EnABL - Technical discussion

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Daygloworange said:
JohnK,

His name is Paul (can't remember his last name right at the moment). He and another friend of mine were collaborating on the wind turbine stuff.

I will contact him and show him the EnABL patent, and see if he would like to comment.

I'll pass along his contact info to you when I do get to talk to him. This guy is pretty well versed in airfoil shapes. He drives around with this rig on top of his car for testing, a la Burt Rutan, mind boggling stuff...

Can anyone point me to where I could find the patent info on EnABL, so I can pass it on to these guys?

Cheers

http://patft.uspto.gov/netacgi/nph-...5,304,746.PN.&OS=PN/5,304,746&RS=PN/5,304,746

John L.
 
Alex from Oz said:

Those who are willing to comprehensively test EnABL must be put under scutiny in relation to technical details around exactly what is tested and how.
There is no sensible reason not to have discussion and disclosure prior to testing.

Anyone who really wants to ensure the objectivity of this technical thread should be delighted to take this approach.

I fully agree Alex. No worries.

Cheers
 
john k... said:
I think it is fine if you want to test your approach, but my interest is with what Bud has defined as Enable. And I am really only interested in what enable can do when applied to a driver. My tests were never really aimed at diffraction or ports. That was an aside due to the responses posted here. The crux on my tests were, and remain, isolating an enable pattern, as would be applied to a driver, from cone vibration and studying the passage of acoustic wave over them.

What is appropriate here is, what ever is tested, is to report it as such. If you want to test scalloped edges and call it enable, fine. Just make sure you tell us about the edge treatment. If you want to stick a sock in a port and call it enable, fine. Just let us know whether the sock was cotton or wool. :)

G'day john k,

The crux of EnABL is the pattern itself.

The only differences between my application to port & baffles and what Bud has described as EnABL are:
1) no conformal coating
2) block material
3) number of block pairs

I think I have been very clear about my approach.

Cheers,

Alex
 
Daygloworange said:
Alex,

No need to jump the gun. I haven't gone ahead with anything yet.

Other than look at your spreadsheet, and confirm with RAW Acoustics that they would agree to test EnABL on baffles and ports, I haven't done anything. As I've mentioned, I've been too busy with work.

You can bet your bottom dollar that I won't go through all the effort of getting the patterns made, sent off for application and testing, only to have the results poo poo'd.

Since you are the one who has the most experience with these applications of EnABL, we will do it in such a way to best replicate your results.

No worries. I will consult with you first, before any work is done.


Cheers

Thanks Daygloworange,

You are the first person prepared to sensibly discuss and test the things I have been reporting.

I'm looking forward to working with you and others to get some useful answers.

Cheers,

Alex
 
Hi John K,

Your tests to date were excellent. However, they were for simple wavemotion over a flat surface.

You provided a link showing pressure representation for a cone driver with single frequency drive at a wavelength corresponding to cone diameter.

Look at the representative pressure lines where you have applied your 'EnABL' tests to date.

Are these anything like the (alternating) pressure regions arising at the cone surface or within the conicular volume prior to eventual wave launch from a baffle aperture ?

To state that your baffle test is relevent within a cone or port area must mean that you are making an 'assumption' that surface waves do not become abnormally polarised and develop a 'vector component' wrt to a surface or volume through which they pass due to localised pressure gradients; pressure gradients which might well be modified by EnABL patternation.

Of course what I have just written could be more low intelligence 'technobabble' from a poorly educated person who simply does not get it (maybe there were more comments stuck on my back which were not worth remembering), yet I cannot do any more than wait until opportunities arise to discuss without prematurely shooting from the hip.

John K; were you last two tests relevent to an air-side of cone (or port) situation ?

Cheers ............ Graham.
 
Graham Maynard said:
Hi John K,

Your tests to date were excellent. However, they were for simple wave motion over a flat surface.

