for dynamic range/impact. Fullrange has too many compromises for my taste in a speaker that can deliver closer-to-life results. Ditto Fostex fullrangers. Fun, but falls short, needs sub, etc.

Roddyama
09-23-2005, 11:26 AM
[QUOTE=Roddyama]Hi Earl,

I've also given a lot of thought to the full range guys. Im a little surprised no one has suggested this here yet. I believe it is the Lowther Opus the has a single driver front and rear horn loaded. Does anyone have any experience in this area? A couple years ago I heard the Rethm (sp?) full range speaker using, I believe, a Fostex driver. They sounded very good and the impact and dynamics were good as well.

[QUOTE]

Lowther? Fuggedaboutit. Heard them in every manner of box and they can't do what a JBL driver can do for dynamic range/impact. Fullrange has too many compromises for my taste in a speaker that can deliver closer-to-life results. Ditto Fostex fullrangers. Fun, but falls short, needs sub, etc.

Mike,

Just to clarify my coments, I would only consider using the full range speaker in the 70Hz to 1200Hz band. With the BW limitation in mind, there may be other drivers that are better suited to this range that can be used in the BLH, or front and BLH configuration.

speakerdave
09-23-2005, 11:32 AM
A local 100 piece marching band actually goes by my house to practice . . . .
Damn! Some people have all the luck!

edgewound
09-23-2005, 11:45 AM
Hi Rod...


Here's another possible solution...You want attack of a snare drum...You have limited space. You need the most efficient compromise to get your intended result...An E120-8...or better yet 2...loaded into a 3-4 cubic foot box tuned to 60hz or so will give you lots of attack...in-your-face-attack. 2 E120-8 in one box at 4 ohms will give you about 109dB sensitivity to mate with whatever compression driver you choose. Here's the good part. I have NOS parts to build as-new, OEM style E120's....virgin speakers assembled by me...I'm JBL Authorized Service. $225.00 each. If you're interested, send me a PM and we can exchange contact info. BTW...I've got 2204's also...NOS

analogbass
09-23-2005, 11:57 AM
Get a used White or Urei EQ, adjust the mids to create that almost painful mid-chest impact.

mikebake
09-23-2005, 11:58 AM
Damn! Some people have all the luck!

When my parents lived here, my mom made a donation to the band and had them quietly assemble outside my dads bedroom window on his birthday at 6:55 a.m. and launch into a Sousa march to wake him up.........it was great, he loved it.

speakerdave
09-23-2005, 12:09 PM
Yeah, it's a great sound. I played trombone in a marching band when I was in school, and I put some marches on the stereo every once in a while.

Is anybody in your family a writer for "Curb Your Enthusiasm"?

David

(now back to the thread topic)

Don Mascali
09-23-2005, 12:38 PM
Hi Rod...


Here's another possible solution...You want attack of a snare drum...You have limited space. You need the most efficient compromise to get your intended result...An E120-8...or better yet 2...loaded into a 3-4 cubic foot box tuned to 60hz or so will give you lots of attack...in-your-face-attack. 2 E120-8 in one box at 4 ohms will give you about 109dB sensitivity to mate with whatever compression driver you choose. Here's the good part. I have NOS parts to build as-new, OEM style E120's....virgin speakers assembled by me...I'm JBL Authorized Service. $225.00 each. If you're interested, send me a PM and we can exchange contact info. BTW...I've got 2204's also...NOS

I have been using 2 E120s per side for years and they will knock you down. I run them 125 to 1250. They hand off to a B380 clone and a 4645C per side on the low and a 2246/2344 on the mid. There is a lot of punch.:D

Roddyama
09-23-2005, 12:45 PM
Hi Rod...


Here's another possible solution...You want attack of a snare drum...You have limited space. You need the most efficient compromise to get your intended result...An E120-8...or better yet 2...loaded into a 3-4 cubic foot box tuned to 60hz or so will give you lots of attack...in-your-face-attack. 2 E120-8 in one box at 4 ohms will give you about 109dB sensitivity to mate with whatever compression driver you choose. Here's the good part. I have NOS parts to build as-new, OEM style E120's....virgin speakers assembled by me...I'm JBL Authorized Service. $225.00 each. If you're interested, send me a PM and we can exchange contact info. BTW...I've got 2204's also...NOS

EW, I think the E120 would be a little over the top for me. However, my interest is renewed in the 12" + 10" per side idea. The 2204H at first look seems to be a possibility for the 12" driver. I'm thinking if I roll off its response at near the baffle step (say... 300Hz) and let the 10" work alone above that point to 1200Hz. The 10" would have to be of the same efficiency as the 12" but would work all the way down to the low cutoff at ~70Hz. I would need a single inductor in series with the 12" for the lp filter and it seems that 16ohm drivers in parallel might be best.

edgewound
09-23-2005, 01:06 PM
EW, I think the E120 would be a little over the top for me. However, my interest is renewed in the 12" + 10" per side idea. The 2204H at first look seems to be a possibility for the 12" driver. I'm thinking if I roll off its response at near the baffle step (say... 300Hz) and let the 10" work alone above that point to 1200Hz. The 10" would have to be of the same efficiency as the 12" but would work all the way down to the low cutoff at ~70Hz. I would need a single inductor in series with the 12" for the lp filter and it seems that 16ohm drivers in parallel might be best.

