" I'll grant that soft-dome tweeters are in breakup over much of their range as well, but that's a bit different - the damping goo spread onto the silk dome diffuses the resonances into a very fine-grained pattern"
The 435Be diaphrams are damped as well. They use aquaplas on them and the Aluminum 435Al used in the Performance Series. They are also using aquaplas on the newer Titanium drivers like the 2452SL
Rob
The 435Be diaphrams are damped as well. They use aquaplas on them and the Aluminum 435Al used in the Performance Series. They are also using aquaplas on the newer Titanium drivers like the 2452SL
Rob
OT, unhelpful and useless. This is from Francois Jullien's book "In Praise of Blandness":
"Such, then, is the bland sound: an attenuated sound that retreats from the ear and is allowed to simply die out over the longest
possible time. We hear it still, but just barely; and as it diminishes, it makes all the more audible that soundless beyond into which it is about to distinguish itself. We are listening, then, to its extinction, to its return to the great undifferentiated Matrix. This is the sound that, in its very fading, gradually opens the way from the audible to the inaudible and causes us to experience the continuous movement from one to the other. And as it gradually sheds its aural materiality, it leads us to the threshold of silence, a silence we experience as plenitude, at the very root of all harmony."
No "snappy transients" here.
Cilla
"Such, then, is the bland sound: an attenuated sound that retreats from the ear and is allowed to simply die out over the longest
possible time. We hear it still, but just barely; and as it diminishes, it makes all the more audible that soundless beyond into which it is about to distinguish itself. We are listening, then, to its extinction, to its return to the great undifferentiated Matrix. This is the sound that, in its very fading, gradually opens the way from the audible to the inaudible and causes us to experience the continuous movement from one to the other. And as it gradually sheds its aural materiality, it leads us to the threshold of silence, a silence we experience as plenitude, at the very root of all harmony."
No "snappy transients" here.
Cilla
Re: Center Speaker
See Us.Pat.#5610986 (via http://pat2pdf.org), and the following websites:
http://www.milestech.com
http://www.ampzilla2000.com/trinaural.html
You need an additional line level hardware and three amplifiers. A purely passive approach at speaker signal levels using xformers might be possible, but will be quite hard to construct it as a really good working solution.
I don't know if there are any drawbacks from using OB speakers, but maybe there are -- at least there are asymmtrical (in time) reflections because the distance to front/rear wall is not the same for all three speakers.
EDIT: **) there are some disadvantages with recording tricks (HTRF based phantom localization way beyond the speaker baseline, laterally and, to a lesser extent, vertically) that rely on the use of the conventional stereo triangle, for example "Q-Sound"
- Klaus
Regarding driving of a three speaker setup which still is "normal stereo" in the preceived sound (actually it is usually quite better -- gives a more convincing illusion -- than 2-speaker-stereo), you might want to try what is known as "optimum linear matrix" and, in a more specific form, "trinaural". Properly set up, there are no**) disadvantages except that you need some time to get accustomed to the new and somewhat different soundfield represention -- kind of similar to effect of boomy bass one has gotten so used to until the first OB speaker was heard... now one knows what "boomy" really means, and after hearing OLM you will know what "scattered" means...dobias said:
See Us.Pat.#5610986 (via http://pat2pdf.org), and the following websites:
http://www.milestech.com
http://www.ampzilla2000.com/trinaural.html
You need an additional line level hardware and three amplifiers. A purely passive approach at speaker signal levels using xformers might be possible, but will be quite hard to construct it as a really good working solution.
I don't know if there are any drawbacks from using OB speakers, but maybe there are -- at least there are asymmtrical (in time) reflections because the distance to front/rear wall is not the same for all three speakers.
EDIT: **) there are some disadvantages with recording tricks (HTRF based phantom localization way beyond the speaker baseline, laterally and, to a lesser extent, vertically) that rely on the use of the conventional stereo triangle, for example "Q-Sound"
- Klaus
"No "snappy transients" here."
So you like snare drums that sound like plastic paint pails and cymbals that sound like trash can lids??
"OT, unhelpful and useless."
Maybe to you. If you were considering using a compression driver in this application I wouldn't call the use of dampening material on the diaphragms as useless. What Lynn pointed out as a positive attribute with domes has the same effect with a compression driver diaphragm. The use of a layer of dampening material makes the 435Be even more unique. Very few compression drivers have any dampening materials used on the diaphragms. Any dampening becomes dependent on the self dampening characteristics of the material used or they way it was formed and the surround/compliance characteristics.
It makes a difference. The drivers with the aquaplas are smoother sounding than the ones without. It takes the harshness away from the drivers and opens the door to a lower cost option than the 435Be. If your are going to write off all Titanium compression drivers you should consider having a listen to one with a damped diaphragm before you do.
These newer throat-less drivers sound better than the last generation. No throat, neodymium magnets, new and improved phase plugs, modern waveguides and dampening all help. If you lump them with all the older drivers you will be the one stuck
"In Praise of Blandness"
Rob
So you like snare drums that sound like plastic paint pails and cymbals that sound like trash can lids??
"OT, unhelpful and useless."
Maybe to you. If you were considering using a compression driver in this application I wouldn't call the use of dampening material on the diaphragms as useless. What Lynn pointed out as a positive attribute with domes has the same effect with a compression driver diaphragm. The use of a layer of dampening material makes the 435Be even more unique. Very few compression drivers have any dampening materials used on the diaphragms. Any dampening becomes dependent on the self dampening characteristics of the material used or they way it was formed and the surround/compliance characteristics.
