BudP said:
hmmnn
your point of view... but what is the "clear evidence" that the "event" is "lofted" into the turbulent region of the boundary layer?? You don't give any details of this evidence.. just some sort of implied "fact".
seems to me the only effect that the EnABL pattern would have on the "laminar" air boundary would be a slight thinning only where the EnABL pattern is located. The conformal layer would seem to only raise the layer of air that would comprise the "boundary layer" off the surface of the cone by the thickness of the coating. Not sure what this has to do with laminar vs. turbulent region? Lots of big words about energy transformations, boundary layers, bending waves, transmisssion line behavior, without a shred of external reference to theory of such and or how it applies. You simply seem to state this proposed hypothesis as fact.
really trying to grasp what you're trying to say, but John K.'s analysis makes alot more sense re: wavelength vs. cone behavior, energy propagation (or not).. etc.
John L.
John's post is the most logical and authoritative in the thread
That's been one my main criticisms. It's a laundry list of speculation.
The data presented by soongsc is in no way proof of any claims other than SPL changes. At this point I'm a bit stunned at the repeated claim that it is some sort of proof. It is, however, the type of change seen with added mass.
John's descriptions are straight forward, cogent, and logical in addition to being easy to grasp. It is exactly how I might have envisioned it in a mental image.
Dave
auplater said:
That's been one my main criticisms. It's a laundry list of speculation.
The data presented by soongsc is in no way proof of any claims other than SPL changes. At this point I'm a bit stunned at the repeated claim that it is some sort of proof. It is, however, the type of change seen with added mass.
John's descriptions are straight forward, cogent, and logical in addition to being easy to grasp. It is exactly how I might have envisioned it in a mental image.
Dave
Bud, I did not say the cone acts as a piston. I said the mechanism of cone motion is a bending wave initiated at the cone/VC junction. Then I said, to effect; if the wave length is long the resulting normal displacement of the cone is relatively uniform vs. radius. That doesn't mean it moves as a rigid piston, it means it approximates a rigid piston because the deviation for true piston behavior in negligible. I agree, whether or not the motion is pistonic or not is irrelevant.
That's a real stretch. The only thing that tracks the motion of the surface (treated or otherwise) is the air that is in contact with the surface. All energy is transferred there. As we move off the cone the pressure wave in air is a result of a balance between partical acceleration and the fluid stress tensor. The stress tensor includes viscous effects which are predominately shear stresses and normal stresses with are predominantly pressure gradients. The viscous terms are dissipative.
I'm not even clear as to what this sentence is supposed to mean, but I don’t think that is what ronc was saying at all. However, there is no way any energy transfer can be moved out of any boundary layer. Any such boundary layer only exists in the first place because there is a transfer of energy/momentum at the interface.
Laminar zone? As opposed to what other type of zone? Anyway, let’s suppose that I sort of by this (which I definitely do not). You’re trying to tell me that the enable pattern, applied over a very small percentage of the cone area, magically lifts the formation of the acoustic wave in air out of said boundary layer, not only in the vicinity of the pattern, but over the entire cone area?
I reiterate. The acoustic wave in air is only created by a transfer of energy from the moving surface to the air in contact with that surface due to the surface disturbance. Since the energy transfer is initiated at the surface, any resulting acoustic wave in the air muct be a result of the propagation of the surface disturbance through any boundary layer, what ever its form.
That's a real stretch. The only thing that tracks the motion of the surface (treated or otherwise) is the air that is in contact with the surface. All energy is transferred there. As we move off the cone the pressure wave in air is a result of a balance between partical acceleration and the fluid stress tensor. The stress tensor includes viscous effects which are predominately shear stresses and normal stresses with are predominantly pressure gradients. The viscous terms are dissipative.
I'm not even clear as to what this sentence is supposed to mean, but I don’t think that is what ronc was saying at all. However, there is no way any energy transfer can be moved out of any boundary layer. Any such boundary layer only exists in the first place because there is a transfer of energy/momentum at the interface.