Hi Rodd...

I understand your concept. My position would be to keep your system as simple as possible by limiting the type of drivers...and filters,to get to your goal....Like Don previously mentioned the E120 will knock you down, and they are quite strong to 5khz! In the range you're considering, a pair of them would barely be breathing hard and would be extemely clean with gobs of headroom...not to mention the easy handoff to your 2" drivers. There's a much closer match to the sensitivities of the midbass and midrange that your amps will thank you for. If you construct your enclosure narrow enough with the dual 12's power response at the crossover frequency is minimized. All in all, the transient response and dynamic range with this setup would be tremendous. Thanks for reading my meanderings...:)

Roddyama
09-23-2005, 01:16 PM
Hi Rodd...

I understand your concept. My position would be to keep your system as simple as possible by limiting the type of drivers...and filters,to get to your goal....Like Don previously mentioned the E120 will knock you down, and they are quite strong to 5khz! In the range you're considering, a pair of them would barely be breathing hard and would be extemely clean with gobs of headroom...not to mention the easy handoff to your 2" drivers. There's a much closer match to the sensitivities of the midbass and midrange that your amps will thank you for. If you construct your enclosure narrow enough with the dual 12's power response at the crossover frequency is minimized. All in all, the transient response and dynamic range with this setup would be tremendous. Thanks for reading my meanderings...:)

How about dual E110's? These would be drop in replacements for my LE10A's. Will the E110's go down to 70Hz?

Lancer
09-23-2005, 01:24 PM
How about dual E110's? These would be drop in replacements for my LE10A's. Will the E110's go down to 70Hz?2122H or 2204H.

Earl K
09-23-2005, 03:58 PM
Rodd,

- Go with Lancers' suggestions for 2122H(s) .

- In all my years studying the readout of the Lansing Heritage tickertape, I've never come across anyone regretting the purchase of these tens .

- The fact is , JBL makes the best 10" drivers in the world .


:)

Steve Schell
09-24-2005, 12:14 AM
Roddyama, you have raised a very good question, and one that to me is at the very heart of good sound reproduction. Faithful reproduction of transients... "jump", "hit" or whatever you want to call it, is sorely lacking in most of what passes as high end (hind end?) sound gear.

One thing that is needed is adequate amplifier power and rise time to accurately trace steep transients. If you're going much above 100dB on peaks this takes a fair amount of power, even with highly efficient speakers.

If you check with an analyzer, I think that you'll find that the crack of a snare drum is mostly a midrange event, with energy concentrated from one to ten kHz. A compression driver on a good horn is what is needed to do this. Where many systems with compression mids fall down is in the lower frequencies, where the "dynamic linearity" for lack of a better term of the mid and lower bass does not keep pace with the mids. What we need is a system that tracks the signal dynamically as well as in frequency response over the entire audio bandwidth.

I have found in experiments over the past couple of years that compression drivers on appropriate horns to cover the full bandwidth can offer a new world of accuracy, though with complication in size, complexity and cost. Due to these factors, only a few small Japanese specialist companies have pursued this route. This is the frontier of sound reproduction, and I hope to see an increase in popularity, and a decrease in cost of this approach in the years ahead.

In general, I have found the accurate reproduction of dynamics to be tied more or less directly to speaker efficiency. What is needed is a light, stiff moving element, a powerful motor, and ideally horn loading to give the speaker every advantage in tracking the signal.

Roddyama, seems to me that your preferences will eventually lead you to a fully front horn loaded system. Have you had a listen to many of these?

Ian Mackenzie
09-24-2005, 01:23 AM
Rodd..its just old times,

"Rob, I've thought about the 2123 and 12" combo. I like the idea. I would want to select the pair that would allow me to roll off the 12" response in the 300Hz range and let the 10" run the full range up to 1200Hz. All this driven by a single amp. Maybe this is the 2204 or 2206 coupled with the 2123 or 2122. with a little work I could fit them in my existing boxes. Making a separate chamber for the 10" wouldn't be too difficult."

Yep, the LE10's are a tad too heavy and not the ideal choice to be running up to 1200hz. In fact based on recent tests with the 2122H directly bi amped it does ALL tricks (in a 4345) I think you are looking for and it will integrate seamlessly with the current horn you are using (per our previous discussions). Plus you don't have issue space and listening alignment issues that you have with mid horns (and 1 x 2122h per side is more than adequate!)


