Exactly, and one of the earliest comes from Alexander himself. The hole pattern, on the edge of the horn exit is there for a reason, other than it's art deco resonance.
Bud
hmmnnn
Looks like the Shibboleth's are ahead of the Agnostics on this one... 😀
I s'ppose one of the reasons I'm not overly enthused by the wonders of EnABL is I don't hear any of the parasitic negative nuances attributed to full range and other cone drivers. Why? I don't listen to cone drivers anymore than I have to.
One of the primary reasons I switched to planar's was the extraordinary clarity, detail, and mellow rock solid presentation they deliver. (Lynn Olson's characterization as "fizzy, thin, screechy" notwithstanding, what the H*&^ was he listening to?)
Oh, and as an aside, it appears some of my planars have already been "treated" by the mfg. as part of their basic development....
So to the extent that EnABL'ing (or whatever) treatment improves the quality closer to planars (which includes ribbons), I'm all for it!
John L.
Looks like the Shibboleth's are ahead of the Agnostics on this one... 😀
I s'ppose one of the reasons I'm not overly enthused by the wonders of EnABL is I don't hear any of the parasitic negative nuances attributed to full range and other cone drivers. Why? I don't listen to cone drivers anymore than I have to.
One of the primary reasons I switched to planar's was the extraordinary clarity, detail, and mellow rock solid presentation they deliver. (Lynn Olson's characterization as "fizzy, thin, screechy" notwithstanding, what the H*&^ was he listening to?)
Oh, and as an aside, it appears some of my planars have already been "treated" by the mfg. as part of their basic development....
An externally hosted image should be here but it was not working when we last tested it.
So to the extent that EnABL'ing (or whatever) treatment improves the quality closer to planars (which includes ribbons), I'm all for it!
John L.
Re: hmmnnn
1. Low frequency range limited by displatecement.
2. Possibly not so linear increase in SPL due to displacement linearity range.
Thus this type of speaker works very nice when listening at a low level well within it's linear range.
Line source is the best kind of source IMO for average home listeing rooms. However, there are a few challanges:auplater said:
1. Low frequency range limited by displatecement.
2. Possibly not so linear increase in SPL due to displacement linearity range.
Thus this type of speaker works very nice when listening at a low level well within it's linear range.
First, it looks like those dots are for similar problems EnABL addresses or the rows of holes Lynn suggests at the edge of baffles.
Second , It kinda shows that planar speakers do have similar problems such as standing waves or your speaker maker wouldn't have incorporated the dots..fascinating to me..
Second , It kinda shows that planar speakers do have similar problems such as standing waves or your speaker maker wouldn't have incorporated the dots..fascinating to me..
staggerlee said:
What I proposed was too elaborate, just sprinkle powder right on the speaker.
I found similar thing here - Chladni plates
http://www.fas.harvard.edu/~scidemos/xml2html.cgi?section=ow#ow02.10
The phenomenae modified are are drum modes stimulated by continuous feed of sound energy into speaker membrane/diaphragm.
See:
http://www.kettering.edu/~drussell/Demos/MembraneCircle/Circle.html
http://www.kobushi.com/acoustics/index.html
http://www.tabla.com/tablaph1.html
Speaker diaphragm drum modes will be complicated by the impedance boundary where it joins the voice coil former.
(Also vibratory modes are stimulated in the dust cap but I haven't yet looked for vibratory modes of domes.)
http://www.aes.org/e-lib/browse.cfm?elib=6487
http://www.infinitysystems.com/home/technology/whitepapers/cmmd.pdf
http://www.audioxpress.com/magsdirx/voxcoil/addenda/media/mowry306.pdf
The Soundeasy guy points out that FEM analysis of a speaker is possible but that one really has to destroy the speaker to get all the elements for analysis.
http://www.interdomain.net.au/~bodzio/Cone_Break_Up.zip
It seems to me what we want is a quick and dirty (emphasis on quick) way of seeing the modes on the diaphragm in order to damp them or shift them to frequencies higher than utilized.
What we want is a picture we can use to correlate modes, frequency, amplitude with desirable and undesirable sound features. Here's an FEA picture
http://www.algor.com/news_pub/cust_app/loudsp/images/jbl4.jpg
Folk can measure diaphragm modes using laser interferometry - there was a fuzzy picture in that Infinity white paper - but that seems kind of out of our league.