Laminar zone? As opposed to what other type of zone? Anyway, let’s suppose that I sort of by this (which I definitely do not). You’re trying to tell me that the enable pattern, applied over a very small percentage of the cone area, magically lifts the formation of the acoustic wave in air out of said boundary layer, not only in the vicinity of the pattern, but over the entire cone area?
I reiterate. The acoustic wave in air is only created by a transfer of energy from the moving surface to the air in contact with that surface due to the surface disturbance. Since the energy transfer is initiated at the surface, any resulting acoustic wave in the air muct be a result of the propagation of the surface disturbance through any boundary layer, what ever its form.
What ronc is showing is that if you can move the transformation up out of the laminar zone, then the compression wave that is being created will more closely track the energy structure of the bending wave/transverse energy wave
Exactly.
Gee you guys type a lot! You can examine anything to death, but it ususlly comes down to simple actions/physics. Some of the greatest equations ever established were basically simple. Its very easy to make a question complicated but more difficult to make it simple.
The actions NOW that i stand back and look at them are not that complicated.
Ok lets try to make it simple: Any wave travelling over a surface imparts energy to the surface. By diverting the energy imparted there is less energy imparted to the surface. The surface now has a more neutral state of energy, The surface can now respond to an induced energy in a greater degree of accuracy wthout the alteration of an outside influence of a secondary later timed energy input.
ron
(this is about as much as i type)
Exactly.
Gee you guys type a lot! You can examine anything to death, but it ususlly comes down to simple actions/physics. Some of the greatest equations ever established were basically simple. Its very easy to make a question complicated but more difficult to make it simple.
The actions NOW that i stand back and look at them are not that complicated.
Ok lets try to make it simple: Any wave travelling over a surface imparts energy to the surface. By diverting the energy imparted there is less energy imparted to the surface. The surface now has a more neutral state of energy, The surface can now respond to an induced energy in a greater degree of accuracy wthout the alteration of an outside influence of a secondary later timed energy input.
ron
(this is about as much as i type)
Ron: After following this thread from the beginning, and getting pretty lost in the explanations/ speculations, I find your above post to be a "breath of fresh air"! For the technically challenged, but interested, like myself, Thanks!!ronc said:
Don
Hi John L,
Re your Post#1721; I thought Bud was suggesting an explanation rather than stating a proven one.
Surely we are still at the discussion stage here ?
I suggested that the energy air-side of the cone is reacting with the cone via the air layers and the raised voice coil reactance, this with respect to amplifier drive at the voice coil terminals. Any related change is going to change reproduction too.
(Maybe why PHY offer silver wire wound voice coils.)
There is a considerable pressure gradient in front of the centre of the cone and the linearity must change with frequency according to transverse wave motion, thus I don't see why dynamically induced interferences upon pistonic waves cannot be modified by surface treatment.
Hi Ron,
Re your Post#1724, and >> Any wave travelling over a surface imparts energy to the surface. <<
Then any wave losing energy to the cone cannot simultaneously fail to modify overall reproduction, even though the change might be at very low level wrt the fundamental ?
So when the air/cone/voice coil is reacting to already energised air flow and the waveform at the voice coil terminals changes ?
Surely energy activity can no longer accurately follow the new drive because of energy exchanges already in progress, and maybe this is what affects reproduction clarity.
Maybe EnABL improves the clarity by minimising the higher frequency parasitic air-side energy exchanges with the cone with respect to terminal drive ? There being a fractional time difference between drive and reproduction activity, and the final output being modified on an on-going basis by priorly energised energy exchanges, so the more complex the waveforms the more 'confused' the transduced output.
Cheers ........ Graham.
Re your Post#1721; I thought Bud was suggesting an explanation rather than stating a proven one.
Surely we are still at the discussion stage here ?
