Here is another compression driver designed to go from 250hz - 2.5Khz useable to 3K
http://www.lansingheritage.org/images/jbl/specs/pro-comp/2490/page1.jpg
Rob🙂
http://www.lansingheritage.org/images/jbl/specs/pro-comp/2490/page1.jpg
Rob🙂
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Never seen that one, thanks!
How well do drivers like this really do at 300Hz? I was hard pressed to get much 300Hz out of my Altec 290 drivers on a 300Hz horn. Anyone else have experience with the JBL, EV and others like it? How is FR and distortion down at the low end?
How well do drivers like this really do at 300Hz? I was hard pressed to get much 300Hz out of my Altec 290 drivers on a 300Hz horn. Anyone else have experience with the JBL, EV and others like it? How is FR and distortion down at the low end?
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apparently cheap china driver can do in large enougf horn.
but from this it not becomes WE)))
in 2380 (night volum level 🙂):
but from this it not becomes WE)))
in 2380 (night volum level 🙂):
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The horn may be to blame. The 288-8G goes down to below 50Hz on a plane wave tube: http://alteclansingunofficial.nlenet.net/publications/techletters/TL_231.pdf
I've measured that myself too for 288B. The slight dip at around 300Hz disappears if you remove the back cover.
No PWT measurement for the 290-series drivers in the Technical Letter, though. But LF performance on the horn seems quite similar to the 288 driver, so there is a chance that the 290 could extend lower with the proper horn.
Regards,
Bjørn
Hi Kolbrek,
That is a very interesting Altec reference, with lots of good insight into the development of their drivers.
A comment on terminated tube measurements. These represent the units small signal response into a broad band resistive load. They may show response down to a fairly low frequency, but the manufacturer would never advocate that they be used that low! Much of this is dependent on the usual LF corner parameters of diaphragm mass and stiffness. None of these compression drivers have much excursion capibility and they were not intended to be used below 500Hz (300 for some paging units). Unless you like the sound of a diaphragm smacking the phase plug, I wouldn't try unfiltered voice through one except at very low level.
The horns will cut off at 500 to 800Hz or higher, dependent on size. Although you can design a larger unit and aim for a range down to say, 200, you would start to see compromises at the other end of the range. For example a low cut off means a lower flare rate and guarantees more HF beaming.
If the objective is natural voice, then 200 Hz isn't good enough for wide range male voice, you really need to get down to 100. Paging systems would worry about this because inteligibility is not lost with higher cut offs, just naturalness.
As I've mentioned before, once the cinema design norm became 2 way systems with larger woofers, it made more sense to optimize the horn compression drivers combos for a higher 500 Hz crossover and take the benefits at the upper cut off frequency. This gave the added benefit of allowing a short straight horn, to minimize depth loss behind the screen and further reduce the compromises forced by the need to fold or coil the horn.
David S.
That is a very interesting Altec reference, with lots of good insight into the development of their drivers.
A comment on terminated tube measurements. These represent the units small signal response into a broad band resistive load. They may show response down to a fairly low frequency, but the manufacturer would never advocate that they be used that low! Much of this is dependent on the usual LF corner parameters of diaphragm mass and stiffness. None of these compression drivers have much excursion capibility and they were not intended to be used below 500Hz (300 for some paging units). Unless you like the sound of a diaphragm smacking the phase plug, I wouldn't try unfiltered voice through one except at very low level.
The horns will cut off at 500 to 800Hz or higher, dependent on size. Although you can design a larger unit and aim for a range down to say, 200, you would start to see compromises at the other end of the range. For example a low cut off means a lower flare rate and guarantees more HF beaming.
If the objective is natural voice, then 200 Hz isn't good enough for wide range male voice, you really need to get down to 100. Paging systems would worry about this because inteligibility is not lost with higher cut offs, just naturalness.
As I've mentioned before, once the cinema design norm became 2 way systems with larger woofers, it made more sense to optimize the horn compression drivers combos for a higher 500 Hz crossover and take the benefits at the upper cut off frequency. This gave the added benefit of allowing a short straight horn, to minimize depth loss behind the screen and further reduce the compromises forced by the need to fold or coil the horn.
David S.
Maybe we need to take a step back and look at this in a different way. The design choices and solutions that were made were for theater systems, where wide, even coverage was more important than being able to play a large portion of the vocal range through a single driver.
Now, with the experience of the WE system, where even with compromised bandwidth and directivity some still prefer the sound, we ought to design a new driver/delivery system that can achieve similar targets. I'm thinking of some kind of hybrid driver/system that will have small size, high efficiency and reasonable directivity. Unless we change the fundamental design of these systems, we cannot solve the problem of high efficiency, large bandwidth, size and good directional properties. We can sacrifice are ideal polars and high power handling.
Is this totally impossible?
Now, with the experience of the WE system, where even with compromised bandwidth and directivity some still prefer the sound, we ought to design a new driver/delivery system that can achieve similar targets. I'm thinking of some kind of hybrid driver/system that will have small size, high efficiency and reasonable directivity. Unless we change the fundamental design of these systems, we cannot solve the problem of high efficiency, large bandwidth, size and good directional properties. We can sacrifice are ideal polars and high power handling.
