The standard EnABL pattern works with shorter wave lengths, with metal cones, the wave length is longer than in paper cones. It's something that needs to be dealt with.Carlp said:
Dealing with domes and dust caps are a different issue because there is no surround. You either have to have a different method to dissipate the energy or prevent energy storage on the dome/cap without losing rigid connection with the VC former.
soongsc said:
Basically dlr is correct. But so are you. The wave is reflected because there is a change in the transmitting medium. It's a matter of strong the reflection is. All the data presented indicates the reflections would have to be very weak. The pattern isn't floating on the wave. It is bonded to the surface. The the surface deforms so must the patch. Another analogy might be a wave traveling inside a pipe. Then the wave encounters a change in diameter there is some type of reflection. The strength of the reflection is dependent on the change in diameter.
Carlp said:
Yes and know. The magnitude of the wave is dependent on the motion of the voice coil. How fast the wave travels and how fast it dissipates is related to the cone material, surround,... You may notice that I don't speaker about frequency because these wave occur at all frequencies. However, at low frequency where the wave length is much, much longer than the cone radius these reflections occur over a time which is much less than a single period of oscillation of the voice coil. The transverse wave in the cone extends over only a fraction of a cycle of oscillation. Thus what we see is the cone moving in and out as a piston. When the wave length gets small compared to the cone radius we see that several, or even many cycles of the transverse wave can exist in the cone at one time because the time it take the wave to reach the outer edge is much shorted than a period of oscillation. The wave propagation is the same but we separate the these as pistonic and bending wave motion.
We have the same thing with baffle diffraction. When wave length is long compared to baffle size we have the baffle step. When the wave length is short we call it diffraction. But the physics is the same. The result just looks different. And again with room acoustics. The thing is that waves basically behave in a fairly simple manner. What makes thing complicated is what happens when they encounter the boundaries of the finite domains they are propagating in.
Carlp said:
Don't confuse the Jordan hype with reality. There are a lot of things going on that we haven’t touched on, although dlr has mentioned some of them in the past. When we start talking about waves in solid, elastic materials the details get a lot more complicated than waves in air. Wave speed can be a function of frequency. Dissipation is a function of frequency (as it also is in air), and so fourth. Attempts to control radiating area with increasing frequency are typically about controlling directivity and off axis. Perhaps the best example, and really the only full range driver that I think is worth while, is a Manger. It's the only full range driver that I know of that truly addresses these problems as opposed to trying to make a conventional cone driver radiate over an extended range.
justblair said:
Yes, initially. I don't know what Bud is thing currently but I dismiss surface wave because my understanding of surface waves in an elastic medium is that they decay with depth and the length scale of that decay is of the order of a wave length and not particularly a function of amplitude. The thickness oc the cone at audible frequencies is never close to being on the order of a wave length thus motion at the surface of the cone must represent the motion across the entire cone, IMO.
No. The frequencies associated by the wave are not changed.
I think the answer to two makes this question irrelevant.
"could it be an analog to the dither insterted into a digital signal in a CD player?"
Dave, that's exactly what I meant with the ear being more sensitive to patterns than randomness. In fact, this would to some degree account for a sense of more clarity as the ear might be able to "pick" details from within this seemingly higher noise floor.
Bud, I've tried, without any luck, to google the Electro Voice you mentioned. I must say, I was not considering compression drivers. Will have to think about this. So this means that EnABL has worked on every cone driver so far. Interesting.
Dave, that's exactly what I meant with the ear being more sensitive to patterns than randomness. In fact, this would to some degree account for a sense of more clarity as the ear might be able to "pick" details from within this seemingly higher noise floor.
Bud, I've tried, without any luck, to google the Electro Voice you mentioned. I must say, I was not considering compression drivers. Will have to think about this. So this means that EnABL has worked on every cone driver so far. Interesting.