I suggested that the energy air-side of the cone is reacting with the cone via the air layers and the raised voice coil reactance, this with respect to amplifier drive at the voice coil terminals. Any related change is going to change reproduction too.
(Maybe why PHY offer silver wire wound voice coils.)
There is a considerable pressure gradient in front of the centre of the cone and the linearity must change with frequency according to transverse wave motion, thus I don't see why dynamically induced interferences upon pistonic waves cannot be modified by surface treatment.
Hi Ron,
Re your Post#1724, and >> Any wave travelling over a surface imparts energy to the surface. <<
Then any wave losing energy to the cone cannot simultaneously fail to modify overall reproduction, even though the change might be at very low level wrt the fundamental ?
So when the air/cone/voice coil is reacting to already energised air flow and the waveform at the voice coil terminals changes ?
Surely energy activity can no longer accurately follow the new drive because of energy exchanges already in progress, and maybe this is what affects reproduction clarity.
Maybe EnABL improves the clarity by minimising the higher frequency parasitic air-side energy exchanges with the cone with respect to terminal drive ? There being a fractional time difference between drive and reproduction activity, and the final output being modified on an on-going basis by priorly energised energy exchanges, so the more complex the waveforms the more 'confused' the transduced output.
Cheers ........ Graham.
I thought just the basic fluid dynamics textbook would make this obvious. Actually, the laminar boundary layer is now turbulent boundary layer, the thickness is reduced due to the flow variation gradient. This is just one effect of the pattern.BudP said:
soongsc said:
This is an amzing leap of faith... but whatever. To apply some proven tenet to a hypothesis, one would normally calculate the degree of change using said tenet and see if it has any relevance to the hypothesis being presented. This liability falls on the proponent, not those asking for explanations. Otherwise, we'd all be tilting at windmills. Not one proponent has presented any sort of theoretical or empirical information that this "boundary layer" transfer alteration has any significant amplitude, much less any sort of information regarding the "low level sonics" being modified to somehow "clean up" the drive signal.
Graham...
I thought we were discussing as well, but when statements such
as
"The pattern does not alter this event, though there is clear evidence that it alters the location within the boundary layer where this energy transform occurs."
are questioned, the chorus rises to shout "you shouldn't be asking that question! Don't you understand anything?" along with ad hominem insinuations about somehow ending the discussion.
Ronc
Where is the information to support the premise that these energy transformation alterations being discussed are actually taking place wrt sound level reproduction and improvement of low level signal distortions in the presence of the main drive? Is that info too sensitive for you to divulge? You know, like this effect represents .7% of the overall signal at -20 dB, or 2.3% at -30dB, or the Reynold's number in the presence of EnABL has increased dramatically from 600 to >4000, that sort of thing.
John L.
auplater said:
How much effort should be put into calculation really depends on two things IMO: 1) if there is a safety concern; 2) investment and return. Otherwise, if theory supports what we expect, and application also meets expectations, then from a designer point of view, we have wisely spend our time and effort.🙂
This is not a case of an acoustic wave impinging of the cone and transferring energy to it. The cone is transferring energy to the air and an acoustic wave in air is the result. What seems to be implied is 1) radiation form the cone and then re-absorption of that radiation. And 2) that enable treatment some how alters that re-absorption, not just locally, but over the entire cones surface. The bit that it alters the boundary layer to any significant degree over the entire surface of the cone just doesn’t fit the physics.
But even accepting that premises it doesn’t discount the effects of added mass which will have a direct affect on the vibration of the cone and wave propagation within the cone. Before some secondary, higher order, esoteric effects which supposedly alter the transmission of energy between the air and the surface are considered, the first order effects of added mass, and perhaps altered stiffness and damping, along with the inhomogeneities resulting form localized treatment should be considered. s it was said, keep it simple. Why delve into the complexities of pseudo physical argument and dismiss the obvious? Keep is simple is fine, but so is Be real!.