...ever thought about getting another Tad woofer and running them up to 300hz as a stereo pair.?.the whole affair should be more open and image better....(Tad woofer/2122/, 4001/2307/2308)

I also feel the whole mid bass thing is about alignment with transient capability much further up the scale..its the harmonics ovetones that make it work.

Playing for example The Eagles "Hell Freezes Over" on several tunes this type of transient is well heard.

You need a balance of bandwidth at both ends as well in the middle......the initial thud, the crack and the snap and then the pressure wake of low bass rolling out into the auditorium.

...was that transients we were talking about?

Might also be an idea to run your thoughts via Kent E

.

Roddyama
09-24-2005, 02:23 AM
Mike, It sounds like the 2122's would be a good step up for my system and toward my goal. Whether I would be satisfied with them, I couldn't say at this point. Ask me if I believe it to be the definitive answer and I'd have to say I don't think so. I had priced some 2123's a while back and almost ordered some from the JBL tent sale a couple years ago.

Steve, You have summed up my quest rather nicely, touching on what I believe the be the pertinent factors. As you can see by Ian's reply, we've talked about these issues before. Not just Ian an I but many from other forums.

Ian, Is it Deja Vous all over again or am I beating a dead horse? I have talked to Kent on this subject. You know he runs Altec front horns? He also like his TAD 1201's but hadn't really figured out how to integrate them yet, last I heard. BTW, I am using stereo 1601a's, they're just in separate boxes.

Well, you know I'm prone to fits of fantasy. I had a thought about scaling down (in frequency, up in size) the 077 defraction horns to a 70Hz cutoff but I think I need to read a lot more than I have on horn design.

Hmm,... how much for those 2122's?

"Duke" Spinner
09-24-2005, 02:54 AM
Roddyama, you have raised a very good question, and one that to me is at the very heart of good sound reproduction. Faithful reproduction of transients... "jump", "hit" or whatever you want to call it, is sorely lacking in most of what passes as high end (hind end?) sound gear.

One thing that is needed is adequate amplifier power and rise time to accurately trace steep transients. If you're going much above 100dB on peaks this takes a fair amount of power, even with highly efficient speakers.

If you check with an analyzer, I think that you'll find that the crack of a snare drum is mostly a midrange event, with energy concentrated from one to ten kHz. A compression driver on a good horn is what is needed to do this. Where many systems with compression mids fall down is in the lower frequencies, where the "dynamic linearity" for lack of a better term of the mid and lower bass does not keep pace with the mids. What we need is a system that tracks the signal dynamically as well as in frequency response over the entire audio bandwidth.

I have found in experiments over the past couple of years that compression drivers on appropriate horns to cover the full bandwidth can offer a new world of accuracy, though with complication in size, complexity and cost. Due to these factors, only a few small Japanese specialist companies have pursued this route. This is the frontier of sound reproduction, and I hope to see an increase in popularity, and a decrease in cost of this approach in the years ahead.

In general, I have found the accurate reproduction of dynamics to be tied more or less directly to speaker efficiency. What is needed is a light, stiff moving element, a powerful motor, and ideally horn loading to give the speaker every advantage in tracking the signal.

Roddyama, seems to me that your preferences will eventually lead you to a fully front horn loaded system. Have you had a listen to many of these?

actually, .......

i think you are wanting to emphasize the 1500 - 2500 hz range, if yer talkin' Snare "crack"

that'a all mid horn ...

man, do my Valencia's deliver, here ......;)

Jakob
09-24-2005, 06:03 AM
Hi!

What about the JBL 2227H? In a 140 litres cabinet tuned to 60Hz it's 3dB down att 70 Hz. And it is a very good sounding driver!

regards: Jakob

Ian Mackenzie
09-24-2005, 06:25 AM
Rodd,

Not really,

Change is not an easy thing when you have lived with a system for a time. I tend to look at these things from an idealised theoretical view point and assess what my drivers are doing well or not so well.....in this case the weak link is the LE10's. If you choked them back and run them from 70-300 it might work but that means a whole review of what you are doing.

I don't know much about your Tad woofers but I previously had doubts about running a JBL 2245H up to 290 hz fearing it would run out of puff( speed).

Not so, when bi amped and tuned correctly they really sing..GT really new what he was doing....and as a I said the effect of speed is lies in he harmonics and i doubt if the LE10 and working cleanly or accurately at the moment hence your desire to make a change.

I did hear Kents 4560's mod'd with rebuilt Altec woofers, damped and retuned cabinets and the damped 511's with the Tad2001 running Aleph 60's......damn near put me in a spin. Also I heard the Rushmore's barked up in Nelson's lounge room later in the evening and they were closer to the truth. They use a 10 inch PHL mid bass ..it was bliss.

Thus if you utlize the ultimate cone transducers which are 98 db + and run them tightly (piston mode) in their bassbands triamped I think the results with be nice without the risks of horns being horns.