So what about stroboscopic video? It's used all the time by laryngologists to examine vocal fold behaviour. Mechanics use strobe lights to set timing.
see here:
http://www.fas.harvard.edu/~scidemos/OscillationsWaves/ShatteringWineglass/ShatteringWineglass.html
I don't know if this kind of setup would actually show modes generated by low SPLs....
What sort of off-the-shelf stuff could be used to actually show and measure the deflection of the membrane?
See:
http://www.kettering.edu/~drussell/Demos/MembraneCircle/Circle.html
http://www.kobushi.com/acoustics/index.html
http://www.tabla.com/tablaph1.html
Speaker diaphragm drum modes will be complicated by the impedance boundary where it joins the voice coil former.
(Also vibratory modes are stimulated in the dust cap but I haven't yet looked for vibratory modes of domes.)
http://www.aes.org/e-lib/browse.cfm?elib=6487
http://www.infinitysystems.com/home/technology/whitepapers/cmmd.pdf
http://www.audioxpress.com/magsdirx/voxcoil/addenda/media/mowry306.pdf
The Soundeasy guy points out that FEM analysis of a speaker is possible but that one really has to destroy the speaker to get all the elements for analysis.
http://www.interdomain.net.au/~bodzio/Cone_Break_Up.zip
It seems to me what we want is a quick and dirty (emphasis on quick) way of seeing the modes on the diaphragm in order to damp them or shift them to frequencies higher than utilized.
What we want is a picture we can use to correlate modes, frequency, amplitude with desirable and undesirable sound features. Here's an FEA picture
http://www.algor.com/news_pub/cust_app/loudsp/images/jbl4.jpg
Folk can measure diaphragm modes using laser interferometry - there was a fuzzy picture in that Infinity white paper - but that seems kind of out of our league.
So what about stroboscopic video? It's used all the time by laryngologists to examine vocal fold behaviour. Mechanics use strobe lights to set timing.
see here:
http://www.fas.harvard.edu/~scidemos/OscillationsWaves/ShatteringWineglass/ShatteringWineglass.html
I don't know if this kind of setup would actually show modes generated by low SPLs....
What sort of off-the-shelf stuff could be used to actually show and measure the deflection of the membrane?
Hi Frank,
But is EnABL addressing membrane vibration problems, or, air motion induced incongruances at and around pressurise gradient boundaries ?
Hi John,
Do you know if that 'ice-drop' pattern along the planar is on the moving edge of the membrane itself, or along the front edge where it is already attached to the frame ?
_______
We don't even need to paint or touch a cone to reduce some of the dissonant peaks in reproduction; simply hold a small piece of cloth on a wire frame closely in towards the centre of a cone, and it does not even need to be dead centre either.
This can appear to change what sounds like radiated resonances, but it does not actually touch the cone at all and merely alters air motion in the region of a full-range cone centre, much as must do a phase plug.
Cheers ............ Graham.
But is EnABL addressing membrane vibration problems, or, air motion induced incongruances at and around pressurise gradient boundaries ?
Hi John,
Do you know if that 'ice-drop' pattern along the planar is on the moving edge of the membrane itself, or along the front edge where it is already attached to the frame ?
_______
We don't even need to paint or touch a cone to reduce some of the dissonant peaks in reproduction; simply hold a small piece of cloth on a wire frame closely in towards the centre of a cone, and it does not even need to be dead centre either.
This can appear to change what sounds like radiated resonances, but it does not actually touch the cone at all and merely alters air motion in the region of a full-range cone centre, much as must do a phase plug.
Cheers ............ Graham.
Graham Maynard said:
FrankWW's post is excellent, very informative, thank you. I especially like the description of the AES paper in the link. It directly addresses the situation without any superlative language:
This is the essence of any cone treatment. Serious study by qualified professionals have shown, years ago, the conditions and the methods of treatment, including some essentially little different than the EnABLE treatment. Drivers have resonances, that's the primary reason for driver coloration. The treatment is a distributed mass/damping pattern if the diaphragm itself is to be unchanged.