But it wasn't "simple wave motion". It was two separate very complex (more so than any music) test signals as he pointed out. One an MLS which is anything BUT a simple wave motion, the other was a true impulse, also not simple wave motion. You should do some reading up on what constitutes both, your description ("simple wave motion") indicates significant lack of understanding of what they are. The test did what he intended, it isolated the effect to address the specific claim of alteration in a wave passing over, one of the fundamental claims Bud made originally. It somehow "launched" the wave off of the surface (any surface, not just a driver diaphragm). We now have the evidence that this clearly does not occur.

A claim was also made that lines, painted or otherwise, on a flat baffle on the order of the dimensions of enabl is so effective and makes such a dramatic change that baffle edge diffraction is eliminated. Yet John's measurements demonstrated conclusively that there is no basis in fact to this claim. Denial is still the order of the day.

I'm amazed at the level of denial by so many here. Everyone clamored for measurements, John provided them, but the end result is just more denial and as some also pointed out, claims would be made that the tests were deficient in some way. I fully expected this.


John K; were you last two tests relevent to an air-side of cone (or port) situation ?

I have no doubt that his answer will be yes. It was originally pointed out by a number of us here that there would be no significant change on a flat baffle as well, to the hue and cry of those hearing what they wanted to hear. Now that John's tests should have put that to rest, denial sets in. Again.

Amazing, simply amazing.

Dave
 
Graham Maynard said:
Hi John K,

Your tests to date were excellent. However, they were for simple wavemotion over a flat surface.

You provided a link showing pressure representation for a cone driver with single frequency drive at a wavelength corresponding to cone diameter.

Look at the representative pressure lines where you have applied your 'EnABL' tests to date.

Are these anything like the (alternating) pressure regions arising at the cone surface or within the conicular volume prior to eventual wave launch from a baffle aperture ?

To state that your baffle test is relevent within a cone or port area must mean that you are making an 'assumption' that surface waves do not become abnormally polarised and develop a 'vector component' wrt to a surface or volume through which they pass due to localised pressure gradients; pressure gradients which might well be modified by EnABL patternation.

Of course what I have just written could be more low intelligence 'technobabble' from a poorly educated person who simply does not get it (maybe there were more comments stuck on my back which were not worth remembering), yet I cannot do any more than wait until opportunities arise to discuss without prematurely shooting from the hip.

John K; were you last two tests relevent to an air-side of cone (or port) situation ?

Cheers ............ Graham.

I really don't think you are understanding this. All those pressure lines you see are just magnitude. They are computed from a model that in made up of many spherical sources.

http://www.silcom.com/~aludwig/Physics/Exact_piston/Generalized_multipole.htm

Each source radiates a time dependent sine wave excitation at the same frequency. The output of all sources is summed to obtain the pressure vs. time at any point in space yielding a pressure at each point given as P = M sin (wT+ phi). What is plotted is the amplitude of the sum at each point in space, M(Y,Z). What is missing here is the phase, phi. Given the phase we could write the expression for the time dependent pressure at any point and generate an animation of how the pressure waves (acoustic waves) propagate from the driver. If we chose a point on the baffle we would see a sinusoidal variation in the surface pressure vs. time at that point. The summation is possible because the physical process is linear. Being linear it means that if A is the output of the system to input a, and if B is the output of the system to input b, the A+B is the output if the input is (a+b). So if input a is the sine wave and input b is my MLS pulse then there is no doubt that the system output would be the sum of the two if they were input simultaneously. The output would be the MLS pulse superimposed on the sine wave. Since I have established that enable doesn't alter the output transfer function for the MLS pulse what I have actually established is that the output transfer function of this linear system is not altered by enable. Thus the output for the (sine + MSL) input, or any other input would look different form the pure MLS pulse (obviously), but there would still be no difference for treated and untreated surfaces.

