Graham Maynard said:
As spind suggested, this is the problem. There is no basis on which to believe it is audible. Nothing to date suggests that it can be. It's hearing what one wants to hear, then trying to justify it.
You disagree because you refuse to accept the fact that there is no evidence to support your position other than a belief with anecdotes even though all factual data presented are in complete contradiction to your assumptions and belief.
Belief: "a vague idea in which some confidence is placed", although it seems to be complete confidence.
Dave
Graham Maynard said:
Hi,
"audible even in the slightest degree" is completely unprovable.
Thankfully it is currently not the issue. The issue is, is it measurable.
If it is not then end of story. If it is then argue freely about audibility.
There is nothing that currently suggests it will be measurable.
🙂/sreten.
OK guys, help me out here. Re: baffle edge diffraction, I keep hearing that EnABL can't have an effect b/c it's before the edge. But...
The bending of the waves at the edge would seem to create a changed pressure gradient, and that change seems like it COULD have an impact BEFORE the edge. (Wave diffraction along a shoreline certainly seems to have an effect before the bend in the shoreline).
Now I'm not saying John K or Dave or anyone else is wrong about the effects of EnABL (why would I subject myself to such merciless barrages
), and I'm certainly not saying it would be audible. But for theory's sake, I have to wonder if it's actually true that diffraction can't be impacted by anything on the baffle BEFORE the edge. Doesn't make intuitive sense to me.
Carl
The bending of the waves at the edge would seem to create a changed pressure gradient, and that change seems like it COULD have an impact BEFORE the edge. (Wave diffraction along a shoreline certainly seems to have an effect before the bend in the shoreline).
Now I'm not saying John K or Dave or anyone else is wrong about the effects of EnABL (why would I subject myself to such merciless barrages
), and I'm certainly not saying it would be audible. But for theory's sake, I have to wonder if it's actually true that diffraction can't be impacted by anything on the baffle BEFORE the edge. Doesn't make intuitive sense to me.Carl
Graham,
Sorry if your post means you'll stop contributing. This thread is dominated by 3 or 4 parties who are firm in their beliefs and conclusions (right or wrong), and as much as they like to chide "believers" for their dogged determination, at least the "believers" are mostly civil in how they doggedly present their cases.
I must say publicly at this point that the tone of the challengers belies some clear lack of confidence. They remind me of the playground bully. I'm hopeful that this post passes muster of the moderators as it's tone is certainly no more critical or harsh than other posts that are allowed to remain...
Carl
Sorry if your post means you'll stop contributing. This thread is dominated by 3 or 4 parties who are firm in their beliefs and conclusions (right or wrong), and as much as they like to chide "believers" for their dogged determination, at least the "believers" are mostly civil in how they doggedly present their cases.
I must say publicly at this point that the tone of the challengers belies some clear lack of confidence. They remind me of the playground bully. I'm hopeful that this post passes muster of the moderators as it's tone is certainly no more critical or harsh than other posts that are allowed to remain...
Carl
...and are doggedly determined not to subject themselves to listening to a set of "properly" treated speakers...hmmm?
Carlp said:OK guys, help me out here. Re: baffle edge diffraction, I keep hearing that EnABL can't have an effect b/c it's before the edge. But...
The bending of the waves at the edge would seem to create a changed pressure gradient, and that change seems like it COULD have an impact BEFORE the edge. (Wave diffraction along a shoreline certainly seems to have an effect before the bend in the shoreline).
Now I'm not saying John K or Dave or anyone else is wrong about the effects of EnABL (why would I subject myself to such merciless barrages
Carl
No one has said that the wave cannot be altered prior to reaching the edge. John's measurements show that the Mortite ring does indeed alter the signal, but it is much larger in impact than enabl. Even so, it's still almost insignificant in its alteration of the wave. Therefore the edge diffraction will also be altered in an almost insignificant way. As John said, it's like driving over a pebble just before you driver over a cliff.
The point about the diffraction John points out is that on a smooth baffle, there is no diffraction, that is, the wave is not altered, until it reaches the edge. If it reaches the edge unaltered or insignificantly so, then the diffraction created when it reaches the edge will be unchanged.
There are effective ways to improve (rather than simply alter) the diffraction and that does involve something on the baffle prior to the edge. This is a damping material such as felt or acoustic foam. In fact, it has to be used prior to the edge. Placed on the side just past the edge and there is little, if any improvement. I've tried this in a number of ways to no avail. However, felt on the baffle is very effective (though not 100@).
