Lots of discussion. The consensus seems that it can't be measured.
Anything can be measured, Its just knowing what you are looking for and how to accomplish the measurement.
ron
Anything can be measured, Its just knowing what you are looking for and how to accomplish the measurement.
ron
Hmmm. Seems like a big assumption that the cone initiates the wave at the center and therefore the wave doesn't hit the pattern until much later - noticeably to an ear that is. In any case, I'm no engineer but I find it hard to believe there is an AUDIBLE difference in the timing, and therefore that there would be an AUDIBLE effect on the timing of when the wave hits the pattern. Can someone point out some online references here?
Seems to argue against the first point. If there's a lag in the timing of the cone movement between the center and edge, then there MUST be a lateral movement of the EnABL pattern (given pivot points). If there's a lag, then there's a difference in when the center moves and when the edge moves, and therefore, when the edge moves there MUST be a lateral component of it's movement. If there is NO lag, then the first point is moot. Am I crazy or just totally misunderstanding all this? Again, any pointers would be appreciated.
Thanks,
Carl
I have proven in many cases that it can be measured. What do they call that animal that was made by a committee?ronc said:
😉
He would be surprised to find out there are lots more things involved in whatever he is satisfied with.😀 I certainly hope he is only temporarily satisfied.BudP said:
Yeah. I'm not thinking clearly tonight. That's my point. If the noise produced by speaker is above a certain level, then, for sure, some musical information is obscured which otherwise could be heard.
I'm slowly working my way through Pyschoacoustics, Facts and Models by Zwicker and Fastl and it's becoming clearer to me subjective experience can be correlated to measurements. I mean, I already knew that because of codecs - I'm getting a clearer idea of how.
BudP said:
G'day Bud,
My current EnABL configuration IS Fig. 2 and the results I am getting is what makes me excited about the potential for more improvement.
Fig.3 came from my (flawed) understanding of what I thought you were describing. Based on my listening so far I think fig.3 would not be as effective.
I was thinking the other day about dividing the baffle into 'perimeter zones'.
I have labelled them in order of greatest effect based on my listening & experimentation:
P.1 - Immediately around driver all four sides
P.2 - Immediately around the port all four sides
P.3 - This perimeter Would only require blocks on each side (top and bottom taken care of by P.1 & P.2)
P.4 - Haven't tried this yet, but I plan to use blocks on each side and across the top (bottom taken care of by P.1)
With regard to block size I have had great results with 6mm x 12mm AND 12mm x 24mm.
I was wondering whether to try the same block size all over or perhaps I could calculate the block size for each individual perimeter?
What are your thoughts??
Cheers,
Alex
PS - On a side note - I find the discussion around 'added mass' to the cone very interesting.
Science aside, I was very sceptical of EnABL but open minded enough to try it for myself.
I applied EnABL only to the baffle BEFORE I did anything to the drivers.
For me the improvement was so dramatic that EnABLing the cones was the obvious next step.
So far I have done my main speakers, small bookshelf speakers and most recently a pair of two way PA speakers - which now sound incredible!
Physics, measurements, science - they all play their part, but it seems to me that people who scoff at EnABL have not properly applied it to 'paper' cones, baffles or not at all!!
My challenge to the detractors is to try EnABL on their baffle only, then listen for themselves.
Want a reversable and effective way to try EnABL?
See here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=116773&highlight=
Attachments
The measurement thing is pretty simple to explain. First of all, even a relatively cheap mic has greater sensitivity than our ears. Thus when you stick a mic in a sound field the electrical signal from the mic contains all the information in the sound field that the ear receives. As Ron said, it's just a matter of knowing what to look for in the data.