The matter of compression drivers above 1000hz with wave guide benefits is a given.

There are some guys on the forums with a stash of stuff in limbo and they might offer a try before you buy the 2122/2123.

Ian

johnaec
09-24-2005, 07:17 AM
How would the 2012H compare here? (JBL's only listed component 10") Too much rising response?

John

Earl K
09-24-2005, 07:58 AM
How would the 2012H compare here? (JBL's only listed component 10") Too much rising response?



Forget the 2123 or 2121, they have too much motor to get down to 70 Hz, as does the 2202 (nothing wrong at all with those drivers when crossed over higher).

- As has been just said, when a person wants something that reaches below even 200 hz in a 10" , one needs to be looking at a high compliance surround that gives a low Fs ( like 40hz ) and a Qts figure that is complimentary to that Fs.
- The 2012 is a fantastic midrange performer ( lots of gap area with lots of magnet & a lot of voice coil winding length / all for a great BL figure ) but it unfortunately lacks the necessary high compliance surround to make it a contender for the minus 200hz range. Ported, it isn't bad to 110 hz.
- OTOH, there isn't anything stopping anyone from cutting out it's surround and installing a foam type to lower that Fs to a more usable figure . Buy Woofer Tester 2 before you go to the trouble, so that you know what you just created . :o:
-Because it has such a large motor , the cone would likely need some added weight/mass ( to re-establish the original Qts figure, after it dropped from the loosening of the compliance ).
- A stock 2012H should also have a custom LCR notch filter applied to flatten a problem in the 950 hz area ( though it's likely the previous mods would mitigate this bump somewhat / especially if the added weight was in the form of a cone dopping material , a la aquaplas ) .

- I use le10h(s) these days for mids because I really like their perfect pitch ( as RobH has poetically put it / it's the aquaplas don't you know ) . I have 2012s & 2123s setting around in boxes because they aren't foamed and more importantly aren't aquaplassed ;)

:p

Earl K
09-24-2005, 08:56 AM
Exactly. The 2122H is a least expensive approach that doesn't require a whole lot of effort to make it sound great. Bolt the bastard in and run with it. The other drivers require more effort and as we've stated, they can't go low without assistance.

Yeh, I just keep yakking to try to get the point across that the 2122H is the perfect solution ; following the KISS mantra ( no matter how it's sliced ). :p