What has been described is spurious energy absorbed into the cone corrupting the cone motion. It has been postulated that redirection of this spurious energy will leave the cone is a more neutral state allowing the surface to respond more purely the input signal. However, this seems bogus from the start because the problem originates in the cone itself since it behaves as a poorly terminated transmission line with reflections form the terminations and potential excitation of resonant modes. That is, the cone doesn’t respond accurately to start with.
May I suggest looking at the vibrational characteristics of a cone before and after treatment using laser scans while the cone in contained in a vacuum chamber thus eliminating any transmission of acoustic energy at the surface?
But even accepting that premises it doesn’t discount the effects of added mass which will have a direct affect on the vibration of the cone and wave propagation within the cone. Before some secondary, higher order, esoteric effects which supposedly alter the transmission of energy between the air and the surface are considered, the first order effects of added mass, and perhaps altered stiffness and damping, along with the inhomogeneities resulting form localized treatment should be considered. s it was said, keep it simple. Why delve into the complexities of pseudo physical argument and dismiss the obvious? Keep is simple is fine, but so is Be real!.
What has been described is spurious energy absorbed into the cone corrupting the cone motion. It has been postulated that redirection of this spurious energy will leave the cone is a more neutral state allowing the surface to respond more purely the input signal. However, this seems bogus from the start because the problem originates in the cone itself since it behaves as a poorly terminated transmission line with reflections form the terminations and potential excitation of resonant modes. That is, the cone doesn’t respond accurately to start with.
May I suggest looking at the vibrational characteristics of a cone before and after treatment using laser scans while the cone in contained in a vacuum chamber thus eliminating any transmission of acoustic energy at the surface?
Maybe I am missing something. You folks keep talking about fluid dynamics and laminar and turbulent boundary layers. But for a speaker cone vibrating there is no net fluid flow, there is only the adjacent air (the fluid I guess) oscillating with a very small amplitude. Are you talking about extremely small air motions back and forth? Are you talking about very inefficient energy transfer from the cone to the air to produce sound so that the air provides some minimal amount of damping of the cone in return? What am I missing? For the midrange and higher frequencies, where I think the claims of improvement are focused, I just don't see many of these elaborate explanations making much sense. In my opinion, we are back to techno-babble. My almost 30 years of engineer experience has taught me that if an explanation sounds too complex, it is probably wrong.
Re: Re: All Previous posts
😀
This is becomming more like a cable and interconnects thread.14G-Dutch^ said:
😀
discussions
It's always fascinating to "seed" a discussion with in-context technical terminology related (or not) to the topic, then watch as said terminology is misappropriated ad hoc to support otherwise untenable positions and misunderstandings.
Perhaps the efforts thus far to scientifically "validate" EnABL as more than a possibly interesting tweak, nothing more, arise from just such meanderings.
John L.
It's always fascinating to "seed" a discussion with in-context technical terminology related (or not) to the topic, then watch as said terminology is misappropriated ad hoc to support otherwise untenable positions and misunderstandings.
Perhaps the efforts thus far to scientifically "validate" EnABL as more than a possibly interesting tweak, nothing more, arise from just such meanderings.
John L.
Surely energy activity can no longer accurately follow the new drive because of energy exchanges already in progress, and maybe this is what affects reproduction clarity
You hit the nail on the head, congrats. When you think about it its fairly simple. Any expanding wave imparts an energy to the surface its expanding from. This energy is microns in depth of the surface. Bud established a method of dispersing the energy so a leser degree energy met the next later timed wavefront.
Yall are making something complicated out of something simple.
Bud emailed me and notified me to the fact that any stamements i made ,concerning this subject, would be critized and there might be off forum remarks made about me and my findings. I really, truly in the depth of my heart and feelings, could care less.
