Carlp said:
Here, here. And since we can't speculate on whether or not there is even anything to measure, and theory says virtually nothing will happen, and data we've seen so far says almost nothing happens, this thread will now be closed for lack of anything to talk about...
Carl
No skeptic of the mechanism, not one, has ever said nothing will happen. You're being disingenuous. But your suggestion of what to do is actually closer to the truth than anything else in any of the threads.
In any case, why was it even necessary to split the thread? If this is simply going to be "EnABL 2" with any and all aspects allowed (as long as it "might" do something), of what use is it if any and all aspects are to be allowed? Minor points, fine. Extensive posts that are primarily on "technique" have a thread dedicated to them. Add a link to posts in the other thread, that was how it was suggested it be done (by the moderators, I believe) before the split occurred.
So how about a comment on john's post? Why is it that a post with such significant implications is left without response by most? Someone, anyone, provide your analysis of the hard data. Hard data gets short shrift here. Is it because it's all been contradictory?
Dave
dlr said:
dlr,
1) None of my posts in this technical thread have been subjective.
2) You had the opportunity to put my claims re baffle and ports to the test - you declined and made excuses.
Daygloworange has decided to put EnABL on baffles and ports to the test.
Personally, I'm delighted to have my 'unsupported subjective listening' put to the test by objective measurement.
It will be very interesting to see how this 'hard data' is interpreted.
Cheers,
Alex
Baffle diffraction
I have looked at whether an obstacle of the order of an Enable patch could alter diffraction.
Description of the test set up:
Vifa MG10 flush mounted on large 23" x 25" baffle.
A single ring of "pin strip" tape was applies in a circular pattern 8 1/2" in diameter centered around the driver. Tap is 1/8" wide, 0.0035" thick (height off the baffle).
Mic positioned 5 1/2" from driver dust cap on axis.
This yielded a propagation delay of about 0.423 msec from driver AC to mic, and about a 1 msec delay before any diffraction form the tap pattern would reach the mic.
A circular pattern was chosen because it maximized the effect of diffraction from the tape.
The pattern was applied and the measurement made. Without moving anything the tap was removed from the baffle and a second measurement made.
The following figures speak for them selves.
Upper: Impulse response for no ring, white, and with ring, brown.
Lower: over lay of the two plots above.
Next plot, same as above but vertical scale magnified 5 times.
Next plot, same as first but vertical scale magnified 50 times. Only overlay shown.
This last plot is an attempt to quantify the errors in repeated measurements. This is an overlay of two successive measurements made without the rings with the vertical scale magnified 50 time. Since full scale is -34dB it is apparent that any differences are at lease another factor of ten below that or better that -54dB.
In case you miss the point, there aren't any differences due to the diffraction ring. Painting little dashes on you baffle will do nothing.
There is one another conclusion which can be drawn form this test. Enable patches applied to any surface, driver, port.... are too small to result in any significant disruption of acoustic wave propagation across a surface. This is more evidence to support the idea that application of enable paint results only is altered cone vibration due to a change in cone properties after application. It also sort of puts to rest the idea that there is something different happening in some kind of BL (which has never been defined).
I have looked at whether an obstacle of the order of an Enable patch could alter diffraction.
Description of the test set up:
Vifa MG10 flush mounted on large 23" x 25" baffle.
A single ring of "pin strip" tape was applies in a circular pattern 8 1/2" in diameter centered around the driver. Tap is 1/8" wide, 0.0035" thick (height off the baffle).
Mic positioned 5 1/2" from driver dust cap on axis.
This yielded a propagation delay of about 0.423 msec from driver AC to mic, and about a 1 msec delay before any diffraction form the tap pattern would reach the mic.
A circular pattern was chosen because it maximized the effect of diffraction from the tape.
The pattern was applied and the measurement made. Without moving anything the tap was removed from the baffle and a second measurement made.
The following figures speak for them selves.
Upper: Impulse response for no ring, white, and with ring, brown.
Lower: over lay of the two plots above.
An externally hosted image should be here but it was not working when we last tested it.
Next plot, same as above but vertical scale magnified 5 times.
An externally hosted image should be here but it was not working when we last tested it.
Next plot, same as first but vertical scale magnified 50 times. Only overlay shown.
An externally hosted image should be here but it was not working when we last tested it.