tomt
09-24-2005, 09:18 AM
Roddyama -EW, I think the E120 would be a little over the top for me.
`````````````````````````````````````````````````` ```````
over the top?

not a bad thing really...
http://members.tripod.com/~BassPig

Titanium Dome
09-24-2005, 12:47 PM
Good Grief... that is so unbelievably unnecessary... that's what we commonly refer to as "fucking around". Been there, done that.

:rotfl:

His ten eighteen inch drivers and megawatt amps can kick your subwoofer's @ss, but I'll bet your TV is bigger. JFC, what's up with that? He ought to at least get a contractor in there and move that d@mn pole, although maybe he likes it there.




tomt: Just having a bit of fun. There's a lot of stuff in those pictures that I wish I had. :p

Titanium Dome
09-24-2005, 12:50 PM
Rodd: 2212H. Try it, you'll like it.

Roddyama
09-24-2005, 01:00 PM
ok, I'm convinced. I'll start with one 2122H per side. I'll run the parameters through BassBox later. Now I have to get the $500 together.

Zilch
09-24-2005, 01:44 PM
He ought to at least get a contractor in there and move that d@mn pole, although maybe he likes it there.Actually, we've analyzed this before. The pole is there specifically for the dancing.... ;)

edgewound
09-24-2005, 02:09 PM
If you're going to use an E120 then use an E110 instead. It can make it down to 70 Hz with a lot less effort. Rip out the aluminum dome and replace it with a paper dome.

Good Grief... that is so unbelievably unnecessary... that's what we commonly refer to as "fucking around". Been there, done that.

Rodd...

I can build you brand new E120's with a paper dome....just thought I'd add more confusion to the mix. Highest efficiency of all the suggestions...and effortless for your needs.

Lancer
09-25-2005, 06:44 AM
When you quote someone also include what they are referring to -




http://members.tripod.com/~BassPig

Good Grief... that is so unbelievably unnecessary... that's what we commonly refer to as "fucking around". Been there, done that.

Ian Mackenzie
09-25-2005, 07:03 AM
Looks more like an audio dooms day machine than something that would actually sound like real music!

Lancer
09-25-2005, 07:18 AM
I like that! - "an audio dooms day machine"

Well, it sounds to me like we need to drag a bunch of this stuff up to Rodd's house and give it all a listen. :p

Mrs Lansing
09-25-2005, 07:31 AM
I would make the trip if I were over there..Rodd's a hell of a nice guy!

pangea
09-25-2005, 07:56 AM
I'm currently using a Rane AC23 as a stand in for what will (at some point) be a customs crossover. I had a customized Heathkit xover for the low xover point. The upper xover point was a hybrid active/passive line level with a Nakamichi Black Box for the active portion. This began to malfunction a while ago so hence the Rane.

Crossovers were low LP @ 18db/oct @ 70Hz and low hp @ 6db/oct at ~90Hz. On the high xover it was 12db/oct @ 1250Hz for lp with a passive line level cap (6db/oct) hp @ 5kHz. This was to tame the lump in the response of the Radian diaphragm in the TAD 4001 driver.

I'm sure there is merit to physical time alignment and signal time alignment. I need to spend some time working on these issues. I first want to gether the right complement of drivers before I dive too deeply into that issues. Although I have not ignored it completely. The drivers and their application, I feel, will be the main factors to deal with.

With all those different slopes and with some cabs being vented and others being not vented, how do you keep track of all the phase-shifts and how do you know it isn't the x-overs that create the lump you mentioned?

BR
Roland

johnaec
09-25-2005, 08:53 AM
I like that! - "an audio dooms day machine"Now THIS looks like a JBL doomsday machine... http://cgi.ebay.com/JBL-BTX250-NEAR-NEW-AMP-SUBWOOFER-CAR-AUDIO-NO-RESERVE_W0QQitemZ5812723557QQcategoryZ18805QQrdZ1Q QcmdZViewItem

John

Roddyama
09-25-2005, 12:33 PM
Well, it sounds to me like we need to drag a bunch of this stuff up to Rodd's house and give it all a listen. :p


I would make the trip if I were over there..Rodd's a hell of a nice guy!

WOW, too nice. :o:

Roddyama
09-25-2005, 01:07 PM
With all those different slopes and with some cabs being vented and others being not vented, how do you keep track of all the phase-shifts and how do you know it isn't the x-overs that create the lump you mentioned?

BR
Roland
Actually Roland, it's not any more complex than any other 4 way system. Only the woofers are ported so the greatest phase shift is in the low cutoff region. The mid-basses are critically damped (Qt=.5) closed box so you're not going to get much less phase shift in any other system. The xover here is what used to be called (I think) "Minimum Phase" used by Dalquest and a few others back in the 70's and 80's. Basically a 18db/oct lp and a 6db/oct hp.

The bump in the response of the 4001's could be clearly heard. This was verified by Radian. The "hump" is very broad and extends the entire range of the driver from 600Hz to 15kHz with the center at about 3kHz at +12db referencing the -3db points at the ends (+15db to these points). The xover here is this cap plus a simple 12db X 12db butterworth. Again, this is far more simple than many xovers today.

Remember, you're going to get the phase shift regardless if the xover is a passive line level, full active, hybrid, or full passive hi-level. As i said before, I haven't put a lot of thought into time and phase alignment, but I have not ignored it either. Everything is in separate boxes/baffles so can be moved relative to one another easily. once I have the drivers I want, I will look more deeply into the phase issue.