What I have done is to demonstrate that a typical enable treatment, as would be applied to a driver, does not alter the propagation of an acoustic wave over a stationary surface. This is important because it can be argued mathematically that if it doesn't alter the propagation over a stationary surface it will also not alter the propagation over a vibrating surface. That is, any difference in the wave form due to vibration of the surface will be the same with or without the surface treatment provided the surface treatment doesn't alter the surface vibration. This last statement is very important because it effectively means that any observed differences in the sound radiated from a vibrating surface before and after treatment are not the result of differences in how waves propagate over the surface before and after treatment, which is the answer to your last question. All my recent tests are relevant to the air side of a cone or port with regard to wave propagation. Now I'm talking about applications similar to those I tested which are as would be applied to a driver cone. That is, where the height of the application is say 0.005" or less. We have seen the effects of making the height on the order of 0.125".

One last comment on another point. It was suggested that perhaps an MSL signal was not sufficient to examine this. dlr pointed out that an MLS signal is not just an impulse but a time continuous signal with specific format. This specific format allows the recorded MLS response to be converted to the system impulse response. FWIW, below is a figure showing a segment of an actual MSL signal (upper) and the impulse response computed form the signal (lower).

An externally hosted image should be here but it was not working when we last tested it.
 
BudP said:
John K.


IF you haven't been following this thread
http://www.diyaudio.com/forums/showthread.php?postid=1462805#post1462805

Then it should please you to see how many folks are obtaining the kit to apply EnABL. IF you have been, why isn't your name on the list already? ':D'


Bud


Ed LaFontaine said:
of questionable technical merit...;)...in one week after the initial post, 24 kits have been requested. Out of concern for inventory @ the suppliers, I'm pre-ordering a second batch of materials. This has swamped my expectations. I was warned by Bud.:D


That's good to hear. I hope to soon see some listening reports with a description of what types of systems are being treated and some indication of how the listening tests are conducted. It would certainly be nice if the subjective evaluations were made using objectively controlled conditions.

Why haven’t I ordered? I have about 16 bottles of the stuff sitting in my desk from my old model building days. What color would you suggest I use? :scratch:
 
john k... said:


...
One last comment on another point. It was suggested that perhaps an MSL signal was not sufficient to examine this. dlr pointed out that an MLS signal is not just an impulse but a time continuous signal with specific format. This specific format allows the recorded MLS response to be converted to the system impulse response. FWIW, below is a figure showing a segment of an actual MSL signal (upper) and the impulse response computed form the signal (lower).

An externally hosted image should be here but it was not working when we last tested it.
The radiation patern in real time depends on the slew rate and peak duration in each cycle we see in this graph. If the slew rate is high and the peak duration is short, the the radiation energy is more focused. As we see in the above graph, most parts of the signal are of a high slew rate short peak duration nature, and thus the pressure wave of such is more focused.
 
soongsc said:

The radiation patern in real time depends on the slew rate and peak duration in each cycle we see in this graph. If the slew rate is high and the peak duration is short, the the radiation energy is more focused. As we see in the above graph, most parts of the signal are of a high slew rate short peak duration nature, and thus the pressure wave of such is more focused.



Upper, a random selection of music. Lower, the same MLS signal.



An externally hosted image should be here but it was not working when we last tested it.
 
Hi John, John and DLR,

You all keep explaining aspects other than the main point I have consistently raised since I joined the original thread months ago.

In my last post I couched my stated concern as a suggestion that an assumption had been made. The explanatory posts above yet again suggest it is my failure to understand, but none of you have yet covered the aspect I repeatedly raise, so here I am seeking response in the form of a question.

Does a separately generated but coincidental pressure gradient normal (or acting at an angle) to the direction of simple wave motion progression not refract the direction of radiation when compared to passage through a region of negligible pressure variation, and therefore give rise to a vector component against any surface (cone/vent) bounding that pressure peak ?

Cheers ............. Graham.
 
Graham Maynard said:
Hi John, John and DLR,

You all keep explaining aspects other than the main point I have consistently raised since I joined the original thread months ago.

In my last post I couched my stated concern as a suggestion that an assumption had been made. The explanatory posts above yet again suggest it is my failure to understand, but none of you have yet covered the aspect I repeatedly raise, so here I am seeking response in the form of a question.

Does a separately generated but coincidental pressure gradient normal (or acting at an angle) to the direction of simple wave motion progression not refract the direction of radiation when compared to passage through a region of negligible pressure variation, and therefore give rise to a vector component against any surface (cone/vent) bounding that pressure peak ?