My job is the advancement of technology in the steel production industry as well as the assurance that the end product meets the requirements of the applications. This means that when you drive by a pipeline or cross a bridge or even travel on a large ship that i probably had a hand in the safety of your crossing. The application of acoustical theory and physics in this question is minor compared to what i face in a day to day trial.
ron
(KISS is my objective)
You hit the nail on the head, congrats. When you think about it its fairly simple. Any expanding wave imparts an energy to the surface its expanding from. This energy is microns in depth of the surface. Bud established a method of dispersing the energy so a leser degree energy met the next later timed wavefront.
Yall are making something complicated out of something simple.
Bud emailed me and notified me to the fact that any stamements i made ,concerning this subject, would be critized and there might be off forum remarks made about me and my findings. I really, truly in the depth of my heart and feelings, could care less.
My job is the advancement of technology in the steel production industry as well as the assurance that the end product meets the requirements of the applications. This means that when you drive by a pipeline or cross a bridge or even travel on a large ship that i probably had a hand in the safety of your crossing. The application of acoustical theory and physics in this question is minor compared to what i face in a day to day trial.
ron
(KISS is my objective)
Ronc
Where is the information to support the premise that these energy transformation alterations being discussed are actually taking place wrt sound level reproduction and improvement of low level signal distortions in the presence of the main drive? Is that info too sensitive for you to divulge? You know, like this effect represents .7% of the overall signal at -20 dB, or 2.3% at -30dB, or the Reynold's number in the presence of EnABL has increased dramatically from 600 to >4000, that sort of thing.
Are you joking, its very basic.
In my opinion, we are back to techno-babble. My almost 30 years of engineer experience has taught me that if an explanation sounds too complex, it is probably wrong
I so very agree Martin. I cannot understand why you would want to complicate a simple question. I have found that if someone does not understand a principal then they resort to the standard techno babble.
ron
Where is the information to support the premise that these energy transformation alterations being discussed are actually taking place wrt sound level reproduction and improvement of low level signal distortions in the presence of the main drive? Is that info too sensitive for you to divulge? You know, like this effect represents .7% of the overall signal at -20 dB, or 2.3% at -30dB, or the Reynold's number in the presence of EnABL has increased dramatically from 600 to >4000, that sort of thing.
Are you joking, its very basic.
In my opinion, we are back to techno-babble. My almost 30 years of engineer experience has taught me that if an explanation sounds too complex, it is probably wrong
I so very agree Martin. I cannot understand why you would want to complicate a simple question. I have found that if someone does not understand a principal then they resort to the standard techno babble.
ron
Hi Ron,
Hence we could energise the air in front of the cone with a sine and then null the original waveform from microphone sensing to analyse any changes due to EnABL.
Steady sine will show changes after all dynamic activity has settled.
Changes following start-up and switch-off will show the effects due to dynamic change superimposed upon the (then known) sine distortion.
Minimising the error potential due to steady sine would be like reducing %THD.
Minimising error due to start-up/switch-off would be equivalent to reducing group delay influence upon transients.
Both being methods whereby the effects of different optimisation approaches may be examined for real world efficacy.
Cheers ........ Graham.
Hence we could energise the air in front of the cone with a sine and then null the original waveform from microphone sensing to analyse any changes due to EnABL.
Steady sine will show changes after all dynamic activity has settled.
Changes following start-up and switch-off will show the effects due to dynamic change superimposed upon the (then known) sine distortion.
Minimising the error potential due to steady sine would be like reducing %THD.
Minimising error due to start-up/switch-off would be equivalent to reducing group delay influence upon transients.
Both being methods whereby the effects of different optimisation approaches may be examined for real world efficacy.
Cheers ........ Graham.
Whenever there is a pressure gradient, there is airflow. Taken the wavelangth of sound in air and the pattern distance/size, I think the movement of air is not considered small.MJK said:
The way waves imparts energy to the cone depends on the frequency range and shape of the cone.
OK, so let us split the problem into two separate and weakly coupled solutions. Let us leave the cone modificatiosn aside for a minute and just look at what is going on to produce sound using a moving cone.