P.S. Now with my older xover on the fritz, I've just put a Rane AC23 in place with has xover slopes of 24db/oct throughout. The initial listening is less then enthusiastic. :( I'will need to work more quickly toward my diy active xover which I'm gathering parts for now.

Dynacoman
09-25-2005, 01:10 PM
The short spelling for "Audio Doomsday Machine" is BOSE.:D

scott fitlin
09-25-2005, 01:16 PM
Rodd, do you have an original TAD diaphragm? It would be interesting to see if the original manufacturers part exhibits the same wide bump in the response!

Considering that the TAD 4001 is reknowned for its ultra superb clarity, efficiency, and flat response, I guess I would find the results from the radian diaphragm unacceptable. Of course, i also understand the TAD diaphragms are hellaciously expensive, but thats the route i`d go.

I have tried the radian replacements for my JBL 2441,s and stuck with JBL aluminum diaphragms.

Roddyama
09-25-2005, 01:33 PM
Rodd, do you have an original TAD diaphragm? It would be interesting to see if the original manufacturers part exhibits the same wide bump in the response!

Considering that the TAD 4001 is reknowned for its ultra superb clarity, efficiency, and flat response, I guess I would find the results from the radian diaphragm unacceptable. Of course, i also understand the TAD diaphragms are hellaciously expensive, but thats the route i`d go.

I have tried the radian replacements for my JBL 2441,s and stuck with JBL aluminum diaphragms.

I had the original TAD diaphrams when I bought the drivers. I cannot honestly say they had a fair listen from me as the system was in a state of flux when I first installed them and until they went south during some avoidable system glitches.:( Needless to say, I was very upset with loosing them and literally sent them south to a TAD dealer in FLA to experiment with as the beryllium domes were still intact. He was going to put a new experimental suspension on them.

The Radians actually sound good. The hp filter cap (theoretically) makes the response +-3db from 1kHz to 15kHz. I have no complaints about the Radian replacements which will take double the power to boot and cost 1/5 the cost of the TAD's.

scott fitlin
09-25-2005, 01:37 PM
I had the original TAD diaphrams when I bought the drivers. I cannot honestly say they had a fair listen from me as the system was in a state of flux when I first installed them and until they went south during some avoidable system glitches.:( Needless to say, I was very upset with loosing them and literally sent them south to a TAD dealer in FLA to experiment with as the beryllium domes were still intact. He was going to put a new experimental suspension on them.

The Radians actually sound good. The hp filter cap (theoretically) makes the response +-3db from 1kHz to 15kHz. I have no complaints about the Radian replacements which will take double the power to boot and cost 1/5 the cost of the TAD's.I hear you. I would have been upset at losing the TAD phragms myself.

Still, I would have liked to hear your thoughts on the TAD phragms, hearing them properly.

Roddyama
09-25-2005, 02:00 PM
I hear you. I would have been upset at losing the TAD phragms myself.

Still, I would have liked to hear your thoughts on the TAD phragms, hearing them properly.

My initial thoughts on the original TAD diaphragms was that they were very detailed but not dynamic enough, almost the point of being "laid back", but not quite. You could say, "smooth" but too smooth. Far too "polite" (Thanks for the word Earl;) ) for my tastes. It was very disconcerting for me as what I heard was totally unexpected having listened to the LE85's for 20 years. I was continually trying to find something I had done wrong in my setup. I believe, looking back, this may have added to the situation that ultimately caused their failure.

I don't know if you know this, but the TAD diaphragms and suspension are all one piece of beryllium. The voice coil former is bonded to the diaphragm/suspension. This is what makes them so fragile. I find it hard to believe the material used in the diaphragm because of its stiffness can be used in the suspension as well. It just goes against logic.

scott fitlin
09-25-2005, 02:11 PM
Yes, the TAD diaphragms are known to be delicate, and their cost makes it a prohibitive driver to use!

Its interesting you say you thought you did something wrong during setup, becuase you liked the JBL LE85,s better!

I bought TAD 4002,s to replace my JBL 2441,s, had been told by several to get the 4001, but the cost factor and TAD recommends the 4002 these days, so I bought! I also, spent a few weeks trying to figure out waht I wasnt doing right, then trying to get a sound I liked from the 4002,s, and then putting the 2441,s back, and finally accepting the fact the I like JBL!

I have heard the 4001,s and they are good, but there is a certain sound from those JBL drivers, crisp, sweet, and yes, DYNAMIC!

Cyclotronguy
09-26-2005, 09:28 AM
Hiya Rodd,

For what it's worth... my wife will not give up the TAD loaded JBL 4560's on the living room hi-fi / video system. If you can find the time to get out to California, come on up.

Cyclotronguy

Mr. Widget
09-26-2005, 09:40 AM
For what it's worth... my wife will not give up the TAD loaded JBL 4560's on the living room hi-fi / video system.

A wife like that is worth a lot!:bouncy:


Widget

Cyclotronguy
09-26-2005, 10:02 AM
Second time around was a charm. JBL 4560's were the second choice... we couldn't fit the horns she really wanted.

Cyclotronguy

Roddyama
09-26-2005, 12:15 PM
Hiya Rodd,

For what it's worth... my wife will not give up the TAD loaded JBL 4560's on the living room hi-fi / video system. If you can find the time to get out to California, come on up.

Cyclotronguy

Cyclotronguy's job description: Think of cool stuff and work on it.:D Than you have a wife that doesn't mind when you bring it home. Boy!, What a life.;)