A roundover of the edge is the only other effective way to ameliorate diffraction. It can be thought of as being before the edge if the side of the box is defined as the baffle edge. The effectiveness is dependent upon the radius and the box shape itself (round, rectangular, etc.). 3/4" is about the smallest of any usable effectiveness.
The point is that the extremely small dimensions of enabl are insignificant in controlling the edge diffraction because it does not and cannot alter the wave in any significant amount. John shows not only the math behind the possibility, but also the proof in the measurements.
Dave
Carlp said:
Really, bullys? Since when is clamoring for scientific proof "bullying?" This thread has been full of pseudoscientific :bs:
Listen. It's fine to talk about cables and vinyl, bybee filters, and EnABL. If you perceive a difference, and you've got the time and money-no one will stand in your way. I prefer silver face over black equipment. I feel it sounds better...
However, horking up a big ol' hunk of pseudoscientific bezoar and claiming this scientifically validates EnABL, well...
Is it harsh to ask for scientifically accepted proof?
-There is no clear scientific rationale for EnABL.
-There is no objective study evidence that anyone can hear a difference.
-What objective evidence we have, i.e. John's experiments, tends to support the lack of any effect.
The proponents of EnaABL have not met any accepted scientific burden of proof.
Ed LaFontaine said:
Who's talking about speakers at this point? We're speaking of baffles at this time. How often must you and others be reminded so that you will stop making this bogus claim? From day one no one has said that a driver will not be altered. Period. It will, as any driver will when mass is added.
I have from day one and will continue to point out that there will not be a significant change made by enabl on a stationary surface. John's measurements are the proof. You are entitle to continue to deny the evidence, but please stop making false charges.
I would also ask, what can one do when hard data is denied with nothing but belief as the basis? There' s been no evidence of any sort to the contrary. That is what it is, like it or not.
Dave
UCLA88,
Did I say "clamoring for scientific proof" was "bullying?" I think not. I simply said the tone, which I see as patronizing at best, makes some sound like they are making up for a lack of confidence. If all I heard was a calm and rational call for scientific proof, I'd keep my keyboard shut.
I am trained as a scientist (biologist/ecologist) so I don't begrudge anyone calling for scientific proof. But true scientists are dispassionate in their scientific pursuits. I don't see any of that here. I hear a lot of people passionately attacking anyone who tries to consider all possible angles related to EnABL. It would seem to me to make scientific sense to look at all angles - be sure you've considered all possibilities before making sweeping statements about the psychological leanings of other members.
Why would we, DIY'ers all, treat each other as if we were mortal enemies? Frankly, I've never understood the battles over cables or different kinds of sand (tubes vs silicon) or vinyl vs plastic, etc etc. I have my own biases as you do, but I would never say someone else doesn't actually hear something that I don't - even if I believe after some experimentation that copper wire is largely copper wire. I see no reason to get bent out of shape over who's got the biggest...er...best evidence for their case.
Back to this thread, maybe the EnABL afficionados aren't scientists, but aside from occasional science presented by a few, I don't see ANY scientists here.
Carl
Did I say "clamoring for scientific proof" was "bullying?" I think not. I simply said the tone, which I see as patronizing at best, makes some sound like they are making up for a lack of confidence. If all I heard was a calm and rational call for scientific proof, I'd keep my keyboard shut.
I am trained as a scientist (biologist/ecologist) so I don't begrudge anyone calling for scientific proof. But true scientists are dispassionate in their scientific pursuits. I don't see any of that here. I hear a lot of people passionately attacking anyone who tries to consider all possible angles related to EnABL. It would seem to me to make scientific sense to look at all angles - be sure you've considered all possibilities before making sweeping statements about the psychological leanings of other members.
Why would we, DIY'ers all, treat each other as if we were mortal enemies? Frankly, I've never understood the battles over cables or different kinds of sand (tubes vs silicon) or vinyl vs plastic, etc etc. I have my own biases as you do, but I would never say someone else doesn't actually hear something that I don't - even if I believe after some experimentation that copper wire is largely copper wire. I see no reason to get bent out of shape over who's got the biggest...er...best evidence for their case.
Back to this thread, maybe the EnABL afficionados aren't scientists, but aside from occasional science presented by a few, I don't see ANY scientists here.