This last plot is an attempt to quantify the errors in repeated measurements. This is an overlay of two successive measurements made without the rings with the vertical scale magnified 50 time. Since full scale is -34dB it is apparent that any differences are at lease another factor of ten below that or better that -54dB.
An externally hosted image should be here but it was not working when we last tested it.
In case you miss the point, there aren't any differences due to the diffraction ring. Painting little dashes on you baffle will do nothing.
There is one another conclusion which can be drawn form this test. Enable patches applied to any surface, driver, port.... are too small to result in any significant disruption of acoustic wave propagation across a surface. This is more evidence to support the idea that application of enable paint results only is altered cone vibration due to a change in cone properties after application. It also sort of puts to rest the idea that there is something different happening in some kind of BL (which has never been defined).
Re: Re: Baffle diffraction
That is the point. If there were any changes due to diffraction, they would appear as changes in the impulse response at the vertical line labeled "path length delay for diffraction ring". As is evident, there is no change in the impulse response.
Dave
soongsc said:
That is the point. If there were any changes due to diffraction, they would appear as changes in the impulse response at the vertical line labeled "path length delay for diffraction ring". As is evident, there is no change in the impulse response.
Dave
Re: Re: Re: Baffle diffraction
I mean I don't see the baffle edge diffraction inpulse. That is what we really want to change. I don't think the pattern should create new diffraction impulses that are obviously measurable, and thus the data is data presented by John K is what I would expect. But we should look at the changes in the baffle edge diffraction impulse.dlr said:
Re: Re: Baffle diffraction
George, you really make me wonder what you are looking at. You can see the effect of the diffraction from the diffraction ring in the plots because there isn't any effect that is greater than maybe -60dB. I can't show you something that doesn't exist. There is no edge diffraction because the baffle is large the edge diffraction would be at a much later time. I'm sure that may not sit well with some. They will ask, how can this show that edge diffraction isn't changed by enable patches. In response I would say if you don't understand, then you don't understand acoustics. Acoustic waves don't take evasive action. They don't see a change in a surface (enable patch or baffle edge) until they get there. So if a ring about the dimensions of an enable patch is place away from the baffle edge and has no effect was so ever (to -60dB or more) on the resulting impulse response, thus no effect on the wave propagation, then it won't have an effect if placed nearer the edge either. There is no room for argument. The intent of this experiment is precisely to remove the effect of the edge so that the effect (or lack thereof) of the patches can be observed independently. The conclusion is irrevocable. A 1/8” wide, 0.0035” high bump on a surface is invisible to an acoustic wave in the audible frequency range. It won't alter the wave that reaches the edge and it won't alter any wave generated by the edge that propagated back across the patch.
No need to discuss it further.
soongsc said:
George, you really make me wonder what you are looking at. You can see the effect of the diffraction from the diffraction ring in the plots because there isn't any effect that is greater than maybe -60dB. I can't show you something that doesn't exist. There is no edge diffraction because the baffle is large the edge diffraction would be at a much later time. I'm sure that may not sit well with some. They will ask, how can this show that edge diffraction isn't changed by enable patches. In response I would say if you don't understand, then you don't understand acoustics. Acoustic waves don't take evasive action. They don't see a change in a surface (enable patch or baffle edge) until they get there. So if a ring about the dimensions of an enable patch is place away from the baffle edge and has no effect was so ever (to -60dB or more) on the resulting impulse response, thus no effect on the wave propagation, then it won't have an effect if placed nearer the edge either. There is no room for argument. The intent of this experiment is precisely to remove the effect of the edge so that the effect (or lack thereof) of the patches can be observed independently. The conclusion is irrevocable. A 1/8” wide, 0.0035” high bump on a surface is invisible to an acoustic wave in the audible frequency range. It won't alter the wave that reaches the edge and it won't alter any wave generated by the edge that propagated back across the patch.
No need to discuss it further.
Re: Baffle diffraction
G'day john k,
There are a couple of points of difference with what you have tested and my application of EnABL to baffles:
- for a baffle of 23" x 25" I would be using a block size of 1" x 1/2"
- the EnABL pattern would be applied 1/2" in from the edge of the baffle
- I always use two pattern rings, not a single ring
- the differences as heard are at the listening position, not close to the driver.
I don't question your results, but the method used to test in this instance doesn't seem (to me) to correspond with how I am applying EnABL.