Please keep in mind and that I and others who questioned the veracity of technical claims have never said that nothing changes. We have questioned, I think correctly, the claims of some sort of unknown and unmeasurable changes. The AES paper alone is sufficient to put that to rest. The other references serve to enlighten further.
And this is no surprise whatsoever, the phase plug was going to be my example. There's nothing mystical nor unknowable about what occurs when mass is added to a surface nor when something is placed in such a way as to block sound transmission. It most definitely does make a change.
It's also readily measured by technology that has existed for more than two decades. It's just much more easily obtained by the general public now. For a phase plug (and any treatments) one must be careful to fully explain the change. It simply blocks the radiation on axes for which it is directly in the path. However, all of that energy is then re-directed to the off-axis. All of this is easily measured and documented. I have quite a few pages at my site that provide this evidence explicitly.
Can it make a change? Sure. Is it through mystical properties? No.
Dave
jlsem said:
The drivers are 25" long x ~2.5" across...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Graham Maynard said:
Hi Graham,
The pattern is inside of the attachment to the frame, the only points of attachment are along the solid edges 1/2" in from the frame edge. You can see a depression from film stretching just outside the "half moon" shaped pattern along the metallized edge where the dots beigin.
soongsc said:
I dunno, I get 112dB or so at my listening position with this setup, augmented of course with 2 sonosubs...I can't listen much over 107 dB or so anyway... and remember, this source drives the room @ 1/R thus filling the room much more evenly.
An externally hosted image should be here but it was not working when we last tested it.
John L.
HI Dave (dlr),
I personally wish you would SHARE discussion rather than trying to over-ride it before it gets going !
I wonder how you can be so sure that the changes people hear are due entirely to cone control, rather than air molecule control.
I should however be interested to know of the driver related to in your highlighted 'peakless diaphragm' quote ?
In relation to a phase plug, you stated
>> It simply blocks the radiation on axes for which it is directly in the path <<
I don't disagree that a phase plug has a measurable off-axis effect, but I should like to add that I have also observed (though cannot measure here) an 'on-axis' change related to the reproduction of transients on axis, and the shape/size of the plug affects both the transient attack capabilities and tonality.
Lowther have recently modified their FR driver phase plug/chassis shape relationships; same cone, but they claim improved front/back pressure loading.
Hi John,
So the 'ice drops are on the moving membrane. Thanks.
Cheers .......... Graham.
I personally wish you would SHARE discussion rather than trying to over-ride it before it gets going !
I wonder how you can be so sure that the changes people hear are due entirely to cone control, rather than air molecule control.
I should however be interested to know of the driver related to in your highlighted 'peakless diaphragm' quote ?
In relation to a phase plug, you stated
>> It simply blocks the radiation on axes for which it is directly in the path <<
I don't disagree that a phase plug has a measurable off-axis effect, but I should like to add that I have also observed (though cannot measure here) an 'on-axis' change related to the reproduction of transients on axis, and the shape/size of the plug affects both the transient attack capabilities and tonality.
Lowther have recently modified their FR driver phase plug/chassis shape relationships; same cone, but they claim improved front/back pressure loading.
Hi John,
So the 'ice drops are on the moving membrane. Thanks.
Cheers .......... Graham.
Graham Maynard said:
Actually, there ave been many posts by others mostly regarding perceptions. I've not jumped into any of this, though the thread tends to veer in this direction if there is no one taking issue. Excuse me for not waiting for others, next time I'll wait my turn. Who should I allow to precede me?
Frank's post provides significant references to valid, and in some of them, peer-reviewed expert evidence. That was a welcome contribution that was full of references that were not based on any conjecture whatsoever. I wished to highlight it and point out that there is more than adequate data that is counter to much of the basis of this thread, a number of recent posts included.
The acoustic output of the driver IS air molecule control. The only output from the driver is the air put into movement by the cone. The output we hear is the integrated sum of the vector output of the entire surface of the driver. The end result, what we hear, is measurable. Frank's post showed significant, serious and reliable proof of such separate from those of us in the thread and addressing much of what has been questioned.