Carl
So we should give up on looking at this? So there is proof that there is no effect? Lack of proof isn't proof of lack - remember basic statistics?
John K has presented some fairly compelling theory and evidence re: baffles and diffraction, and beyond that I don't have the chops to know if there could be other things not yet considered (re: baffle effects). Others do seem to think so, and I, as a curious human, am always interested in exploring possibilities. Roll over if you want, that's your prerogative.
Carl (OK, my dander is up. Sorry, got to take a dose of my own medicine...😀 )
Carlp said:
Bud and others wrote a lot of words about the desire for someone to provide measurements. When it proved to be in total contradiction, there was denial and simply more requests for "other" measurements to find out what was "really" going on. Denial is the real issue.
As for me, I find no need to consider something that through many years (in the neighborhood of ten) of tests, measurements and listening experience I know to have no possibility of significant effect. Consider the reaction from Bud when John did exactly that. "Thanks, now let's get on with finding out what's really going on.".
You tell me how one should treat this essential denial?
Dave
Ed LaFontaine said:
Given the backgrounds of the "naysayers", would it not be normal?
I don't think it's a valid arguement to think that there is underlying intent to discredit anything.
None of the "naysayers" are saying that there couldn't be differences heard with an EnABL treatment on the cone of a driver. It's a very well known fact that mass changes the performance of a driver.
I have spoken to one driver manufacturer who has experimented with different glues at the junction of the cone to the surround and found that there were differences in measures responses that would be well outside the bounds of simple manufacturing tolerance differences in drivers.
JohnK goes to the effort to back his positions with diagrams, explanations that are based on hard science. He's not merely postulating.
Does EnABL affect the performance of a driver?
Why wouldn't it?
Is it a universal technological improvement to all drivers?
Probably not.
Even if hypothetically it was, I think that the size of blocks, spacing, diameter of EnABL patterns would have to be developed based on trial and error tests for each and every different driver that it was applied to, regardless of diameter.
If EnABL was a boundary layer effect, or laminar flow effect. It could very easily be modelled with a homemade windtunnel rig and strain gauges. There are many tests one could perform for lift and drag at numerous angles of incidence. Smoke tests could be done to visually illustrate boundary layer effects.
Why aren't the proponents of EnABL doing these to try and uncover the origins of the "audible" effects of EnABL?
Jess playin' devil's advocate.... 😀
Cheers
OK, last one for a while, I promise.
OK, Dave, this post is helpful. I sense there is still disagreement by some that the EnABL pattern amounts to, essentially, a smooth baffle, but John K has made a strong case for that. I don't have a clue but still want to listen to the debate. And...I still may try it for myself (if I can ever find the time, what with all these important thread replies I have to post 🙄 ).
Carl
Edit - Dave, just saw your response. My suggestion is that after a polite response with whatever you feel is adequate evidence, ignore it. BTW, I hear Bud simply asking for someone to measure what he (and many others) seem to be quite certain they hear. Reasonable request if you're in their shoes. If ya don't want to help him, let it be.
OK, Dave, this post is helpful. I sense there is still disagreement by some that the EnABL pattern amounts to, essentially, a smooth baffle, but John K has made a strong case for that. I don't have a clue but still want to listen to the debate. And...I still may try it for myself (if I can ever find the time, what with all these important thread replies I have to post 🙄 ).
Carl
Edit - Dave, just saw your response. My suggestion is that after a polite response with whatever you feel is adequate evidence, ignore it. BTW, I hear Bud simply asking for someone to measure what he (and many others) seem to be quite certain they hear. Reasonable request if you're in their shoes. If ya don't want to help him, let it be.
Carlp said:
When claims begin to border on the preposterous, I think that anyone's dispassion will get pushed to the limits.
This, then becomes a diversion.
Cheers
Well said, Carl.
I don't know of any scientific reason why enabling might, (note, might) or might not work. But then what do I know?
Unfortunately this thread produces a lot of heat but no light.
My sympathies are somewhat with dlr and the Johns, its difficult to prove a negative, and sometime the babble definitely does not make sense. But until someone does a proper scientific listening test, with humans, not hardware, the suspicion will remain that there is something in it.