It makes a difference. The drivers with the aquaplas are smoother sounding than the ones without. It takes the harshness away from the drivers and opens the door to a lower cost option than the 435Be. If your are going to write off all Titanium compression drivers you should consider having a listen to one with a damped diaphragm before you do.
These newer throat-less drivers sound better than the last generation. No throat, neodymium magnets, new and improved phase plugs, modern waveguides and dampening all help. If you lump them with all the older drivers you will be the one stuck
"In Praise of Blandness"
Rob
Center speaker
Klaus,
Thank you very much for the information. As luck would have it, Mike Miles has his business a few hundred miles away here in Michigan.
I'll be in contact with him to work out the most inexpensive setup for me. I would like to have it work with my stereo amp but I'm willing to add an amp to have it work well.
It may be awhile before I can work it out but I'll let you know how it worked.
Do you have such an arrangement?
Frank
Klaus,
Thank you very much for the information. As luck would have it, Mike Miles has his business a few hundred miles away here in Michigan.
I'll be in contact with him to work out the most inexpensive setup for me. I would like to have it work with my stereo amp but I'm willing to add an amp to have it work well.
It may be awhile before I can work it out but I'll let you know how it worked.
Do you have such an arrangement?
Frank
Re: Center speaker
Not in an actual simple working condition (ahem, the 3rd identical speaker that is needed). But I have tested it thoroughly (I also tested/measured one of the hardware devices available), working up on the theory (which has some roots way back in time, see the papers of A.D.Blumlein, and, more recently, M.Gerzon) and investigating many possible arrangements with a DAW-Software (digital audio workstation) and a multiple output soundcard (I have 24 channels, no lack of channels therefore ;-). The hardest part was, because of not having three identical speakers, trying to make them "equal" (small active monitors and a conventional passive floorstander) by use of allpass filters to correct for the different xovers and of course some EQing to get at least first order aproximations of identical responses. While severly compromised by the dissimilar speakers, these tests were nevertheless extremly promising, and quite a few people have tested "the real thing" with the processor (J.B.'s) and 3 identical full-ranging speakers (which really is very important, the typical home-cinema center is often not sufficent). Not everyone would find himself satisfied with the difference in the stereo representation, but those who did will most certainly never switch back. The stable soundstaging even with considerable head movement/turn and the overall increase in "spatial resolution" by a percieved order of magnitude is really stunning (@naysayers, this is not marketing bla-bla, I have no relationship with any company or any other interest other than to promote all this because im really convinced of it, in theory and in practise. It's a just another way of projecting stereo information into the room, another reproduction paradigm).
Currently, I'm saving money for a bigger overall system upgrade and might meanwhile try some cheap single-driver OB's in that setup to test if there is any conflict -- as I'm a true fan of open baffle speakers I can only hope there isn't, no tradeoff to be considered then...
Perhaps one should start a seperate thread on this, it is quite OT here....
- Klaus
Hi Frank,dobias said:
Not in an actual simple working condition (ahem, the 3rd identical speaker that is needed). But I have tested it thoroughly (I also tested/measured one of the hardware devices available), working up on the theory (which has some roots way back in time, see the papers of A.D.Blumlein, and, more recently, M.Gerzon) and investigating many possible arrangements with a DAW-Software (digital audio workstation) and a multiple output soundcard (I have 24 channels, no lack of channels therefore ;-). The hardest part was, because of not having three identical speakers, trying to make them "equal" (small active monitors and a conventional passive floorstander) by use of allpass filters to correct for the different xovers and of course some EQing to get at least first order aproximations of identical responses. While severly compromised by the dissimilar speakers, these tests were nevertheless extremly promising, and quite a few people have tested "the real thing" with the processor (J.B.'s) and 3 identical full-ranging speakers (which really is very important, the typical home-cinema center is often not sufficent). Not everyone would find himself satisfied with the difference in the stereo representation, but those who did will most certainly never switch back. The stable soundstaging even with considerable head movement/turn and the overall increase in "spatial resolution" by a percieved order of magnitude is really stunning (@naysayers, this is not marketing bla-bla, I have no relationship with any company or any other interest other than to promote all this because im really convinced of it, in theory and in practise. It's a just another way of projecting stereo information into the room, another reproduction paradigm).
Currently, I'm saving money for a bigger overall system upgrade and might meanwhile try some cheap single-driver OB's in that setup to test if there is any conflict -- as I'm a true fan of open baffle speakers I can only hope there isn't, no tradeoff to be considered then...
Perhaps one should start a seperate thread on this, it is quite OT here....
- Klaus
Colorations
Most interesting. Much of the reason I'm on the verge of ordering a pair of Great Plains Audio 390 (new version of Altec 290) phenolic compression driver is the self-damping qualities of phenolic compared to metal diaphragms. (Yes, I'm aware the 290/390 requires a 14-ohm series resistor in combination with a 4-ohm VC in order to flatten it out so it can reach 7 kHz.)
I'm in the group that believes that high-Q ultrasonic resonances are not benign, and create crossmodulation products down in the audio band. Thus, a little bit of damping is a good thing, although not common in compression drivers. At times I wonder if some horn enthusiasts are expecting to hear the sound of metallic driver resonances, and associate that sound with "crispness" or "brightness". Playing massed choirs or violins - at realistic concert levels - usually exposes metallic resonances for what they are - harshness and breakup.