Is this totally impossible?
Yes, such a system is certainly possible to implement with current-production parts.
But here's the catch:
I would bet $5 that no matter how close you got to matching every performance parameter of the WE system, if you sat people down in front of your creation and they saw it wasn't a beautiful old curly wood horn with a WE 555 driver on the skinny end, they would shake their heads and sadly inform you that it doesn't sound anywhere near as wonderful.
You would feel deeply exasperated. But if you're tempted to demand a blind listening test, bite your tongue. 🙂
Seriously, they would be right, and you would be wrong for one very important, very Zen reason: the sound we hear is never the sound we hear.
But here's the catch:
I would bet $5 that no matter how close you got to matching every performance parameter of the WE system, if you sat people down in front of your creation and they saw it wasn't a beautiful old curly wood horn with a WE 555 driver on the skinny end, they would shake their heads and sadly inform you that it doesn't sound anywhere near as wonderful.
You would feel deeply exasperated. But if you're tempted to demand a blind listening test, bite your tongue. 🙂
Seriously, they would be right, and you would be wrong for one very important, very Zen reason: the sound we hear is never the sound we hear.
Clearly, I have no idea how to achieve such a thing. But it seems like with current, or even 80 yr old horn-compression driver combos, it is impossible to fix the issue of size and crossing over to another driver. Basic performance parameters that we use to measure today's systems are not met. Tom's system certainly addresses some of these issues, but again use multiple drivers, albeit in a clever manner to achieve the trick.
Yes, you can of course not put much power into the driver at these low frequencies, even on a PWT (where the driver is resistance controlled over a quite large range, and displacement only doubles for each halving of frequency).
The 290 Giant Voice series were specified for 100W above 300Hz, and they have overhung voice coils. I'm sure they could be used for lower frequencies too, without much trouble, at home listening levels. 288B has more LF capability than later 288 versions, the spacing to the phase plug is larger. The cost is less HF extension, of course.
When I measured the 288B on PWT, I also tested various things, like running it at 1W input at 100Hz. It was not near hitting the phase plug, displacement as actually quite small (but visible). I also tried listening to the output of the measurement micrphone when playing music fullrange, and it sounded good, with tight, clean bass. Not something to try on a horn, of course...
Regards,
Bjørn
Something based on Danley's synergy-horn principle would certainly be in the top running if you were trying to create a system that behaves like one impossibly powerful, impossibly wideband driver with fewer (some would say different) compromises than the classic WE systems. But then hoping to make it sound like a WE system may be somewhat silly--again, mostly for reasons that are more biological than acoustical.
Some have mentioned harmonic integrity. How about designing the speaker system for minimal harmonic contribution (especially higher-order), and then feed it signal through a tubed preamp with a lovely euphonic harmonic signature. Viola: harmonic integrity top to bottom.
The only catch would be if you knew you had intentionally added harmonic distortion, the knowing would destroy for you an experience that would otherwise be glorious to a listener who was expecting to experience some pinnacle of aural nirvana.
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Hey Bjørn, the biggest horn I have is the Altec 803, which is said to be a 300Hz horn. Altec were pretty honest about that. I could get the 290 to play a little lower than the 288, but not much. Would be interesting to try it on a bigger horn - like the cool ones that Flaesh just posted.
Bill, I'd take that $5 bet. 🙂 The ALE, GOTO and similar "should" sound just as good, properly set up. Of course we could argue that price and reputation would skew the experience, but I've been down that road already (earlier in the thread).
Bill, I'd take that $5 bet. 🙂 The ALE, GOTO and similar "should" sound just as good, properly set up. Of course we could argue that price and reputation would skew the experience, but I've been down that road already (earlier in the thread).
Pano,
Touche! You're probably right about an ALE, GOTO system. Another legend to create a human auditory experience that transcends actual acoustics.
Good for you if you can hear through the hype. 99.2% of audiophiles bring more to the experience of listening to a legendary system than the system itself contributes.
...Or maybe bad for you that you can no longer suspend recognition of audible coloration. Perhaps, like me, you remember the joy you once felt when listening to "audiophile-grade" systems whose sonic warts are now jarringly obvious. Like first love, that's a state of being that's pretty close to impossible to recapture.
Touche! You're probably right about an ALE, GOTO system. Another legend to create a human auditory experience that transcends actual acoustics.
Good for you if you can hear through the hype. 99.2% of audiophiles bring more to the experience of listening to a legendary system than the system itself contributes.
...Or maybe bad for you that you can no longer suspend recognition of audible coloration. Perhaps, like me, you remember the joy you once felt when listening to "audiophile-grade" systems whose sonic warts are now jarringly obvious. Like first love, that's a state of being that's pretty close to impossible to recapture.
Dave Slagle had a really nice system going in his room at RMAF a couple years back. Big conical horn (IIRC) with a Lowther modified to field coil. Sounded terrific. The bass box did not do well in the room - too boomy - but the mids and highs were superb. It reminded me of the big, open relaxed sound of the W.E. gear. Never thought a Lowther could sound like that! 😉
We can be influenced by price, appearance, reputation, etc. - but those do not have to outweigh your own ears and judgment.