By the way, I'm an electronic (degree) engineer, so naturally sceptical, but I've seen too many things "scientifically" but wrongly "proved or otherwise" to discard lightly opinions from a significant group of lay people. On the other hand, one good scientific study, properly tested by peer review, can change the world. As yet, we have not had this from either side.
I don't know of any scientific reason why enabling might, (note, might) or might not work. But then what do I know?
Unfortunately this thread produces a lot of heat but no light.
My sympathies are somewhat with dlr and the Johns, its difficult to prove a negative, and sometime the babble definitely does not make sense. But until someone does a proper scientific listening test, with humans, not hardware, the suspicion will remain that there is something in it.
By the way, I'm an electronic (degree) engineer, so naturally sceptical, but I've seen too many things "scientifically" but wrongly "proved or otherwise" to discard lightly opinions from a significant group of lay people. On the other hand, one good scientific study, properly tested by peer review, can change the world. As yet, we have not had this from either side.
Hi Carl,
Re your Post#423 pressure gradient comment: I would add - or *baffle* radiation with edge diffraction components having been modified due to an EnABL pattern being close to the edge which is generating the diffraction.
The turning point for me was John's 'No' answer.
I cannot do the maths necessary to determine the effect of an induced localised coincidental pressure change acting upon on-going output at other frequencies. Air pressure does not affect wave propagation due to molecular density being directly inter-related, but when localised pressures (high) are induced by coincidental transverse wave motion (non-pistonic) due to contour change and at the centre of a cone without high frequency air flow allowing pistonic pressure equalisation, and boundary layer relationships for fractional flow are affected both by pressure and surface topology ???
So yes, I am out.
That is until someone provides a witnessable (say via youtube or freesound) demonstration of EnABL having an effect at a baffle edge or in a pipe, which no amount of technical posturing can refute, and whether that effect has been measured or not !
Cheers ........... Graham.
Re your Post#423 pressure gradient comment: I would add - or *baffle* radiation with edge diffraction components having been modified due to an EnABL pattern being close to the edge which is generating the diffraction.
The turning point for me was John's 'No' answer.
I cannot do the maths necessary to determine the effect of an induced localised coincidental pressure change acting upon on-going output at other frequencies. Air pressure does not affect wave propagation due to molecular density being directly inter-related, but when localised pressures (high) are induced by coincidental transverse wave motion (non-pistonic) due to contour change and at the centre of a cone without high frequency air flow allowing pistonic pressure equalisation, and boundary layer relationships for fractional flow are affected both by pressure and surface topology ???
So yes, I am out.
That is until someone provides a witnessable (say via youtube or freesound) demonstration of EnABL having an effect at a baffle edge or in a pipe, which no amount of technical posturing can refute, and whether that effect has been measured or not !
Cheers ........... Graham.
There is a lot of misunderstanding here on the baffle issue. Let me spell my position out. I think John's tests show exactly what he stated, no difference due to an EnABL equivalent "patch or single bar. I stated that right after he presented his original test.
As for my personal experiences, they are not on a round baffle and are not from test signals. And, I am not saying here that test signals are an inferior way to discover diffraction at a baffle edge, quite the contrary. However, in my personal set of speakers, with music as the only test source, there is not a detectable lobing, as you move across the speaker and then box that and move past the edge.
Anyone in the Seattle area that would like to come by and witness this is welcome to do so. I am not attempting to mislead anyone or misdirect this investigation. I have at all times spoken about what I find, irrespective of what I thought was causing what I found.
For those of you who have a truly skeptical position please look at two posts.
http://www.diyaudio.com/forums/showthread.php?postid=1461231#post1461231
http://www.diyaudio.com/forums/showthread.php?postid=1231568#post1231568
The first is a mouse over blink comparison between a treated and untreated 6 1/2 inch aluminum driver, with some particularly nasty standing wave problems. The test was part of a series provided by John K. Please note the ordering of the decay steps, removal of one node and general "tightening up" of the speakers characteristics, from only an inner and outer set of rings of an EnABL pattern.
The second is Soongsc test of an aluminum driver with a particular ring placement. One that totally disperses this drivers major standing wave node.
Both of these tests show exactly what EnABL is capable of, on a metal driver.
I have also had occasion to duplicate Soongsc's pattern position, on the same make and model of driver. I left his "mid cone" ring set until last and spent quite a long time, for me, getting used to the sound of this driver without that mid ring, but otherwise fully treated.