I'm going to get out there to see you guys for sure next year, after the snow breaks.;) I'm also thinking about CES in Janurary. BTW, have you heard from your buddy, Paul B. lately. I'm courious to head how the TAD diaphragms turned out.

jandregg
09-26-2005, 12:56 PM
Rodd,

I am using the 2123j in a four way between an le-85 and le-15. The low frequency crossover is electronic and adjustable. The 2123 is in a seperate .5cu box crossed at 350hz and has a crisp response. I am near Newnan Georgia if your interested in hearing this setup. Bring your own cd.

John

Roddyama
09-26-2005, 01:32 PM
Rodd,

I am using the 2123j in a four way between an le-85 and le-15. The low frequency crossover is electronic and adjustable. The 2123 is in a seperate .5cu box crossed at 350hz and has a crisp response. I am near Newnan Georgia if your interested in hearing this setup. Bring your own cd.

John

Hi John,

Thank you for the offer. The problem I see with the 2123 is that it will not run down below 200Hz. I've modeled this a couple times with Bass Box which verified that situation. I need it torun down to 70Hz.

It sounds as if you have a 4343 type arrangement. Do you have any pictures? What are you using for the electronic X-over?

Tom Loizeaux
09-26-2005, 06:47 PM
Hi John,
... The problem I see with the 2123 is that it will not run down below 200Hz. ... I need it torun down to 70Hz.


I'm running a pair of 2123Hs in sealed boxes on each side of my small PA. I bring them in around 400Hz and take them out around 2.5K @ 18dB/Octave.
They sound great, but I'm not taking them anywhere near 70Hz!

It sounds to me as if you'll need 12 inch drivers in vented boxes to stay flat to 70Hz.
Just my guess.

Tom

jandregg
09-27-2005, 04:44 AM
"It sounds as if you have a 4343 type arrangement. Do you have any pictures? What are you using for the electronic X-over?"

Rodd

The lowest my crossover will go is 200hz. I ran the bottom end all the way down when testing without the crossover and in a .5cu box it doesn't go anywhere neat 70hz. However it adds a lot of snap to the sound of the 15 inch woofer. If you have heard the 4343 then you probably know. I've never actually heard the real thing.

John

Lancer
09-27-2005, 05:09 AM
I am using the 2123j in a four way between an le-85 and le-15. The low frequency crossover is electronic and adjustable. The 2123 is in a seperate .5cu box crossed at 350hz and has a crisp response.

I ran the bottom end all the way down when testing without the crossover and in a .5cu box it doesn't go anywhere neat 70hz. However it adds a lot of snap to the sound of the 15 inch woofer.

General post. Not directed at jandregg - The 2121 as used in the 4343 had a usable response in a 0.5 cu ft volume to ~ 75 Hz. The 2122 as used in the 4344/4345 had a usable response in a 0.5 cu ft volume to ~ 65 Hz. The 2123 as used in the 4344 Mk II had a usable response in a 0.5 cu ft volume to ~ 95 Hz. The smaller 112/2108 had a usable response in a 0.4 cu ft volume to ~ 65 Hz. Reference the L212 technical brief to see how JBL used the 112/2108 to 70 Hz, especially page 6 - http://audioheritage.org/vbulletin/showthread.php?t=4555. Invariably I used the 112/2108 for all direct radiator systems and the 2122 for systems incorporating compression drivers on the top end.

ralphs99
09-27-2005, 06:05 AM
I've got E110's that are pushed as low as they go. They're in a sealed enclosure with a cutoff near 125Hz. The 2nd order HPF thus formed comprises half of the crossover slope. From memory, in a sealed box, none of the 10" mids goes any lower.

It's also worth considering what a snare drum actually is: a diaphragm of about 15" diameter, tighly streched over a frame. When hit with a stick the diapragm moves about 1/4" at the centre. Basically a step response. The fundamental tone of a snare drum is thus in the region of 100-200Hz with loads of harmonics.

So I figure mid-bass impact comes from a relatively large diapragm mid-bass driver ~8-12" with a Qts suitable for sealed enclosures ~0.3, with low mass diaphrams ~30grams, and low voice coil inductance ~0.5. Hence my choice of the E110 over the 2122. (Availablity is another)

After living with the driver, the E110 wasn't as smooth as I would like, and doesn't go low enough. Part of the smoothness issue was resolved by replacing the dust cap with a paper version. The rest of the smoothness issue was taken care of with agressive notch filtering at around 5-6kHz. I cross to a 2344 at 1k3Hz but can still perceive the problems at 5-6kHz without the filters. But I still want the 10"ers to go lower, which they just can't do.

Interestingly, the LE10 has just the right set of parameters that I feel are most useful in a mid-bass driver. I would be keen to try some. But they're not so easy to find here in Oz, so I'm currently experimenting with some Volt 10" drivers.

I personally think it's worth perservering with your LE10's.

Start with the easy stuff first.

1. Check the spacing of your boxes from the walls. Watch out for cancellations in the region of 100-200Hz.

2. Check for room modes in the same frequency region.

3. Compensate for baffle step with some EQ.

4. Check for air leaks in your boxes.

5. Reduce the box volume by stuffing with solid objects.

6. Play around with the box stuffing.

7. Run an impedance plot on the individual drivers to see what the condition of the magnetic system and suspension is like. You may find that some maintenance work is in order.

8. Run an impedance plot on each box.

9. Then finally reach for the cheque book!