Rob, what's your take on the whole old vs new thing? I detest the sound of JBL CD horns in movie theaters, but I'm not going to blame the compression drivers for the defects of PA horns and appalling THX signal processing. All the things JBL is talking about in their tech papers - "throatless" compression drivers, selective diaphragm damping, and superior phase-plug design - all make for better time-domain response (while horns with kinks in the waveguide grossly degrade it).
I've never heard a modern JBL large-format compression driver on a Tractrix or LeCleac'h profile horn - just harsh-sounding theater and PA horns, where I thought they sounded pretty awful, distorted and very harsh, not even remotely suitable for acoustic music. But again, a bad horn can completely disguise the sound of an essentially perfect compression driver, so I can't draw any conclusion at all from what I heard.
Rob, which of the JBL 1.5" exit drivers have the modern technology - and what's your take on the sound when installed on Tractrix or LeCleac'h profile horn? Very curious about this.
Not a bad a idea to start a thread on high-quality 3-speaker stereo. I read Patent #5610986 carefully, and was dismayed to see no definition of the matrix itself, which is a crucial part of the invention. I hold three patents myself, and I know the patent office frowns on partial disclosure - trade secrets and patents are two different ways of protecting intellectual property, and are not to be commingled. I'm not a patent attorney, but that's what they told me. I was told to choose one of three methods: public disclosure in a magazine (creating prior art, thus precluding other patents), trade secrecy with rigorous NDAs for all concerned, and patenting - and not to mix them up.
The lack of disclosure of the 2 -> 3 matrix (which I noted was a static, not dynamic, matrix) makes it hard to tell from a straightforward Gerzon 2 -> 3 system, which dates back to the late Seventies. The Gerzon patents have all expired (along with my own, see #4018992), making them fully-disclosed prior art. I regret to say I do not see full disclosure in #5610986, which seems to invalidate the whole concept of patenting - there should be enough information in the patent so the device can be re-created by one "skilled in the art". Well, I see no mathematical coefficients, just vague descriptions of sum-and-difference networks - which are part of every matrix decoder without exception.
Actually, there's a fair amount of controversy of the correct way to derive the center channel, depending on the goals of the playback system. If the goal is to reduce the amount of comb-filter coloration of centered soloists (which is quite noticeable compared to monophonic single-speaker playback), it doesn't take much level to accomplish this - a phase and dispersion-matched Center speaker 12 dB down will do the job. If a smooth, equal-energy soundstage is desired, then more Center signal is required - but raising the level of the Center speaker also degrades the resolution of far-left or far-right signals due to crosstalk (the center signal is still present, and only a few dB down, when a L-only or R-only signal is on the recording).
This crosstalk is always there with any static matrix - which is why dynamic matrix systems were and are used for Sansui QS Vario-Matrix, Shadow Vector SQ, CBS Paramatrix SQ, Dolby Pro-Logic I, and Dolby Pro-Logic II. Once you go to dynamic playback matrices, of course, then the whole issue of image-shifting and maintaining constant reverberation energy raises its head - not to mention suitably-chosen attack and decay time constants for dynamic matrix (typically 1~3 mSec attack and 20~50 mSec decay).
Going back to static-matrix systems - which probably have the least coloration and odd-sounding dynamic artifacts - the requirement for phase, amplitude, FR, and dispersion-matching for every loudspeaker become quite severe, since there is never very much signal separation with any kind of input signal. With only 3~6 dB of separation between any pair of speakers - at the very most - then small differences between speakers become very important. Of course, even with full-discrete signals, it's still important, but only for the phantom images (and the reverberant content).
Robh3606 said:If you were considering using a compression driver in this application I wouldn't call the use of dampening material on the diaphragms as useless. What Lynn pointed out as a positive attribute with domes has the same effect with a compression driver diaphragm. The use of a layer of dampening material makes the 435Be even more unique. Very few compression drivers have any dampening materials used on the diaphragms. Any dampening becomes dependent on the self dampening characteristics of the material used or they way it was formed and the surround/compliance characteristics.
It makes a difference. The drivers with the aquaplas are smoother sounding than the ones without. It takes the harshness away from the drivers and opens the door to a lower cost option than the 435Be. If your are going to write off all Titanium compression drivers you should consider having a listen to one with a damped diaphragm before you do.
These newer throat-less drivers sound better than the last generation. No throat, neodymium magnets, new and improved phase plugs, modern waveguides and dampening all help.
Rob
Most interesting. Much of the reason I'm on the verge of ordering a pair of Great Plains Audio 390 (new version of Altec 290) phenolic compression driver is the self-damping qualities of phenolic compared to metal diaphragms. (Yes, I'm aware the 290/390 requires a 14-ohm series resistor in combination with a 4-ohm VC in order to flatten it out so it can reach 7 kHz.)
I'm in the group that believes that high-Q ultrasonic resonances are not benign, and create crossmodulation products down in the audio band. Thus, a little bit of damping is a good thing, although not common in compression drivers. At times I wonder if some horn enthusiasts are expecting to hear the sound of metallic driver resonances, and associate that sound with "crispness" or "brightness". Playing massed choirs or violins - at realistic concert levels - usually exposes metallic resonances for what they are - harshness and breakup.