I then duplicated his mid cone ring position with the typical paint and I now know what it sounds like to have reduced a standing wave node, with painted blocks, in the middle of an aluminum cone. The difference is quite pronounced and certainly worth further investigation on other drivers. This does call into question the logical extension of John's mid baffle test's, as far as transferring them to the vibrating surface is concerned.
Does not mean I think Johns test was in any way invalid. I accept it at face value. I have questions about it's logical extension to an edge, but they are not questions about that logical extension to the edge of the baffle John used.
I have test results in hand that directly contradict their logical extension to the cone surface, from Soongsc's tests. I have also confirmed that just the paint, applied to the cone, will provide a more than just noticeable difference in the drivers musical performance. I have not shown that the paint is as effective as toothpaste, for a complete dispersal, and am not claiming that it is, or will be found to be.
Dave, I do think you misunderstood my meaning when I said let's get on with testing. At that point I was ready to accept Johns tests for just want he had, up to that point in time portrayed them as. I still accept Johns tests for exactly what they are. And, I still appreciate them. The testing I was referring to was the much more interesting to me exploration of EnABL patterns as a deliberately distributed mass, used to control specific cone departures from linear behavior.
That's right Dave, I am accepting a distributed mass as the method EnABL uses, to cause it's effects. I want to thank both you and John for clearly demonstrating this. Not that my acceptance of this amounts to a hill of feces.
Since we are working with a well established mechanism as our only one, it should be very easy to model how a patterned distribution of mass, on a cone, alters that cone's behavior. John has already looked at some random distributions of mass and Soongsc has shown that particular placement of patterned mass distribution is useful. So, it should now just be a matter of time and ingenious use of John L's test progressions and John K's knowledge, to come to a description of how to use EnABL, in an engineering environment.
Bud
As for my personal experiences, they are not on a round baffle and are not from test signals. And, I am not saying here that test signals are an inferior way to discover diffraction at a baffle edge, quite the contrary. However, in my personal set of speakers, with music as the only test source, there is not a detectable lobing, as you move across the speaker and then box that and move past the edge.
Anyone in the Seattle area that would like to come by and witness this is welcome to do so. I am not attempting to mislead anyone or misdirect this investigation. I have at all times spoken about what I find, irrespective of what I thought was causing what I found.
For those of you who have a truly skeptical position please look at two posts.
http://www.diyaudio.com/forums/showthread.php?postid=1461231#post1461231
http://www.diyaudio.com/forums/showthread.php?postid=1231568#post1231568
The first is a mouse over blink comparison between a treated and untreated 6 1/2 inch aluminum driver, with some particularly nasty standing wave problems. The test was part of a series provided by John K. Please note the ordering of the decay steps, removal of one node and general "tightening up" of the speakers characteristics, from only an inner and outer set of rings of an EnABL pattern.
The second is Soongsc test of an aluminum driver with a particular ring placement. One that totally disperses this drivers major standing wave node.
Both of these tests show exactly what EnABL is capable of, on a metal driver.
I have also had occasion to duplicate Soongsc's pattern position, on the same make and model of driver. I left his "mid cone" ring set until last and spent quite a long time, for me, getting used to the sound of this driver without that mid ring, but otherwise fully treated.
I then duplicated his mid cone ring position with the typical paint and I now know what it sounds like to have reduced a standing wave node, with painted blocks, in the middle of an aluminum cone. The difference is quite pronounced and certainly worth further investigation on other drivers. This does call into question the logical extension of John's mid baffle test's, as far as transferring them to the vibrating surface is concerned.
Does not mean I think Johns test was in any way invalid. I accept it at face value. I have questions about it's logical extension to an edge, but they are not questions about that logical extension to the edge of the baffle John used.
I have test results in hand that directly contradict their logical extension to the cone surface, from Soongsc's tests. I have also confirmed that just the paint, applied to the cone, will provide a more than just noticeable difference in the drivers musical performance. I have not shown that the paint is as effective as toothpaste, for a complete dispersal, and am not claiming that it is, or will be found to be.
Dave, I do think you misunderstood my meaning when I said let's get on with testing. At that point I was ready to accept Johns tests for just want he had, up to that point in time portrayed them as. I still accept Johns tests for exactly what they are. And, I still appreciate them. The testing I was referring to was the much more interesting to me exploration of EnABL patterns as a deliberately distributed mass, used to control specific cone departures from linear behavior.