One thing the analysis of the added mass effect tells us is that we should expect differences in frequency response. When we look at enabled drivers we find that to be true. We observe a change in the FR, for better or worse. The analysis tells use where to look and what to look for. It's an aid to deciphering the data. That is why long ago I said the problem is not what enable does, understanding the possibilities of what it can do is what matters. Analysis can show us the way. Through analysis we can ask the “what if” questions about how the treatment might work. Through analysis we can consider the role of, for example, a BL or modified by the pattern. We can look at what happens when we ignore BL effects and compare them to what happens if we include them. By comparing the results of this type of analysis we can make a conclusion about the significance of BL effect on the real result. In the real world BLs are always present if the physics is such that they should be present. Thus from our analysis of the role of the BL we then know whether or how it might alter the result. Form my analysis, which is considerably deeper than what I have posted for discussion, the conclusion I reach is that whatever the effect of the enable patches, the roll of any BLs can only reduce their effectiveness. The roll of the Bl itself appears to be inconsequential.
One other point I would like to make is the simple observation that if an enable patch were so disruptive to any BL and the effect were consequential, then we must ask, wouldn't the surround bulge pose a bigger disruption? The answer is of course yes. After all, the surround is like a speed bump and the enable patches like a few pebbles on the road in front of it.
One thing the analysis of the added mass effect tells us is that we should expect differences in frequency response. When we look at enabled drivers we find that to be true. We observe a change in the FR, for better or worse. The analysis tells use where to look and what to look for. It's an aid to deciphering the data. That is why long ago I said the problem is not what enable does, understanding the possibilities of what it can do is what matters. Analysis can show us the way. Through analysis we can ask the “what if” questions about how the treatment might work. Through analysis we can consider the role of, for example, a BL or modified by the pattern. We can look at what happens when we ignore BL effects and compare them to what happens if we include them. By comparing the results of this type of analysis we can make a conclusion about the significance of BL effect on the real result. In the real world BLs are always present if the physics is such that they should be present. Thus from our analysis of the role of the BL we then know whether or how it might alter the result. Form my analysis, which is considerably deeper than what I have posted for discussion, the conclusion I reach is that whatever the effect of the enable patches, the roll of any BLs can only reduce their effectiveness. The roll of the Bl itself appears to be inconsequential.
One other point I would like to make is the simple observation that if an enable patch were so disruptive to any BL and the effect were consequential, then we must ask, wouldn't the surround bulge pose a bigger disruption? The answer is of course yes. After all, the surround is like a speed bump and the enable patches like a few pebbles on the road in front of it.
Thanks for the contributions, john.
So I would be correct in saying, would I not, that if Bl contribution is inconsequential, then on a baffle that is generally not moving and the EnABL patches not contributing to any significant added mass nor damping of the baffle, that it is logical to conclude that it has relatively inconsequential effects on diffraction, other than as "a few pebbles"? In fact, it would therefore be contributing TO the diffraction, since it is a discontinuity of the flat baffle area, were it significant in mass, therefore height above the baffle.
Dave
john k... said:
So I would be correct in saying, would I not, that if Bl contribution is inconsequential, then on a baffle that is generally not moving and the EnABL patches not contributing to any significant added mass nor damping of the baffle, that it is logical to conclude that it has relatively inconsequential effects on diffraction, other than as "a few pebbles"? In fact, it would therefore be contributing TO the diffraction, since it is a discontinuity of the flat baffle area, were it significant in mass, therefore height above the baffle.
Dave
Re: Thanks for the contributions, john.
I think that is reasonable. And if the BL did anything then I would expect the effect of the pebble induced diffraction to be reduced by it. As far as energy transferred to the baffle, the angle of incidence of the acoustic wave traveling over the baffle should be very shallow, likely in excess of the critical angle, and therefore little or no acoustic energy should transmitted into the baffle. Any acoustic energy radiated by the baffle would predominantly arise from mechanical energy transferred to the baffle through the mounting of the driver to it.