Rob, what's your take on the whole old vs new thing? I detest the sound of JBL CD horns in movie theaters, but I'm not going to blame the compression drivers for the defects of PA horns and appalling THX signal processing. All the things JBL is talking about in their tech papers - "throatless" compression drivers, selective diaphragm damping, and superior phase-plug design - all make for better time-domain response (while horns with kinks in the waveguide grossly degrade it).
I've never heard a modern JBL large-format compression driver on a Tractrix or LeCleac'h profile horn - just harsh-sounding theater and PA horns, where I thought they sounded pretty awful, distorted and very harsh, not even remotely suitable for acoustic music. But again, a bad horn can completely disguise the sound of an essentially perfect compression driver, so I can't draw any conclusion at all from what I heard.
Rob, which of the JBL 1.5" exit drivers have the modern technology - and what's your take on the sound when installed on Tractrix or LeCleac'h profile horn? Very curious about this.
KSTR said:
Not a bad a idea to start a thread on high-quality 3-speaker stereo. I read Patent #5610986 carefully, and was dismayed to see no definition of the matrix itself, which is a crucial part of the invention. I hold three patents myself, and I know the patent office frowns on partial disclosure - trade secrets and patents are two different ways of protecting intellectual property, and are not to be commingled. I'm not a patent attorney, but that's what they told me. I was told to choose one of three methods: public disclosure in a magazine (creating prior art, thus precluding other patents), trade secrecy with rigorous NDAs for all concerned, and patenting - and not to mix them up.
The lack of disclosure of the 2 -> 3 matrix (which I noted was a static, not dynamic, matrix) makes it hard to tell from a straightforward Gerzon 2 -> 3 system, which dates back to the late Seventies. The Gerzon patents have all expired (along with my own, see #4018992), making them fully-disclosed prior art. I regret to say I do not see full disclosure in #5610986, which seems to invalidate the whole concept of patenting - there should be enough information in the patent so the device can be re-created by one "skilled in the art". Well, I see no mathematical coefficients, just vague descriptions of sum-and-difference networks - which are part of every matrix decoder without exception.
Actually, there's a fair amount of controversy of the correct way to derive the center channel, depending on the goals of the playback system. If the goal is to reduce the amount of comb-filter coloration of centered soloists (which is quite noticeable compared to monophonic single-speaker playback), it doesn't take much level to accomplish this - a phase and dispersion-matched Center speaker 12 dB down will do the job. If a smooth, equal-energy soundstage is desired, then more Center signal is required - but raising the level of the Center speaker also degrades the resolution of far-left or far-right signals due to crosstalk (the center signal is still present, and only a few dB down, when a L-only or R-only signal is on the recording).
This crosstalk is always there with any static matrix - which is why dynamic matrix systems were and are used for Sansui QS Vario-Matrix, Shadow Vector SQ, CBS Paramatrix SQ, Dolby Pro-Logic I, and Dolby Pro-Logic II. Once you go to dynamic playback matrices, of course, then the whole issue of image-shifting and maintaining constant reverberation energy raises its head - not to mention suitably-chosen attack and decay time constants for dynamic matrix (typically 1~3 mSec attack and 20~50 mSec decay).
Going back to static-matrix systems - which probably have the least coloration and odd-sounding dynamic artifacts - the requirement for phase, amplitude, FR, and dispersion-matching for every loudspeaker become quite severe, since there is never very much signal separation with any kind of input signal. With only 3~6 dB of separation between any pair of speakers - at the very most - then small differences between speakers become very important. Of course, even with full-discrete signals, it's still important, but only for the phantom images (and the reverberant content).
Hi Lynn,
Um, I'm a bit bewildered from your comments to be honest. I for one had no difficulty to find the required matrix formulae in the patent, albeit they are not written in classic matrix form. It's all right on the front page:
Lout = Lin - m*Rin
Rout = Rin - m*Lin
Cout = (1-m)*(Lin+Rin)
In the more general form one replaces (1-m) with another factor n and then we have all degrees of freedom in useful 2-to-3 linear revectorizing (as it is put sometimes). With these two factor I played a lot, and found, confirming the results of Mr.Miles and Mr.Bongiorno, that both factors at ~0.5 gives the best results (and, btw before I learned about the Miles patent). I also have two working circuits and some ideas for "high-end" circuit variations.
I know you were in the "matrixing business" and have serious expertise in these matters, so your comments are highly appreciated. I will collect the input from the last posts and start a new thread not to further pollute this one.
- Klaus
Um, I'm a bit bewildered from your comments to be honest. I for one had no difficulty to find the required matrix formulae in the patent, albeit they are not written in classic matrix form. It's all right on the front page:
Lout = Lin - m*Rin
Rout = Rin - m*Lin
Cout = (1-m)*(Lin+Rin)
In the more general form one replaces (1-m) with another factor n and then we have all degrees of freedom in useful 2-to-3 linear revectorizing (as it is put sometimes). With these two factor I played a lot, and found, confirming the results of Mr.Miles and Mr.Bongiorno, that both factors at ~0.5 gives the best results (and, btw before I learned about the Miles patent). I also have two working circuits and some ideas for "high-end" circuit variations.
I know you were in the "matrixing business" and have serious expertise in these matters, so your comments are highly appreciated. I will collect the input from the last posts and start a new thread not to further pollute this one.
- Klaus
I've extensively auditioned Bongiorno's Tri-naural processor in several good systems. Roger Waters' Ambisonics CD has that special wrap-around effect played back in stereo; in Tri-naural the sound field collapses into mush (only during the Ambisonic wrap-around effect).