That's right Dave, I am accepting a distributed mass as the method EnABL uses, to cause it's effects. I want to thank both you and John for clearly demonstrating this. Not that my acceptance of this amounts to a hill of feces.
Since we are working with a well established mechanism as our only one, it should be very easy to model how a patterned distribution of mass, on a cone, alters that cone's behavior. John has already looked at some random distributions of mass and Soongsc has shown that particular placement of patterned mass distribution is useful. So, it should now just be a matter of time and ingenious use of John L's test progressions and John K's knowledge, to come to a description of how to use EnABL, in an engineering environment.
Bud
Carlp said:
The wave radiating outward form the driver is not affected by the edge until it gets there. At the efge it is diffracted which results in a secondary wave propogating out from the edge. The resultant pressure at any point is the obtaioned fromt he sum of these two waves. One wave does not affect the other. That is, they are both independently solutions othe wave equation as is their sum.
BudP said:
Could you perhaps provide a layout of you speaker front baffle? Where are they located and what size are the drivers. What size is the baffle. Is it a square edge or roundeded? If rounded, what radius? If a two or more way, what is the crossover point? How big are the enable patches, L, W, H?
Seattle! That explains it. You do realize that the moisture in the air and changes there of will sactter more sound than enable on a baffle? 🙂
Never been an argument there. But the tests I did do not show damping to be particularly altered. They show modified frequency response with shifted resonances that still decay in 3 to 4 msec.
I did the edge test Bud. Maybe you missed it. Same result.
I would strongly argue that. My tested showed the effect of the patch on an acoustic wave propagationg over it. The same will apply to an acoustic wave propogation over a moving surface. But lets 1) not confuse wave propagation over a surface with wave generation by the movement of the surface, and 2) I haven't seen any measurement of any driver that isolated a the effect of frequency response modification to one thing or the other. All we have is the end result combined with other observations which point to the root cause.
Yes, differences. Not necessarily improvements. And differences that could be obtained through any manner of alteration. Recall some of my driver mods were much more effective at smoothing the response of my test driver.
Your welcome.
Already been done but at this time not in the realm of DIY computing.
John K,
I absolutely agree, significantly better at smoothing the bulk frequency response. However, smoothing is not what I am after. What I am after is a large reduction in latency and an equally large reduction in threshold. The smoothness, actual bandwidth, distortion of sine signals, are all elements outside of what I am concerned with. Does not mean I think them unimportant either.
The latency is the rise time to full signal strength and the threshold is how far down in relative signal strength can the driver emit a signal coherently.
In musical instrument terms, and specifically in terms of a single piano note. How closely will the speaker track the rise time of the vibrating strings, after the hammer strike. and how far down the decay slope will those vibrations still be coherent
The work you have done has shown quite clearly that it is an organized mass loading, in very specific locations, that is the EnABL mechanism. What interests me currently is correlating those non random masses with changes in objective test measurements.
Soongsc has already journeyed down this path, and provided some very interesting CSD plots that show an unknown to me, full range driver, with a decay structure from an impulse test shown in a CSD plot, that is remarkably close to that of a ribbon tweeter. All he has been manipulating are the patterned mass loadings on the driver surface. Very small pattern artifacts at that.
Bud
I absolutely agree, significantly better at smoothing the bulk frequency response. However, smoothing is not what I am after. What I am after is a large reduction in latency and an equally large reduction in threshold. The smoothness, actual bandwidth, distortion of sine signals, are all elements outside of what I am concerned with. Does not mean I think them unimportant either.
The latency is the rise time to full signal strength and the threshold is how far down in relative signal strength can the driver emit a signal coherently.
In musical instrument terms, and specifically in terms of a single piano note. How closely will the speaker track the rise time of the vibrating strings, after the hammer strike. and how far down the decay slope will those vibrations still be coherent
The work you have done has shown quite clearly that it is an organized mass loading, in very specific locations, that is the EnABL mechanism. What interests me currently is correlating those non random masses with changes in objective test measurements.
Soongsc has already journeyed down this path, and provided some very interesting CSD plots that show an unknown to me, full range driver, with a decay structure from an impulse test shown in a CSD plot, that is remarkably close to that of a ribbon tweeter. All he has been manipulating are the patterned mass loadings on the driver surface. Very small pattern artifacts at that.
Bud