We can be influenced by price, appearance, reputation, etc. - but those do not have to outweigh your own ears and judgment.
the Altec drivers and similar are excursion limited by the surround/diaphragm edge. So, they can't make much output down low... and they will try to slap the phase plug too... that and a not a particularly flat response make them non-favs for moi.
I'm sorry, but I was never and have never been "wowed" by any high end or hi-fi stuff unless it just sounded way good, and very natural. There have only been a handful of systems that i can recall that made that mark - as in "gee I wish I could afford to own that..." And that included a wide range of almost everything sold for a very long time. Plus my hearing was better then than now, and then is now a fairly long time ago... so that encompasses a pretty broad spectrum of everything that has ever been out there. Transcendent sound just has to transcend, or else it doesn't. Does that make any sense?
Tom Danley, I sent you a PM here, check ur PM inbox??
_-_-bear
I'm sorry, but I was never and have never been "wowed" by any high end or hi-fi stuff unless it just sounded way good, and very natural. There have only been a handful of systems that i can recall that made that mark - as in "gee I wish I could afford to own that..." And that included a wide range of almost everything sold for a very long time. Plus my hearing was better then than now, and then is now a fairly long time ago... so that encompasses a pretty broad spectrum of everything that has ever been out there. Transcendent sound just has to transcend, or else it doesn't. Does that make any sense?
Tom Danley, I sent you a PM here, check ur PM inbox??
_-_-bear
my hearing was better then
But now we know better; that more is for morons. Thanks Red Skelton.
But now we know better; that more is for morons. Thanks Red Skelton.
It does. Absolutely.
And regardless of - or maybe because of - mechanical and material advances made since then, I believe we've lost so much of the nature of what transcendent sound is and its impact upon music as an experiential art-form.
Sonics is one thing. Musical enjoyment is another.
I'm not out to defend Western Electric particularly, but so many of the great pretenders that have "advanced" what's possible in domestic hi-fi since WE were making drivers and enclosures do nothing for me musically. And it's exactly in our musical enjoyment that I believe we've made the least progress.
Vinyl, tubes and compression drivers, in my experience, still deliver a far more visceral and immediate musical gestalt than do all the other topologies and derivatives invented since then. They're the only things that seem to consistently allow the medium to be transcended by the message.
I'm by no means a Luddite, but I do agree with whoever it was that said that a technology is often abandoned before it reaches its zenith. In that respect I believe the cultural legacy of WE is why compression drivers, horns, and tubes have forums dedicated to them on this very site.
Bite your tongue because a TEST is always a very different aesthetic and phenomenological experience than listening to music with a glass of wine in hand.
Musical audio is not a hearing test.
I don't entirely discount critical analytical listening, quick A-Bs, etc. We have to do this as part of system building. But that is not what a music listening system is for and not how a good system fits into our lives.
Not having heard the WE systems under discussion, it is easy to discount what I am calling the unique experience of listening to WE "Wide Range" systems. It is VASTLY different from everything else I've ever heard.
When jc morrison and I tested the 15A/woofer system we are taking to Munich...we burst out laughing. Joy, surprise, flat-out awesomeness. jc exclaimed" This is impossible!" HAHAHA! We are both used to playing with this stuff but it was still a powerful and shocking experience.
We put on Bach "Cantata and fugue in D Minor"...this is a corrnball audiophile test tune that neither one of us would ever play normally, except we wanted to check outthat organ bass. HAHAHA! Laughing our booties off. Yes, the bass was nuts but the whole sense of anticipation and majesty that big horn set up in an appropriate musical idiom, brought that bass note back to what it should have been all along...a totally overpowering awesome physical experience that opened the door to something transcendental.
The fact that the next door neighbor was there in 3 minutes to find out what the heck were were doing is about the sound. The fact that we were moved by the performance is about the music.
Is scrunched-up forehead high end weenie careful test listening appropriate or relevant? I say no, you won't get that far. This is not like comparing AC cords. This is visceral immediate big powerful musical experience.
I don't necessarily agree that WE fans would reject Satos and other such similarly scaled wide-bandwidth attempts. We'd be (and were and are) the first in line to sample them. In fact, WE fans are the ones doing this work.
Despite the obvious fetishism and focus on gear, and it is very impressive objet d'art equipment, the experience of music on these monsters is the thing that sets them apart.
One of the underlying factors that lead to the un-involving high-end speakers we are complaining about in this thread is the intellectualization fo the listening experience, in a way totally inconsistent with how we listen to enjoy music. The role of the "audiophile" became that of a mini-reviewer picking apart sound and complaining about the faults. It is a suspicious, hypercritical, mis-focused attitude that blows the fun and magic of music.
If that is too wishy-washy for scientists, that just tells me that we don't need that kind of science in that dimension of life. Stay in the lab and out of the room where we listen to tunes to enjoy and relax.
BTW: My conclusions are scientific...they come from anthropology, a social science. We are talking about people and culture here. FR sweeps and all that are good, but people engaged in certain human activities are the rest of "audio systems." People are in the system.