Beyond the above problem the Tri-naural worked splendidly & probably would always be preferred over regular stereo playing non-Ambisonic software. Those familiar w/ the Waters CD may note the words are difficult to understand, even when played back on Yoav Geva's $96k Anat Reference. In Tri-naural on about $8k worth of speakers the words were crystal clear.
The Trinaural seemed best when used w/ a larger center speaker & smaller L/R (though all speakers employed similar drivers & technology). Above seemed even better even than all three same large speakers.
(OT: apologies...Bongiorno's $7500 Ambrosia SS is probably the best I've heard. Most appreciated are the transparent remote bass/treble w/ four xo poles each.)
Beyond the above problem the Tri-naural worked splendidly & probably would always be preferred over regular stereo playing non-Ambisonic software. Those familiar w/ the Waters CD may note the words are difficult to understand, even when played back on Yoav Geva's $96k Anat Reference. In Tri-naural on about $8k worth of speakers the words were crystal clear.
The Trinaural seemed best when used w/ a larger center speaker & smaller L/R (though all speakers employed similar drivers & technology). Above seemed even better even than all three same large speakers.
(OT: apologies...Bongiorno's $7500 Ambrosia SS is probably the best I've heard. Most appreciated are the transparent remote bass/treble w/ four xo poles each.)
Thread Forked
Discussion of 2 -> 3 channel stuff has been moved over here. Good comments, and no offense to the Trinaural folks intended. I encourage everyone to try 3 phase-matched speakers with a static-coefficient decoder some time - you might be surprised. Have fun playing with the decoding coefficients and center-speaker level - you can make dramatic changes in the perspective with small adjustments.
Discussion of 2 -> 3 channel stuff has been moved over here. Good comments, and no offense to the Trinaural folks intended. I encourage everyone to try 3 phase-matched speakers with a static-coefficient decoder some time - you might be surprised. Have fun playing with the decoding coefficients and center-speaker level - you can make dramatic changes in the perspective with small adjustments.
Center speaker
Klaus,
Maybe we ought to label the new thread "Pandora's Box".
I didn't realize I was opening it.
I had planned to use a third Wharfedale Super 12/CS/AL I have for the center. As dominant as they are, I couldn't imagine using anything else.
For what it's worth, the Ambisonics group believes it best to avoid a separate amplifier for the center channel.
dobias
PS: I, too, have had patents (that made fortunes for my employer).
I learned the only good patent is one that can withstand lawsuits.
I defended my patents for 5 years in Federal Courts. In fact I have the dubious distinction of having the last Federal trial , all the way to the Appeals Court, before Patent disputes were resolved by an arbitration board.
Klaus,
Maybe we ought to label the new thread "Pandora's Box".
I didn't realize I was opening it.
I had planned to use a third Wharfedale Super 12/CS/AL I have for the center. As dominant as they are, I couldn't imagine using anything else.
For what it's worth, the Ambisonics group believes it best to avoid a separate amplifier for the center channel.
dobias
PS: I, too, have had patents (that made fortunes for my employer).
I learned the only good patent is one that can withstand lawsuits.
I defended my patents for 5 years in Federal Courts. In fact I have the dubious distinction of having the last Federal trial , all the way to the Appeals Court, before Patent disputes were resolved by an arbitration board.
My first foray into commercial audio was the invention of the Shadow Vector SQ decoder - this idea was my ticket out of an unpleasant retail-sales job in Los Angeles, moving to Portland, Oregon, and working for Audionics. What a wild ride that was! The 2~3 years of developing the Shadow Vector prototype, meeting the bigwigs at CBS and demonstrating what a little Oregon company could do, was definitely worth it.
I was especially amused that the CBS team had to hire a professional mathematician to describe the operation of their Paramatrix - while I, the math dunce, the one that never got a decent grade in math in college, reduced the operation of the Shadow Vector down to 4 equations. The Scheiber-sphere figures 14 through 22 on the patent were the essential concept - the rest was a reduction to practice and building the thing. Surprisingly, the first time I heard it, it did sound like the sound I'd had in my head the whole time - spacious and clear, with smooth, natural reverberation all over the room.
I'm not sure the CBS team ever understood the concept of equal-energy decoding, which prevented the decoder from "hotspotting" and concentrating too much reverberant energy in any one area of the room. A very real risk for any dynamic decoder is optimizing too heavily for max separation at the speakers, while ignoring the stability and quality of the phantom images between the speakers. Unlike many other decoders, the Shadow Vector had equal separation for all directions, phantom or not. Dolby Pro-Logic I had a problem with "detenting", for example, while Pro-Logic II in "music" mode is greatly improved - although the energy distribution still doesn't sound completely even to me.
Even though quadraphonic never went anywhere, it was a fun ride while it lasted - and the experience came in handy for designing loudspeakers. Since I'd spent 2~3 years on a system that was designed to have smooth distribution of reverberant energy - while maintaining crisp localization - the key concepts were just carried forward.
I was especially amused that the CBS team had to hire a professional mathematician to describe the operation of their Paramatrix - while I, the math dunce, the one that never got a decent grade in math in college, reduced the operation of the Shadow Vector down to 4 equations. The Scheiber-sphere figures 14 through 22 on the patent were the essential concept - the rest was a reduction to practice and building the thing. Surprisingly, the first time I heard it, it did sound like the sound I'd had in my head the whole time - spacious and clear, with smooth, natural reverberation all over the room.