The measurement shows the impact of the tape in the middle the baffle, not at the edge of the baffle.
I have found that laying a plain strip of Scotch magic tape on a baffle edge makes no audible change.
Yet when I apply magic tape with the EnABL blocks stuck on top, there is an audible change.
Cheers,
Alex
G'day john k,
There are a couple of points of difference with what you have tested and my application of EnABL to baffles:
- for a baffle of 23" x 25" I would be using a block size of 1" x 1/2"
- the EnABL pattern would be applied 1/2" in from the edge of the baffle
- I always use two pattern rings, not a single ring
- the differences as heard are at the listening position, not close to the driver.
I don't question your results, but the method used to test in this instance doesn't seem (to me) to correspond with how I am applying EnABL.
The measurement shows the impact of the tape in the middle the baffle, not at the edge of the baffle.
I have found that laying a plain strip of Scotch magic tape on a baffle edge makes no audible change.
Yet when I apply magic tape with the EnABL blocks stuck on top, there is an audible change.
Cheers,
Alex
Protocol
In the interest of maybe helping those testing...
Here is a simplistic 4 person test protocol
4 people to determine if EnABL'ing makes a difference by listening
Two possible outcomes
- makes a difference (+) (reject null hypothesis, makes a difference)
- Does not make a difference (-) (do not reject the null hypothesis, no difference)
Sixteen possible results
++++ +++- +--+ --+-
-+++ --++ +-+- -+--
+-++ -+-+ ++-- +---
++-+ -++- ---+ ----
If you set the criteria that the only result acceptable as significant is all respondents report hearing a difference, then only the ++++ result is accepted.
Using this, the probability of an alpha error (rejecting the null, false positive) would be .0625
So, with 4 test subjects using all reporting hearing a difference as a criteria, there is a 1 in 16 chance of saying there is a difference when in fact there is no difference.
John L.
In the interest of maybe helping those testing...
Here is a simplistic 4 person test protocol
4 people to determine if EnABL'ing makes a difference by listening
Two possible outcomes
- makes a difference (+) (reject null hypothesis, makes a difference)
- Does not make a difference (-) (do not reject the null hypothesis, no difference)
Sixteen possible results
++++ +++- +--+ --+-
-+++ --++ +-+- -+--
+-++ -+-+ ++-- +---
++-+ -++- ---+ ----
If you set the criteria that the only result acceptable as significant is all respondents report hearing a difference, then only the ++++ result is accepted.
Using this, the probability of an alpha error (rejecting the null, false positive) would be .0625
So, with 4 test subjects using all reporting hearing a difference as a criteria, there is a 1 in 16 chance of saying there is a difference when in fact there is no difference.
John L.
A little more baffle...
Here is an additional measurement. This time, same MG10 driver in same 23" x 25" baffle with same 8 1/2" ring, 1/8" wide, 0.0035" high. But now the mic is flush mounted in the baffle 1" outside the ring. That is, the mic is measuring the impulse associated with the surface acoustic wave as it propagates across the baffle surface. One addition, I also measured the result for a 1/8" wide x 1/8" high ring made of Mortite.
White and orange are with and without the Enable like ring. Dark blue is with the Mortite ring. Again, the scale is linear blown up by a factor of 100 vertically. The top of the plot corresponded to -40dB relative to the initial impulse peak. Note that the white and orange are just about identical. No changes greater than approximately -60dB and that may well be in the noise. Also note that the 1/8" high Mortite ring doesn't even have drastic effects. Enable like rings do not effect the wave propagation over the surface in any audible manner. There are no “BL” effects.
Here is an additional measurement. This time, same MG10 driver in same 23" x 25" baffle with same 8 1/2" ring, 1/8" wide, 0.0035" high. But now the mic is flush mounted in the baffle 1" outside the ring. That is, the mic is measuring the impulse associated with the surface acoustic wave as it propagates across the baffle surface. One addition, I also measured the result for a 1/8" wide x 1/8" high ring made of Mortite.
An externally hosted image should be here but it was not working when we last tested it.
White and orange are with and without the Enable like ring. Dark blue is with the Mortite ring. Again, the scale is linear blown up by a factor of 100 vertically. The top of the plot corresponded to -40dB relative to the initial impulse peak. Note that the white and orange are just about identical. No changes greater than approximately -60dB and that may well be in the noise. Also note that the 1/8" high Mortite ring doesn't even have drastic effects. Enable like rings do not effect the wave propagation over the surface in any audible manner. There are no “BL” effects.