If you want to take it a step further then we must recognize that any acoustic BL which would be present would be present over the entire baffle surface. Thus any incident wave, reflection or diffraction, regardless of the source (enable patch or baffle edge), which propagates over the baffle would encounter this BL, whatever its effects. Additionally, any restructuring of such a BL due to the presents of an enable patch would necessarily be limited to a very small region of the baffle in the very immediate area of the patch. So any wave propagating over the baffle would encounter a BL which was no different from that of an untreated baffle over the vast majority of the baffle surface.
dlr said:
I think that is reasonable. And if the BL did anything then I would expect the effect of the pebble induced diffraction to be reduced by it. As far as energy transferred to the baffle, the angle of incidence of the acoustic wave traveling over the baffle should be very shallow, likely in excess of the critical angle, and therefore little or no acoustic energy should transmitted into the baffle. Any acoustic energy radiated by the baffle would predominantly arise from mechanical energy transferred to the baffle through the mounting of the driver to it.
If you want to take it a step further then we must recognize that any acoustic BL which would be present would be present over the entire baffle surface. Thus any incident wave, reflection or diffraction, regardless of the source (enable patch or baffle edge), which propagates over the baffle would encounter this BL, whatever its effects. Additionally, any restructuring of such a BL due to the presents of an enable patch would necessarily be limited to a very small region of the baffle in the very immediate area of the patch. So any wave propagating over the baffle would encounter a BL which was no different from that of an untreated baffle over the vast majority of the baffle surface.
more BL
John K. continues to do yeoman's work explaining the reality vs. fiction on this subject. Great job, very much appreciated.
Slightly off topic, boundary layers can have enormous impact on other processes. Ever wonder how all that chrome on car bumpers and motorcycles gets so shiney? It's not just from buffing (which is also a boundary layer influenced phenomena) but is due to BL kinetrics in the plating solutions. Turns out, if certain organic chemicals are added to nickel and copper plating solutions, they act as insulators over microscopic peaks on rough surfaces, as they are preferentially adsorbed onto the surface compared to the copper or nickel ions in solution. The amount of adsorption (and hence insulation/blocking) of the metal ions is governed by Ficks 2nd law of diffusion, Reynolds #, etc. through the BL necessarily existing between the solution and the surface being plated. The metal ions are forced to deposit into microscopic valleys as opposed to the peaks projecting out where the BL is thinner, because those peaks are preferentially covered with the insulating film (saccharine works well in nickel plating, believe it or not).
So, lest one think BL theory only applies to airflow over surfaces, it also applies in alot of other fields. It's imperative to understand when the concept has value, and when it's effects are neglible.
Thanks again John K. for thoroughly debunking BL theory applied to sound reproduction effects of EnABL.
John L.
John K. continues to do yeoman's work explaining the reality vs. fiction on this subject. Great job, very much appreciated.
Slightly off topic, boundary layers can have enormous impact on other processes. Ever wonder how all that chrome on car bumpers and motorcycles gets so shiney? It's not just from buffing (which is also a boundary layer influenced phenomena) but is due to BL kinetrics in the plating solutions. Turns out, if certain organic chemicals are added to nickel and copper plating solutions, they act as insulators over microscopic peaks on rough surfaces, as they are preferentially adsorbed onto the surface compared to the copper or nickel ions in solution. The amount of adsorption (and hence insulation/blocking) of the metal ions is governed by Ficks 2nd law of diffusion, Reynolds #, etc. through the BL necessarily existing between the solution and the surface being plated. The metal ions are forced to deposit into microscopic valleys as opposed to the peaks projecting out where the BL is thinner, because those peaks are preferentially covered with the insulating film (saccharine works well in nickel plating, believe it or not).
So, lest one think BL theory only applies to airflow over surfaces, it also applies in alot of other fields. It's imperative to understand when the concept has value, and when it's effects are neglible.
Thanks again John K. for thoroughly debunking BL theory applied to sound reproduction effects of EnABL.
John L.
Re: more BL
So the process must now be called EnA and await the final letters?
auplater said:
So the process must now be called EnA and await the final letters?
Re: Re: more BL
😀 Good one!
Out of interest, what are the temporary enclosures you are using?