I'm not sure the CBS team ever understood the concept of equal-energy decoding, which prevented the decoder from "hotspotting" and concentrating too much reverberant energy in any one area of the room. A very real risk for any dynamic decoder is optimizing too heavily for max separation at the speakers, while ignoring the stability and quality of the phantom images between the speakers. Unlike many other decoders, the Shadow Vector had equal separation for all directions, phantom or not. Dolby Pro-Logic I had a problem with "detenting", for example, while Pro-Logic II in "music" mode is greatly improved - although the energy distribution still doesn't sound completely even to me.
Even though quadraphonic never went anywhere, it was a fun ride while it lasted - and the experience came in handy for designing loudspeakers. Since I'd spent 2~3 years on a system that was designed to have smooth distribution of reverberant energy - while maintaining crisp localization - the key concepts were just carried forward.
Hello Lynn
“I detest the sound of JBL CD horns in movie theaters, but I'm not going to blame the compression drivers for the defects of PA horns and appalling THX signal processing.”
I have heard some really terrible sounding installations as well. I have also been in the same venue for both acoustic and electric bands and had some real eye opening experiences there. Saw the acoustic show first with guitars and vocal with some drums. I was surprised just how good that PA sounded. Went back for another show with high hopes and it sounded just awful. I was amazed it could sound that bad after seeing the previous show.
Actually in Pro and Cinema applications I think it’s a combination of both the drivers and the horns. I think Earl Geddes is on to something with his waveguides designed to minimize the effects of HOM modes in the horns. From what I have read the audibility of HOM is dependent on SPL.
In that application you have worst case conditions with both HOM and the compression drivers. If you look what CD compensation is doing you are adding between 6-10Db of active compensation so you power input is between 4 to 10 time greater right in the region where these diaphragms are in these various break-up modes.
If you look at what happens in a typical home installation it’s apples and oranges. At home we can use a passive network for CD compensation to attenuate the midband response. This reduces both the diaphragm excursions in the compression driver and avoids dumping power into the drivers above the 5K and up range. I most cases depending on what the woofer sensitivity is you would be lucky to be using more than several watts of power. You will be well below the drivers power rating and excursion limits.
With the reduced SPL’S the HOM are not as audible and may be below your tolerance threshold for them. I have pushed some horns at home and sure enough you get past a certain point and it gets nasty for lack of a better word. At the typical lower SPL’s used for home listening I thought they sounded good. By typical my average is about 85db where I sit but I have the capability to hit a clean 115db on peaks so I have 30db of available headroom above the average. That headroom makes a big difference on drums, horns, and percussion IMHO.
I don’t think it’s a fair assessment of what performance you can get using Pro applications as a reference. I think that the potential is there for horns and compression drivers to offer better performance in a home installations than we typically hear when used in Pro sound applications.
Rob
“I detest the sound of JBL CD horns in movie theaters, but I'm not going to blame the compression drivers for the defects of PA horns and appalling THX signal processing.”
I have heard some really terrible sounding installations as well. I have also been in the same venue for both acoustic and electric bands and had some real eye opening experiences there. Saw the acoustic show first with guitars and vocal with some drums. I was surprised just how good that PA sounded. Went back for another show with high hopes and it sounded just awful. I was amazed it could sound that bad after seeing the previous show.
Actually in Pro and Cinema applications I think it’s a combination of both the drivers and the horns. I think Earl Geddes is on to something with his waveguides designed to minimize the effects of HOM modes in the horns. From what I have read the audibility of HOM is dependent on SPL.
In that application you have worst case conditions with both HOM and the compression drivers. If you look what CD compensation is doing you are adding between 6-10Db of active compensation so you power input is between 4 to 10 time greater right in the region where these diaphragms are in these various break-up modes.
If you look at what happens in a typical home installation it’s apples and oranges. At home we can use a passive network for CD compensation to attenuate the midband response. This reduces both the diaphragm excursions in the compression driver and avoids dumping power into the drivers above the 5K and up range. I most cases depending on what the woofer sensitivity is you would be lucky to be using more than several watts of power. You will be well below the drivers power rating and excursion limits.
With the reduced SPL’S the HOM are not as audible and may be below your tolerance threshold for them. I have pushed some horns at home and sure enough you get past a certain point and it gets nasty for lack of a better word. At the typical lower SPL’s used for home listening I thought they sounded good. By typical my average is about 85db where I sit but I have the capability to hit a clean 115db on peaks so I have 30db of available headroom above the average. That headroom makes a big difference on drums, horns, and percussion IMHO.
I don’t think it’s a fair assessment of what performance you can get using Pro applications as a reference. I think that the potential is there for horns and compression drivers to offer better performance in a home installations than we typically hear when used in Pro sound applications.
Rob
Hmm - probably because of my previous work in quadraphonics and low-diffraction loudspeaker design, I may have sensitized myself to loudspeaker artifacts that damage the stereo perspective and perception of ambient impression. Much of the work on Shadow Vector was focussed on retaining the ambient impression without distortion (truncation, fluttering sensations, what we call "front-to-back depth" but over the whole 360 playback arc). If the venue was large, it had to sound that way, and without "detenting" effects or shadowing (portions of the room that lacked depth). Most other quadraphonic decoders had almost no sensation of depth at all, or a very unnatural perspective that was "speaker-centric". Since a lot of monitoring was done on pro monitors with very poor depth rendition (but good dynamics) the recordings themselves could be quite variable.