First, the voice coil exerts a sinusoidal motion that causes the cone to move in and out of the baffle. This motion could be uniform like a piston or it could be a function of relative position on the cone's surface if the cone is vibrating at a resonant frequency with an associated mode shape. The motion of the cone and the resonances of the cone are assumed to be not significantly influenced by the air at midrange or higher frequencies.
Second, a sound field is sent into the room by the motion of the cone. A standard trick in acoustics when trying to determine the sound field produced by a complex shape is to break it up into an infinite number of simple spherical sources distributed over the vibrating surface. The amplitide of each simple source's vibration is detemined by the local cone motion. Then we sum up the contribution of all of the simple sources to determine the resulting sound field. So at a particular location on the cone a simple source is vibrating and sending out a sound wave, remember there is no net flow only an oscillation in the air. The outgoing wave is transmitted into the room and also travels along the adjacent cone surface. The part of the wave that travels along the cone's surface exerts an oscillating pressure (positive and negative) on the cone surface which is really small compared to the force applied by the voice coil. This is a method that can be used to derive the acoustic impedance of a piston vibrating in a baffle and it is frequency dependent. At low frequencies it produces a mass load and at higher frequencies it produces a damping load. It is also a method that can be used to calculate the interference pattern produced by a piston in a baffle or the edge diffraction along a baffle boundary.
Those are my two models of the physics of sound produced by a driver, please correct me if I have missed a contribution or simplified the problem too much. There is no net fluid flow, the air motions are really quite small, which in my opinion eliminates Reynold's numbers and laminar or turbulent flow as point of discussion. The cone vibration at a given frequency produces a response at that same frequency, it does not produce a response at some other frequency.
If I have not stumbled or missed something I think that now the potential effects of modifying the driver with a coating or the Enable process can be assessed. If the driver cone is treated using the pattern of small raised "blocks" of paint, as seen in the Enable process, then I have to ask myself the following questions.
1) Does this pattern impact the simple source model I used to determine the sound field radiated by the moving cone? Based on the size of the "blocks" and the percentage of the cone surface area covered I am having a tough time seeing how this can be much of an impact on the transfer of cone vibration to sound moving away in the air. The sound wave moving along the surface of the cone would probably not even see the "blocks". Remember that at 1000 Hz the wavelength of wound 344 m/sec / 1000 Hz = 0.344 m/cycle or 344 mm/cycle. This dimension is huge compared to the size of the blocks. Even at 10000 Hz the wavelength is still huge compared to the blocks I have seen applied. I am not convinced that this is the mechanism for the improvements in sound claimed by people who have heard modified drivers. It would seem that the impact of the modification has to occur before the creation of the sound waves in the air and not be a modifier of the sound wave.
2) Could the addition of small amounts of material around the outer edge of the cone impact the resonant frequencies and mode shapes that are properties of the cone geometry and material? This to me sounds more plausible, by adding the blocks you are adding mass, stiffness, and damping to the cone which influences its vibration response. If the motion of the cone surface is changed, then the simple sources will vibrate with different magnitudes and change the summed sound field out in the room. The change is upstream of the sound wave being produced in the air. This arguement would also tend to invalidate claims of dramatic improvements due to Enabled cabinets or phase plus, the non vibrating surfaces.
Those are my thoughts and I think they tend to fall more in line with what Dave (dlr) has been saying in previous posts. I do have a pair of Enabled FE-126E drivers and I will also be listening to untreated drivers to see if I hear a difference. I have never said that the process does not produce an effect, the problems I have are with the explanations associated with the physics of the changes. As with most tweaks, the immediate claims are all very positive improvements which has happened before and unfortunately after a while the luster wears off. I suspect that the effect is going to be driver dependent and may not always be a positive impact.
As always, comments are welcome.