Modification of the diaphragm materials, damping, thickness variation, profile and distributed weight have been used for years to achieve an acceptable acoustic output. There is nothing mystical in any of this. I still have never challenged that the acoustic output (frequency response) can be modified by the process. The effects are similar if not identical to some of those in the supplied references.
The details would be in the AES paper. These are by the experts in the field. In addition, a number of the other references are similar by other experts in the field such as Floyd Toole.
Of course there will be a change on-axis and of course it may be audible. If not, the phase plug would be superfluous. It's effects are well known and it's use is due to these known effects. Shape, size, position, distance, material, all have an impact. I have a page at my site that explicitly documents each one of these for phase plugs, all measured and detailed as carefully as I could. I'm not sure what your reference to this was meant to impart.
I don't doubt that a bit.
Dave
Hi, Graham,
Sound is a series of pressure gradients, isn't it?
You're thinking about air turbulence caused by speaker movement?
OK, Speed of sound varies according to density of air. How far would such gradients extend from surface of diaphragm?
If the diaphragm remained undeformed would not these effects, [air motion induced incongruances], tend to be uniformly distributed and probably cancel out and if they don't entirely cancel, be part of the diaphragm's "noise floor"? (My thinking is that this is the "non-distortion" or clean sound case).
I think these effects, if they exist in this case, must be very low level.
In the case of the diaphragm deforming into lumps of high and low energy emission, the level of turbulence effects might be audible, but would not the first cause be the deformation?
What sort of cloth? How thick? What size?
Grill cloth does act as a high frequency filter. Held how close to the speaker? Held in the axial direction or normal to it?
Sound is a series of pressure gradients, isn't it?
You're thinking about air turbulence caused by speaker movement?
OK, Speed of sound varies according to density of air. How far would such gradients extend from surface of diaphragm?
If the diaphragm remained undeformed would not these effects, [air motion induced incongruances], tend to be uniformly distributed and probably cancel out and if they don't entirely cancel, be part of the diaphragm's "noise floor"? (My thinking is that this is the "non-distortion" or clean sound case).
I think these effects, if they exist in this case, must be very low level.
In the case of the diaphragm deforming into lumps of high and low energy emission, the level of turbulence effects might be audible, but would not the first cause be the deformation?
What sort of cloth? How thick? What size?
Grill cloth does act as a high frequency filter. Held how close to the speaker? Held in the axial direction or normal to it?
dlr,
Would you please post the url for your complete site?
Just for reference, the paper over on the techno babble site was written in 1981 and altered slightly in 1987, somewhat before the "easily available to the general public" era.
Alexsander at RAAL has already warned me that the paper will have to be rewritten and when I obtain some definitive data from tests run on the pattern and results that show what is actually going on, I will be happy to do so.
The patent, based upon what has been described as a hoax in other threads was constructed in late 1993, still some time before readily available information was available to someone like me.
Does anyone have access to the departments involved in the college level investigations? Do they accept unsolicited requests for testing and information?
Bud
Would you please post the url for your complete site?
Just for reference, the paper over on the techno babble site was written in 1981 and altered slightly in 1987, somewhat before the "easily available to the general public" era.
Alexsander at RAAL has already warned me that the paper will have to be rewritten and when I obtain some definitive data from tests run on the pattern and results that show what is actually going on, I will be happy to do so.
The patent, based upon what has been described as a hoax in other threads was constructed in late 1993, still some time before readily available information was available to someone like me.
Does anyone have access to the departments involved in the college level investigations? Do they accept unsolicited requests for testing and information?
Bud
BudP said:
Certainly. The link is:
Dave's Speaker Pages
The pages of primary interest would probably be the one on Dayton Reference Series Tweeter RS28A-4 and the page Dayton Reference Series Midrange RS52NA-8.
My point was that much of what we know came from before the days of easy access, but that sufficient capability existed. MLS measurements techniques were not required to measure frequency response down to very low frequency, but it did require either an anechoic chamber or quiet outdoor facilities. Swept sine systems were capable back then to those on whose peer-reviewed papers much is now based.
To which site do you refer as "techno babble"?
Why re-written?
MLSSA (late 80's) and LMS (1993) were available then, I believe, but they certainly were much more expensive and not what most DIYers considered. I'll definitely grant that it was much more difficult and expensive back then.