The same applied to my later work at Audionics. I was firmly in the Brit-school of design, with an emphasis on the work of D.E.L. Shorter of the BBC and Laurie Fincham at KEF. Meeting them in 1975, and hearing BBC experimental quadraphonic mastertapes, left a strong impression which has influenced what I do to this day. The construction of a very low diffraction experimental speaker at Audionics (it looked like a big vitamin pill) in 1979 also left a strong impression - reduce diffraction enough, and the speaker effectively disappears. Increase the diffraction, there is more sensation of a distinct speaker-shaped sound source in the room, increase the diffraction some more, and soundstage "detenting" becomes apparent, center and part-center phantom images become diffuse, depth impression gradually diminishes to zero, and then, in the most severe cases, gross mid and upper-mid colorations become obvious - particularly with singers and massed chorus.
Some of this sensitivity must be individual - I can listen to systems that have gross amounts of diffraction and diffraction-related colorations, and other listeners in the same room are thrilled and rave about the "depth" and "realism" - and I hear no depth, no realism, and lots of tin-can and megaphone-like coloration. I've yet to hear a conical horn, for example, that doesn't have unacceptable levels of diffraction and mid-coloration - maybe they're out there, just haven't heard one for myself. By contrast, the Dr. Geddes and LeCleac'h waveguides that I've heard to date sound completely different - open, natural, and very little horn coloration.
What dismays me about CD horns is the intentional diffraction inside the horn - what I call a "kink" in the flare rate. Since horns already suffer from mouth diffraction and strong reflections off the hard surface of the phase-plug, adding an additional diffracting surface inside the middle of the horn just seems to be asking for trouble. This kind of trouble is very obvious in impulse-response measurements, but for reasons that must be historical, impulse measurements are very rarely used in the professional world.
I'm especially pleased that both Dr. Geddes and LeCleach'h are looking into time-domain performance for waveguide and horns. One of the more frustrating "could-have-beens" was that Dick Heyser (of TDS fame) published his first work in the early Seventies, and lived in Los Angeles. LA is a JBL/Altec company town, and these two industry-leading companies did their best to ignore him - "Not Invented Here".
If there had been less NIH attitude from JBL and Altec, we could have had horns with good time-domain performance for the last 35 years - and CD horns may have taken a very different direction. I think it reveals something that impulse response data on horns is still very difficult to find from the world's largest vendor of professional systems - 15 years after MLSSA became the industry standard for measurement - and impulse response is the very first measurement you see on the screen when MLSSA data is captured.
The same applied to my later work at Audionics. I was firmly in the Brit-school of design, with an emphasis on the work of D.E.L. Shorter of the BBC and Laurie Fincham at KEF. Meeting them in 1975, and hearing BBC experimental quadraphonic mastertapes, left a strong impression which has influenced what I do to this day. The construction of a very low diffraction experimental speaker at Audionics (it looked like a big vitamin pill) in 1979 also left a strong impression - reduce diffraction enough, and the speaker effectively disappears. Increase the diffraction, there is more sensation of a distinct speaker-shaped sound source in the room, increase the diffraction some more, and soundstage "detenting" becomes apparent, center and part-center phantom images become diffuse, depth impression gradually diminishes to zero, and then, in the most severe cases, gross mid and upper-mid colorations become obvious - particularly with singers and massed chorus.
Some of this sensitivity must be individual - I can listen to systems that have gross amounts of diffraction and diffraction-related colorations, and other listeners in the same room are thrilled and rave about the "depth" and "realism" - and I hear no depth, no realism, and lots of tin-can and megaphone-like coloration. I've yet to hear a conical horn, for example, that doesn't have unacceptable levels of diffraction and mid-coloration - maybe they're out there, just haven't heard one for myself. By contrast, the Dr. Geddes and LeCleac'h waveguides that I've heard to date sound completely different - open, natural, and very little horn coloration.
What dismays me about CD horns is the intentional diffraction inside the horn - what I call a "kink" in the flare rate. Since horns already suffer from mouth diffraction and strong reflections off the hard surface of the phase-plug, adding an additional diffracting surface inside the middle of the horn just seems to be asking for trouble. This kind of trouble is very obvious in impulse-response measurements, but for reasons that must be historical, impulse measurements are very rarely used in the professional world.
I'm especially pleased that both Dr. Geddes and LeCleach'h are looking into time-domain performance for waveguide and horns. One of the more frustrating "could-have-beens" was that Dick Heyser (of TDS fame) published his first work in the early Seventies, and lived in Los Angeles. LA is a JBL/Altec company town, and these two industry-leading companies did their best to ignore him - "Not Invented Here".
If there had been less NIH attitude from JBL and Altec, we could have had horns with good time-domain performance for the last 35 years - and CD horns may have taken a very different direction. I think it reveals something that impulse response data on horns is still very difficult to find from the world's largest vendor of professional systems - 15 years after MLSSA became the industry standard for measurement - and impulse response is the very first measurement you see on the screen when MLSSA data is captured.
Rob, which of the JBL 1.5" exit drivers have the modern technology - and what's your take on the sound when installed on Tractrix or LeCleac'h profile horn? Very curious about this.
Hello Lynn
I split my reply to keep the post from going too long. The only JBL compression drivers I have heard on a tractix were reconditioned 2441’s listening to Bruce Edgars Titans. I liked them quite a bit.