Have you EnABL'd the baffle?
Cheers,
Alex
Alan Hope said:
😀 Good one!
Out of interest, what are the temporary enclosures you are using?
Have you EnABL'd the baffle?
Cheers,
Alex
>>> I applied EnABL only to the baffle...
Alex, you are cracking me up with the baffle treatment - LOL!
Alex, you are cracking me up with the baffle treatment - LOL!
That is the understanding I have, but the EnABL pattern is not applied to the entire surface. The only material that is applied to the entire surface is a coating of acrylic, and the intent of this coating is to allow that incident wave, to attach to the boundary layer, the acrylic is intended to facilitate. The pattern is applied to reduce/remove the possibility, of incipient standing wave reflected energy, from reflecting, while attached to the boundary layer. Whatever portion of the diffraction that would be caused by this uncontrolled reflection is forced to emit from the edge of the surface, just beyond where the EnABL pattern exists.
The lack of a "flow" of air is immaterial. There is most definitely a "flow", but it is not of molecular material, all that is flowing is the energy that is compressing air molecules together, as it passes through them. Longitudinal compression waves, out in the room, are not a "flow" of molecules either. Energy passes through the air, compressing molecules together, but the molecules do not move a significant distance, as the energy passes through them.
I am not certain about the angle of incidence argument either. An expanding energy wave must apply a lateral force pretty close the force of it's direction of movement, or it is difficult to see how it can expand in a spherical fashion, in a 4 pi environment. The same energy that allows that expansion, with it's losses, is available in a 2 pi environment. Does this not indicate significantly greater energy, available in a lateral direction, as the energy wave crosses a surface that is creating a 2 pi environment?
The boundary layer I am postulating is not comprised of flow across a surface. Energy transform from one medium to another, regardless of disparities in medium, must have a boundary layer, or if that is not a useful term, then a zone of transformation. I am arguing that there is a special case of boundary layer event, where energy transform is across a still boundary layer.
With this statement, John K has confirmed that gross piston movement compression, is not the description of an emitting diaphragm, except at one and perhaps three distinct frequencies.
If we are to throw out the possibility of a boundary layer, even one being enhanced by the specific EnABL patterns and specific conformal coating material, then here is the situation we are left with.
The voice coil moves, a shear wave is introduced into the cone and it begins to move through the cone material, displacing the mesh of elastically bound masses a few microns. According to dlr and Beraneck the speed of this movement is, in Dave's portrayal, considerably faster than the speed through air of the longitudinal wave, also initiated when the shear wave was introduced to the cone. Beraneck thought this speed differential was dependent upon frequency.
So, we have a situation where the initial compression wave is added to and subtracted from by a continuous compression wave, created by a transverse wave moving through the cone, faster than the initial compression wave moves through adjacent air. This provides us with a combined compression wave that is perhaps generally flat, as it passes from the tip of the suspension medium, but is internally pretty chaotic. Plus, there are reflected transverse waves, ringing within the cone and adding their resultant constructive and destructive compression waves to the general chaos of this exiting compression wave, before it is able to move beyond the suspension tip.
This would indicate poor information intelligibility, until these minor compression waves have dissipated and/or become somewhat more coherent to the initial, hemispherical compression wave. This also suggests a mixing zone, out away from the speaker, beyond which the sound becomes noticeably more understandable, both on and off axis. In addition a "beaming" of enriched information, from the initial hemispherical compression wave should persist.
This describes most untreated drivers pretty well. Lots of after the fact activities are applied, to reconfigure this situation.
Properly EnABL'd drivers do not exhibit these subjectively understood characteristics. It remains to be seen what remains of them in objective tests
Subjectively, the EnABL driver mix zone is within an inch or two and often quite a bit less, of the driver surface. Enriched beaming, on axis, does not exist. Subjective frequency response, off axis, is much smoother and more even and in some cases does not audibly change across the included arc of the diaphragm.