First, the voice coil exerts a sinusoidal motion that causes the cone to move in and out of the baffle. This motion could be uniform like a piston or it could be a function of relative position on the cone's surface if the cone is vibrating at a resonant frequency with an associated mode shape. The motion of the cone and the resonances of the cone are assumed to be not significantly influenced by the air at midrange or higher frequencies.
Second, a sound field is sent into the room by the motion of the cone. A standard trick in acoustics when trying to determine the sound field produced by a complex shape is to break it up into an infinite number of simple spherical sources distributed over the vibrating surface. The amplitide of each simple source's vibration is detemined by the local cone motion. Then we sum up the contribution of all of the simple sources to determine the resulting sound field. So at a particular location on the cone a simple source is vibrating and sending out a sound wave, remember there is no net flow only an oscillation in the air. The outgoing wave is transmitted into the room and also travels along the adjacent cone surface. The part of the wave that travels along the cone's surface exerts an oscillating pressure (positive and negative) on the cone surface which is really small compared to the force applied by the voice coil. This is a method that can be used to derive the acoustic impedance of a piston vibrating in a baffle and it is frequency dependent. At low frequencies it produces a mass load and at higher frequencies it produces a damping load. It is also a method that can be used to calculate the interference pattern produced by a piston in a baffle or the edge diffraction along a baffle boundary.
Those are my two models of the physics of sound produced by a driver, please correct me if I have missed a contribution or simplified the problem too much. There is no net fluid flow, the air motions are really quite small, which in my opinion eliminates Reynold's numbers and laminar or turbulent flow as point of discussion. The cone vibration at a given frequency produces a response at that same frequency, it does not produce a response at some other frequency.
If I have not stumbled or missed something I think that now the potential effects of modifying the driver with a coating or the Enable process can be assessed. If the driver cone is treated using the pattern of small raised "blocks" of paint, as seen in the Enable process, then I have to ask myself the following questions.
1) Does this pattern impact the simple source model I used to determine the sound field radiated by the moving cone? Based on the size of the "blocks" and the percentage of the cone surface area covered I am having a tough time seeing how this can be much of an impact on the transfer of cone vibration to sound moving away in the air. The sound wave moving along the surface of the cone would probably not even see the "blocks". Remember that at 1000 Hz the wavelength of wound 344 m/sec / 1000 Hz = 0.344 m/cycle or 344 mm/cycle. This dimension is huge compared to the size of the blocks. Even at 10000 Hz the wavelength is still huge compared to the blocks I have seen applied. I am not convinced that this is the mechanism for the improvements in sound claimed by people who have heard modified drivers. It would seem that the impact of the modification has to occur before the creation of the sound waves in the air and not be a modifier of the sound wave.
2) Could the addition of small amounts of material around the outer edge of the cone impact the resonant frequencies and mode shapes that are properties of the cone geometry and material? This to me sounds more plausible, by adding the blocks you are adding mass, stiffness, and damping to the cone which influences its vibration response. If the motion of the cone surface is changed, then the simple sources will vibrate with different magnitudes and change the summed sound field out in the room. The change is upstream of the sound wave being produced in the air. This arguement would also tend to invalidate claims of dramatic improvements due to Enabled cabinets or phase plus, the non vibrating surfaces.
Those are my thoughts and I think they tend to fall more in line with what Dave (dlr) has been saying in previous posts. I do have a pair of Enabled FE-126E drivers and I will also be listening to untreated drivers to see if I hear a difference. I have never said that the process does not produce an effect, the problems I have are with the explanations associated with the physics of the changes. As with most tweaks, the immediate claims are all very positive improvements which has happened before and unfortunately after a while the luster wears off. I suspect that the effect is going to be driver dependent and may not always be a positive impact.
As always, comments are welcome.
In real numbers, how far do you think the air moves for a typical driver vibrating at 1000 Hz or 10000 Hz with a 1 watt input? The air moves back and forth with no net displacement and I have to believe the absolute motion is very very small.
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