For a 1.5” throat you would have 2430/2431/2435/2451 and 2452
The only modern drivers I have used from the current crop are the 2431 and 2435’s which have consumer equivalents in the 435AL and 435Be. The difference between the Vertec and the Consumer versions are the backcap and aquaplas used on the consumer versions. Other than that they are identical.
I was using a 2344A horn with a 2425 1” compression driver. Standard 80’s issue in the 4430/4435 monitors. Classic CD design with a diffraction slot with sharp transitions. That’s the horn used in Earls blind comparison testing for his Suma speakers. The only difference from stock was I had an aquaplas damped Ti diaphragm installed. I was happy with them for a couple of years. At the levels I normally listen at they sounded fine to me.
When 2435’s started showing up on E-bay I took the leap and purchased a pair. All you normally need to do with these is clean the gaps replace the Ferro run impedance plots and a quick measurement and you are good to go. One of that drivers main advantage as you know is freedom from the break-up modes present in the older Titanium drivers. I mated them up with the PTH 1010 Waveguide which are one of JBL’s newest waveguides.
The horn/waveguides are identical as far as coverage pattern, size, and frequency range in my application. I could just swap them into my existing set-up. The compensations had to be changed so I had to build networks but other than that only a change in level was required to drop them in.
I made the switch and was pleasantly surprised. The newer driver and waveguide was simply a better sounding combination. They were better in every way. I would encourage anyone looking at compression drivers to have a listen to the newer drivers. Not just JBL, any that are using newer phase plug designs or to try the newer waveguides on older drivers. If I was running 1" drivers I would be looking real hard at Earls waveguides.
Rob
Hello Lynn
I split my reply to keep the post from going too long. The only JBL compression drivers I have heard on a tractix were reconditioned 2441’s listening to Bruce Edgars Titans. I liked them quite a bit.
For a 1.5” throat you would have 2430/2431/2435/2451 and 2452
The only modern drivers I have used from the current crop are the 2431 and 2435’s which have consumer equivalents in the 435AL and 435Be. The difference between the Vertec and the Consumer versions are the backcap and aquaplas used on the consumer versions. Other than that they are identical.
I was using a 2344A horn with a 2425 1” compression driver. Standard 80’s issue in the 4430/4435 monitors. Classic CD design with a diffraction slot with sharp transitions. That’s the horn used in Earls blind comparison testing for his Suma speakers. The only difference from stock was I had an aquaplas damped Ti diaphragm installed. I was happy with them for a couple of years. At the levels I normally listen at they sounded fine to me.
When 2435’s started showing up on E-bay I took the leap and purchased a pair. All you normally need to do with these is clean the gaps replace the Ferro run impedance plots and a quick measurement and you are good to go. One of that drivers main advantage as you know is freedom from the break-up modes present in the older Titanium drivers. I mated them up with the PTH 1010 Waveguide which are one of JBL’s newest waveguides.
The horn/waveguides are identical as far as coverage pattern, size, and frequency range in my application. I could just swap them into my existing set-up. The compensations had to be changed so I had to build networks but other than that only a change in level was required to drop them in.
I made the switch and was pleasantly surprised. The newer driver and waveguide was simply a better sounding combination. They were better in every way. I would encourage anyone looking at compression drivers to have a listen to the newer drivers. Not just JBL, any that are using newer phase plug designs or to try the newer waveguides on older drivers. If I was running 1" drivers I would be looking real hard at Earls waveguides.
Rob
Hello Magnetar
"Isn't aquaplas just latex paint?"
No not at all. It's now called AntiVibe but still made by the same company. It's been around for quite some time. The white coating on the 4310/4311/L100 woofers and the LE-14 is Aquaplas/Antivibe. Do a search and you will get plenty of industrial supply house links. It used to damp ductwork and many other sound related applications.
I have a sample and it's a heavy paste that flows under preasure. In most applications it gets sprayed on. You can see the silica fillers in it. When it dries it's a matte finish with a "sparkles".
Tried doing some home grown experiments with it before and after. I will take a look to see if I have the CSD plots. It was a real head scrather. Reminds me of the Enable thread. One of those I know it's doing something
I can hear it
, now go and find what it is.
Rob
"Isn't aquaplas just latex paint?"
No not at all. It's now called AntiVibe but still made by the same company. It's been around for quite some time. The white coating on the 4310/4311/L100 woofers and the LE-14 is Aquaplas/Antivibe. Do a search and you will get plenty of industrial supply house links. It used to damp ductwork and many other sound related applications.
I have a sample and it's a heavy paste that flows under preasure. In most applications it gets sprayed on. You can see the silica fillers in it. When it dries it's a matte finish with a "sparkles".
Tried doing some home grown experiments with it before and after. I will take a look to see if I have the CSD plots. It was a real head scrather. Reminds me of the Enable thread. One of those I know it's doing something
I can hear it , now go and find what it is.Rob
My Uncle used to be authorized repair for Lansing. He says it was called Lansauplas (something like that) and it was latex paint with shredded paper mixed in. He made his own when they quite suppling it to him - maybe they changed the formula
Looking at the JBL/Harmon stock it looks like they are about to shut there doors - it was a trading at 120 a fw months ago and now is trading around 43.
Hopefully they'll pull through- although Radian does make some nice aftermarket diaphragms
Looking at the JBL/Harmon stock it looks like they are about to shut there doors - it was a trading at 120 a fw months ago and now is trading around 43.
Hopefully they'll pull through- although Radian does make some nice aftermarket diaphragms
An externally hosted image should be here but it was not working when we last tested it.