If there is not an enhanced boundary layer event, within which the EnABL mechanism is working, are we to assume that EnABL is functioning out, off of the cone surface? Some sort of remote manipulation? Or, perhaps we are to assume that the patterns instruct the transverse wave, below them in the cone, to not interfere with the expanding compression wave, that knows nothing about these edge conditions? Should we assume that a mass as slight and as localized as this, informs the movement of all of the masses within the mesh?.
Without a boundary layer, the alternative mechanisms I can conceive of, for EnABL's influence, become pretty absurd. And we do now have proof that there is a very noticeable effect, on the measured compression wave, out away from the chaotic events on the cone. Again, thank you John K.
As another, likely unappreciated anecdotal bit, Lynn Olson and others were presented with a blind test at the recent RMAS, in the Lowther America / Nelson Pass listening room. Lynn is as good a subjective / objective investigator as anyone posting on this thread. You only have to hear, or measure, his Ariel speaker system to realize this.
No one in the room knew which Lowther driver was EnABL'd. The pattern had been applied with a translucent material, that, if you did not know exactly howt and where to look for it, you would not have noticed it.
Lynn was pretty critical of the sonic qualities of the set up in general. He heard many things that he knew of as particular problems, of particular components in the system. He had no idea which driver was EnABL'd either.
He noticed a difference that he characterized as a 20 dB drop in distortion and "clutter". From a system that irritated him significantly. He reported which listening portion showed this characteristic and all others who have posted, also chose this session, as providing a very noticeably superior sound quality.
Clarity of detail information coherency and loss of distortion was reported separately by a number of attendees. John Ver Halen did not disclose which session utilized the EnABL'd Lowther, until a few days later.
I don't see a 20 db change in any test data to date. I am not looking for one either. EnABL works in the area of intelligibility. We have found it's light footprints in FR, CSD possibly phase and to a small degree, in THD and it's components, including a pretty dramatic looking, very narrow spike that includes only odd harmonics. I do think that this subjective area of intelligibility, trumps all of the objective tests of our current test equipment. I am sure we will find this intelligibility recorded in these tests, but not it's disproportionate importance.
The mechanism I detailed earlier, for a non boundary layer influenced driver, does agree with the subjective experience from untreated drivers. What other mechanism are we going to postulate, for an EnABL'd driver, that agrees with the subjective experience, other than a boundary layer function?
Bud
EnAB**
I disagree with your attempted conclusions, Bud, but don't disagree that EnAB** has some perceived effect.
I believe the effect is in the psychoacoustic realm of space-time-perception continuum, and, as such, does not involve a physical component resultant expressed from the well known acoustic propagation properties of evaluated system/driver combinatorial exercises.
Hence the never ending search for a physical reality that most likely does not exist.
Subjective... for sure 😉
Objective... nope
John L.
I disagree with your attempted conclusions, Bud, but don't disagree that EnAB** has some perceived effect.
I believe the effect is in the psychoacoustic realm of space-time-perception continuum, and, as such, does not involve a physical component resultant expressed from the well known acoustic propagation properties of evaluated system/driver combinatorial exercises.
Hence the never ending search for a physical reality that most likely does not exist.
Subjective... for sure 😉
Objective... nope
John L.
Re: Re: Re: more BL
Um ... cheap Woolworths breadbins. To let me break in the Fostexes over the winter.
Alans EnABL Album
Will be making & installing phase plugs next tuesday (friend with a lathe). These will be EnABL'd. No I've not done the baffle - but just might do the Sachikos. Can't see what I have to lose, and I'm planning to cover the drivers anyway.
And - Auplater - I suspect from your post that you have never actually listened to an EnABL'd driver. You should try it some day. 🙂
Alex from Oz said:
Um ... cheap Woolworths breadbins. To let me break in the Fostexes over the winter.
Alans EnABL Album
Will be making & installing phase plugs next tuesday (friend with a lathe). These will be EnABL'd. No I've not done the baffle - but just might do the Sachikos. Can't see what I have to lose, and I'm planning to cover the drivers anyway.