(Un)fortuntely with the marketing of rock music the way it is, one rarely hears a drum kit that actually sounds like a live kit. Real kick drums sound pretty loose. Real snare drums have way more attack than typical recording mediums can handle. We have to make do with what is presented to us in the recording. And usually that's not much....

Cheers,

Ralph.

Don Mascali
09-27-2005, 06:33 AM
We have to make do with what is presented to us in the recording. And usually that's not much...



Sometimes I think we forget this fact. With most of the systems we have here, The recording is the weakest link.

Lancer
09-27-2005, 06:37 AM
Nice post Ralph!

I've got E110's that are pushed as low as they go. They're in a sealed enclosure with a cutoff near 125Hz. The 2nd order HPF thus formed comprises half of the crossover slope. From memory, in a sealed box, none of the 10" mids goes any lower.

See my post above.

After living with the driver, the E110 wasn't as smooth as I would like, and doesn't go low enough. Part of the smoothness issue was resolved by replacing the dust cap with a paper version. The rest of the smoothness issue was taken care of with agressive notch filtering at around 5-6kHz. I cross to a 2344 at 1k3Hz but can still perceive the problems at 5-6kHz without the filters. But I still want the 10"ers to go lower, which they just can't do.

Yes, replacing the dust cap does help. Nice work on the notch filtering. What slope are you bringing in the bottom end at? I let the tens roll off naturally with just the 2nd order nature of the box providing the HP. I then add in the bottom end as desired/required for the specific room. For instance, the E110 might be 9 dB down at 70 Hz and a 2235H might be 9 dB down at 70 Hz but they sum to provide flat response depending on their physical placement. (See the L212 technical brief wherein each driver is ~ 9 dB down at crossover to provide a summed flat response)

Interestingly, the LE10 has just the right set of parameters that I feel are most useful in a mid-bass driver. I would be keen to try some. But they're not so easy to find here in Oz, so I'm currently experimenting with some Volt 10" drivers.

I personally think it's worth perservering with your LE10's.

The LE10H is a great driver. I stopped using the LE10A when the LE10H became available. Another issue with the LE10A (and 2121) is the inverted paper dome. It looks groovy but get rid of it and go with the LE10H/2122/2123 dome.

5. Reduce the box volume by stuffing with solid objects.

He should be at ~ 0.75 cu ft per LE10A right now. They shouldn't be sharing the Lancer 77 volume, they should be in their own volumes. If I remember correctly, and I'll be looking it up again in the near future, the LE10H likes ~ 1 cu ft of sealed volume.

You may find that some maintenance work is in order.

No doubt. The mags on those drivers are probably shot by now too. I'd go with SFG ferrites.

ralphs99
09-28-2005, 05:36 AM
Hey Lancer,

I'm currently using 125Hz as the crossover frequency from the E110's to the 2235. 4th order butterworth LPF and 2nd order HPF.

Just been having a look at the 218F. Could also be a very nice midbass driver. Only 8" but it's rated Xmax is 15mm! The smaller diameter would allow it to go higher too. Could be a good match for one of the new very short wave guides. They lose pattern control below a couple of kHz, so the 218F midbass could be a good fit crossing over at around 2kHz to match DI's.

Cheers,
Ralph.

Lancer
09-28-2005, 05:56 AM
Cool! I'll have a look as well. I'd be interested in a new 8-inch solution.

Roddyama
09-28-2005, 06:47 AM
Nice post Ralph!


The LE10H is a great driver. I stopped using the LE10A when the LE10H became available. Another issue with the LE10A (and 2121) is the inverted paper dome. It looks groovy but get rid of it and go with the LE10H/2122/2123 dome.

5. Reduce the box volume by stuffing with solid objects.

He should be at ~ 0.75 cu ft per LE10A right now. They shouldn't be sharing the Lancer 77 volume, they should be in their own volumes. If I remember correctly, and I'll be looking it up again in the near future, the LE10H likes ~ 1 cu ft of sealed volume.

You may find that some maintenance work is in order.

No doubt. The mags on those drivers are probably shot by now too. I'd go with SFG ferrites.

The ALNICO mags are one aspect I have paid much attention to. I guess I'll be pulling out the freq generator and retesting the parameters. I briefly looked at the 2122H's (post 2001 versions) and they don't seem to be usable below about 120Hz in a closed box. Not to say that this would be completely unacceptable. And there did seem to be some discrepencies in the parameters in BBPro. I will need to take a harder look at this.

The dual LE10A's are sharing the same closed box. This measured out ok some years back. Regardless, this will not have a large affect on the impact or dynamics of the driver(s), particularly in the small signal area.

Lancer
09-28-2005, 06:59 AM
Yes, the numbers in BB6P do seem jacked up for the 2122H. It also appears JBL changed the recone kit. I will be testing the latest recone kits in the near future. The 2122H's I refer to are from the 80's and they did indeed work. I used many, many of them.

The dual LE10A's are sharing the same closed box. This measured out ok some years back. Regardless, this will not have a large affect on the impact or dynamics of the driver(s), particularly in the small signal area.

Rest assured, it is best practice to give each transducer it's own volume. Common volumes are fine for SR applications, they are not really acceptable for high performance loudspeaker systems in the home environment.

tomt
09-29-2005, 11:57 AM
Zilch- Actually, we've analyzed this before. The pole is there specifically for the dancing....
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quite possibly, the most logical reason.......