Cheers ............. Graham.

Graham

Maybe if you posed a question showing some analysis, rather than idle speculation...

as in...

"Folks, I have calculated a differential instantaneous pressure yielding a vector component normal to the propagating wavefront due to the imposed EnABL spots that may represent the perceived improvement, using (some sort of mathematical construct of your design) that indicates an error correction component not shown in steady state tests so far, and its value is (some percentage that you calculate) and I believe this is the cause for the effects heard"

rather than ask everyone else to come up with a defensive posture wrt your supposition(s) offered with no such support, we'd have something to work with. Will you do that? can you do that? Otherwise, there's nothing "technical' about your queries.

John L.
 
soongsc said:

Yep, except that the low frequency content is probably louder in most music.

So what. John could weight the mls to emphasize low frequency. Although this could improve LF resolution, it still would not change the analysis.

Graham Maynard said:
Hi John, John and DLR,

You all keep explaining aspects other than the main point I have consistently raised since I joined the original thread months ago.

In my last post I couched my stated concern as a suggestion that an assumption had been made. The explanatory posts above yet again suggest it is my failure to understand, but none of you have yet covered the aspect I repeatedly raise, so here I am seeking response in the form of a question.

Does a separately generated but coincidental pressure gradient normal (or acting at an angle) to the direction of simple wave motion progression not refract the direction of radiation when compared to passage through a region of negligible pressure variation, and therefore give rise to a vector component against any surface (cone/vent) bounding that pressure peak ?

Cheers ............. Graham.

Again, John's experiment is valid for 3 dimensional space. Arguing about not somehow accounting for some polarization effects along the axis of radation doesn't matter, since, well, the experiment is valid for 3d.

The results are the results. Accept them or not. Perceive a difference if you wish.

But there is no valid theory theory that suggests EnABL works, and no experimental evidence that suggest it does. And what limited experiments have been done, uh, only John k, has failed to support any differences. Does this mean that EnABL has been proven not to work? Well, not in a strict technical sense. We do lot's of things that haven't scientifically been proven to do anything.

If you want to treat your cones with EnABL, rock on! But don't kid yourself. There is no scientific justification as of yet, that this works.

I've often though we should rank audio technologies the way we rank therapies for medicine/cardiology-

Class I
should
is recommended
is indicated
is useful/effective/beneficial

Class IIa
is reasonable
can be useful/effective/beneficial
is probably recommended or indicated

Class IIb
may/might be considered
may/might be reasonable
usefulness/effectiveness is unknown/unclear/uncertain or not well established

Class III
is not recommended
is not indicated
should not
is not useful/effective/beneficial
may be harmful


On the basis of what's in these threads, the best you can give EnABL is a class 2b recommendation. I think you could defend a class 3 recommendation though as well. If the EnABL fad fades, and you've painted your expensive cones, well...
 
Graham Maynard said:
Hi John, John and DLR,

Does a separately generated but coincidental pressure gradient normal (or acting at an angle) to the direction of simple wave motion progression not refract the direction of radiation when compared to passage through a region of negligible pressure variation, and therefore give rise to a vector component against any surface (cone/vent) bounding that pressure peak ?

Cheers ............. Graham.

I'm not hedging here but rather than answer you question I would rather discuss its relevance. For the moment let us assume that the answer is yes, regardless of what the magnitude of such an effect would be. How does that impact the result? Whatever form of wave is generated by the result of this interaction, when incident upon an enable patch of the size represented by my experiments there will not be an affect on the wave propagation. Nothing in my tests requires that the wave traveling over the surface be generated in any specific way. In fact I used different driver in different tests (generating different wave forms) and found the same result. What was constant in the tests was the result that a 0.0035" high surface disturbance had no effect on wave propagation. A 0.125" high disturbance, on the other hand, had a very small effect. So assuming what you have said above is true, then with regard to enable altering the propagation of a wave over a surface, it doesn't change anything except the form of the incident wave.
 
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