And - Auplater - I suspect from your post that you have never actually listened to an EnABL'd driver. You should try it some day. 🙂
Re: EnAB**
How can this 'psychoacoustic effect' apply under 'blind test' conditions?
You may well be right that 'well known' acoustic science cannot express EnABL's resultant effect. That in itself is not sufficient to support your own conclusion.
At one time it was 'well known' that the earth is flat and at the center of the solar system...
Alan,
Those breadbins look surprisingly good in your photos. Go on EnABL them I dare you!
Godzilla,
Yeah, I'm a bit obssessed with baffle EnABL, but the difference between a disABL'd baffle vs. EnABL'd is amazing
😀 😀
How can this 'psychoacoustic effect' apply under 'blind test' conditions?
You may well be right that 'well known' acoustic science cannot express EnABL's resultant effect. That in itself is not sufficient to support your own conclusion.
At one time it was 'well known' that the earth is flat and at the center of the solar system...
Alan,
Those breadbins look surprisingly good in your photos. Go on EnABL them I dare you!
Godzilla,
Yeah, I'm a bit obssessed with baffle EnABL, but the difference between a disABL'd baffle vs. EnABL'd is amazing
😀 😀
This may be the intent, but there's no evidence whatsoever that this actually occurs. You'd have to use something such as a laser interferometer to show the change in diaphragm output. It's nothing more than conjecture at this point, contrary to the physics so clearly described by john.
BudP said:
How would you have any idea as to the point of origin of what you think you are hearing? An inch or two off of the surface? You're EARS tell you the distance so precisely? Jeez, Bud, where does this stuff come from? Do you want to have any credibility remaining?
What?????
Since all drivers (save possibly those of Geddes and he's still working on them) are without question directional and NOT constant directivity, I can only conclude from this statement that you are not able to detect the changes in the off-axis. This is where a full, valid set of on- and off-axis measurements are a requirement. If the driver responds as you say, there will be absolutely NO difference in the measured responses. If there is any at all, it's direct evidence contradictory to your claim here. This is all making the assumption that it could be the case.
No to all. It's primarily an effect of distributed added mass and damping, with possibly a small, insignificant amount of diffraction added into the mix and maybe some localized stiffening of the diaphragm. The only evidence seen is a shifting of resonances, some damping of some of them and introduction of new ones. All to be expected.
And to be fully accurate, no one can make any conclusions as to the effect since it's been shown that there are frequency response changes and these FR changes are known to change perception of a driver. The impact of this couldn't be separated from any other supposed effect in that sort of test scenario, possibly not in any.
I find it more than curious that there are proven alteration in FR that you think are not significant, yet you concentrate on distortion or other "mechanisms" that are 20db down or more in level. This can't be reconciled in any acceptable way. The large changes aren't noticed, the tiny ones are. What's wrong with this picture?
And in following the thread in which Olson is involved, I have little confidence in his descriptions. That is to say, I can't say that I'd trust his ears. Actually, I'll state that I explicitly don't trust them.
All I can say is, so what? One would have to believe him capable of being precise and actually able. I don't believe it for a moment. That would have to be taken on faith, it's not a reputable way to work and certainly no proof, it's just a diversion. Citing other subjectivists on what they think they hear is not useful except to believers.
In your mind it agrees. Simply saying so does not make it so. There's no evidence other than hearsay.
My conclusion based on the facts, the reputable evidence and the theory is that there's nothing special going on, just what one would expect form frequency response alterations. I suppose I should try to say that my treatment of the surround is making the same change. However, if so, then the enabl patent would be invalid due to prior art, since manufacturers have applied that and other surface treatments to drivers long before the enabl patent. The one and only part of the patent that might stand would be the pattern.
New attempts to describe (or question) the physics based on ears will work with believers, but it is it is nothing more than trying to find a way around the actual physics john presented and the factual evidence.
Dave
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