Re: A little more baffle...
One of my tests years ago used the hemispherical, plastic, self-stick feet, ones 1/4" and 1/2" diameter at the base. I put them all along the edge of the baffle and also in two successive circular patterns around a tweeter. I gave up that approach when it provided no significant change in the diffraction other than the double circular one making things worse due to close proximity to the tweeter.
I think I still have those measurement files from back around 2001-2002. If I find the files, I'll post them.
Good work, John.
Dave
john k... said:
One of my tests years ago used the hemispherical, plastic, self-stick feet, ones 1/4" and 1/2" diameter at the base. I put them all along the edge of the baffle and also in two successive circular patterns around a tweeter. I gave up that approach when it provided no significant change in the diffraction other than the double circular one making things worse due to close proximity to the tweeter.
I think I still have those measurement files from back around 2001-2002. If I find the files, I'll post them.
Good work, John.
Dave
Re: Re: Baffle diffraction
I don't think anyone here would argure thaty 1" x 1/2" block of what ever material you are using would have an effect. I certainly never would. But I'd would not place that in the catagory of an Enable process, unless by Enable it is meant any adhoc baffle, port, driver treatment... that migh alter something.
But the idea that a 0.0035" tall application of paint to anything (Baffle, port, cone, dome or a tweeter) will have any effect at all on the surface wave in the audible frequency range,that is in any way audible is rediculous. Let's put this nonsense about BLs etc to rest once and for all. Applied to a driver it is all the effect of the altered cone properties/vibration and resulting alteration in frequency response, and perhaps, changes in directivity at higher frequencies.
Alex from Oz said:
I don't think anyone here would argure thaty 1" x 1/2" block of what ever material you are using would have an effect. I certainly never would. But I'd would not place that in the catagory of an Enable process, unless by Enable it is meant any adhoc baffle, port, driver treatment... that migh alter something.
But the idea that a 0.0035" tall application of paint to anything (Baffle, port, cone, dome or a tweeter) will have any effect at all on the surface wave in the audible frequency range,that is in any way audible is rediculous. Let's put this nonsense about BLs etc to rest once and for all. Applied to a driver it is all the effect of the altered cone properties/vibration and resulting alteration in frequency response, and perhaps, changes in directivity at higher frequencies.
Belief and interpretations
Seems to me there are certain belief systems evidently occurring here that are not going to accept factual data unless supportive of the presumptive improvements being touted.
No amount of empirical data will be deemed adequate to sway such beliefs. That's too bad.
John K.'s data looks pretty definitive.
John L.
soongsc said:
Seems to me there are certain belief systems evidently occurring here that are not going to accept factual data unless supportive of the presumptive improvements being touted.
No amount of empirical data will be deemed adequate to sway such beliefs. That's too bad.
John K.'s data looks pretty definitive.
John L.
John K,
Thanks for the plots. Interesting, and given your application and method, sure doesn't look like an effect as far as my limited understanding of this stuff. I'll continue to listen to the discussion.
Dave, not really disingenuous - more like cheeky, trying to bring some levity. Note the smilie wink! Plus, I didn't say anyone said NOTHING happens, just virtually nothing (relative to audibility), but maybe I've misunderstood what some people are saying. Is everyone saying there IS or COULD BE a dramatic change due to EnABL?
Carl
Thanks for the plots. Interesting, and given your application and method, sure doesn't look like an effect as far as my limited understanding of this stuff. I'll continue to listen to the discussion.
Dave, not really disingenuous - more like cheeky, trying to bring some levity. Note the smilie wink! Plus, I didn't say anyone said NOTHING happens, just virtually nothing (relative to audibility), but maybe I've misunderstood what some people are saying. Is everyone saying there IS or COULD BE a dramatic change due to EnABL?
Carl
John L,
I don't really hear anyone saying that Boundary Layer IS the mechanism. All I hear is that some are claiming that they hear a difference, even with it applied to baffles. I certainly don't know where to go next with this, but either you think those hearing a difference with baffle treatment are hallucinating and thus there's nothing more to add to that discussion (and at least relative to John K's plots, that looks true), or you believe they are hearing something and you then have to look at where to look for an explanation. I am interested in Soongc's questions though.
Carl
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