Bud [/QUOTE]
I have found very detailed papers on http://www.klippel.de , see http://www.klippel.de/pubs/papers.asp and http://www.klippel.de/download/group.asp?group=35
On breakup modes measurements and their visualisation:
http://www.klippel.de/pubs/Klippel papers/Measurement_and_Visualization_Cone_vibration_06.pdf
It seems their techniques would identify any change in resonant structures after enABLing, assuming their system has enough resolution and any other parameter changes besides enabling (say, humidity) of the driver between measurements are controllable.
They offer driver measurement as a service besides rent/purchase of their test rigs (used by many top-notch companies according to the customer list), but I suspect such a complete laser scan will be quite expensive in either case, also assuming one would need several drivers of the same model/make to get reliable data.
BTW, my first experiment failed, that is, I cannot hear a change. I attribute this to the overall cheap quality of the test drivers which probably swamps the subtle effects and to my rather crude "craftmanship". But I don't put the topic aside completely.
- Klaus
On breakup modes measurements and their visualisation:
http://www.klippel.de/pubs/Klippel papers/Measurement_and_Visualization_Cone_vibration_06.pdf
It seems their techniques would identify any change in resonant structures after enABLing, assuming their system has enough resolution and any other parameter changes besides enabling (say, humidity) of the driver between measurements are controllable.
They offer driver measurement as a service besides rent/purchase of their test rigs (used by many top-notch companies according to the customer list), but I suspect such a complete laser scan will be quite expensive in either case, also assuming one would need several drivers of the same model/make to get reliable data.
BTW, my first experiment failed, that is, I cannot hear a change. I attribute this to the overall cheap quality of the test drivers which probably swamps the subtle effects and to my rather crude "craftmanship". But I don't put the topic aside completely.
- Klaus
Many patents are based on theory plus limited data. If one follows a patent to the dot, one will find that many are just not realizable because they require additional conditions for it to work.
Yet to see some data showing work results from other members here even though I do enjoy reading some of the technical babble. Very similar to political babble.
Klippel does to some really good research. I really wish they could push the tool a bit further to include FEA of acoustic waves radiated from the scanned surface. I have recommened this to them just prior to announcement of the scanner. If they can get a good FEA based FR data compliance against measured data, then it would be another breakthrough.
Yet to see some data showing work results from other members here even though I do enjoy reading some of the technical babble. Very similar to political babble.
Klippel does to some really good research. I really wish they could push the tool a bit further to include FEA of acoustic waves radiated from the scanned surface. I have recommened this to them just prior to announcement of the scanner. If they can get a good FEA based FR data compliance against measured data, then it would be another breakthrough.
Hi Frank,
All good questions !
A series of pressure waves ?
or a continuous wave.
Bud's vector comments stick in my mind.
Two other considerations in my mind relate to electromechanical voice coil related cone driving impedance, this allowing non-pistonic air motion close to the cone to cause a possible low level music induced group delay variation in time, ie. a haze of pre-propagation air motion at a band of frequencies which are related to cone size, shape, surface and termination.
Any modification of group delay should be measurable via swept sine examinations, but would still not relate directly to music reproduction, which is why I suggested simultaneous/differential/X-Y observations with parallel low Z drive.
Hi Dave,
Your last reply to me is appreciated, but it still does not seem to relate to the nature of EnABL.
Series impedance + modified surface coupling = different transduction of 'sound' in music time due to music induced alternations.
Cheers ............ Graham.
All good questions !
A series of pressure waves ?
or a continuous wave.
Bud's vector comments stick in my mind.
Two other considerations in my mind relate to electromechanical voice coil related cone driving impedance, this allowing non-pistonic air motion close to the cone to cause a possible low level music induced group delay variation in time, ie. a haze of pre-propagation air motion at a band of frequencies which are related to cone size, shape, surface and termination.
Any modification of group delay should be measurable via swept sine examinations, but would still not relate directly to music reproduction, which is why I suggested simultaneous/differential/X-Y observations with parallel low Z drive.
Hi Dave,
Your last reply to me is appreciated, but it still does not seem to relate to the nature of EnABL.
Series impedance + modified surface coupling = different transduction of 'sound' in music time due to music induced alternations.
Cheers ............ Graham.
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