JacquesToo said:
Yes, eigen frequencies (resonances) may change. We talked about this with the string example inhomogenities change resonances). And we see it with some of the data. The frequencies of the resonances changes slightly after application of the pattern, the Q of the resonances change.... But all this keep coming back to what I see in the measurements. The patterns can change how the cone resonantes but do very little to stop it from resonanting. Standing waves doen't appear to be damped significantly, primarily they are just shifted around slightly in frequency Details get very complex.
I'm trying to put together a little simulation code to look at some of this in more detail. Not the exact problem, but something related so at least an idea of what happens is exposed. It will take a while.
I was a research scientist before I retired. Things like this present simple research projects to me. I work on them as long as they hold my interest. But I get bored easily, which is why I retired.
John and others,
Thanks for the patient explanations in response to my questions. I'm beginning to grasp pieces of this and it's quite interesting. But not being an engineer or physical scientist, I have to stumble through it. And the interactions here are so much more entertaining than a text book.
Carl
Thanks for the patient explanations in response to my questions. I'm beginning to grasp pieces of this and it's quite interesting. But not being an engineer or physical scientist, I have to stumble through it. And the interactions here are so much more entertaining than a text book.
Carl
john k... said:
The Manger is only a full-range driver in the same sense that something like a 3" Fostex FF85 is a full-range (and doesn't go as low as the 3"). They are both really mid-tweeters.
I have only had the opportunity to hear a manger once. As exectuted the speaker was a distaster.
Similarily i have heard the little Vifa you mention. Very smooth & even, but quite inefficient and lacking in dynamics. End result being a boring not very musical device (perhaps not inherent to the driver, but the execution)
dave
Plant 10's comment shows how different people hear differently.
The most perfect amplifier I ever designed and built ( as determined by lab measurements) sounded terrible to me. However some (repeat some) listeners liked it.
Since then, not being in the commercial world, I've always built to suit myself. Sure, measurements can be useful, but not the full story. I suspect the same applies here.
The most perfect amplifier I ever designed and built ( as determined by lab measurements) sounded terrible to me. However some (repeat some) listeners liked it.
Since then, not being in the commercial world, I've always built to suit myself. Sure, measurements can be useful, but not the full story. I suspect the same applies here.
justblair,
Not quite a surface wave. Rather a wave tip, on the surface of the diaphragm, from the originating transverse wave. This tip being the actual energy transform point, for what energy is in the body of the diaphragm. This traveling tip is all that the longitudinal wave has as it's energy source and so it forms, as the leading edge of a wave of pressure differential, and in conjunction with the tip, moves across the diaphragm. Both are moving considerably faster than the resultant longitudinal wave will move through the air, at an approximate right angle to this movement.
As the tip passes through the first pattern, it is raised up in it's height, relative to the cone surface and the gloss coating holds it at this height as it traverses the cone. All of the time it is traversing the diaphragm it is dumping energy into the leading edge of the compression wave, in the air, adjacent to the diaphragm.
At the outer pattern, the wave tip is forced to rise again and is in this condition when it slams into the surround, or exits the unbounded front surface edge of the diaphragm. In either case, the reflection from this drastic change in carrier medium is swamped by the energy of the transverse wave being already held off of the surface.
In an untreated cone the transverse wave is subducted into the surround, in both of the above instances, and some energy is reflected. The surround damps a large amount of the energy and reflects a portion. This reflected wave is a transverse wave and it's wave amplitude is likely to be considerably less than is needed to fully charge the diaphragm. As in other transverse waves in other energy systems, it becomes a skin effect wave. It's center line of energy raised towards the surface of the diaphragm, on both sides of the diaphragm, and the two resulting transverse wave forms, front and back, could be separated by an amount of material in the middle of the diaphragm.
The EnaBL pattern should be effective in suppressing these reflected waves, by mass damping, at the edge of the diaphragm. The closer to the surface these waves are held, the more effective the pattern should be.
Now, I am very interested in what John K can bring to modify this mental model, or dispense with it entirely. As I have often said, I am not particularly concerned with what the eventual description of the mechanisms of EnABL are. I am sure they are complex and I am sure they are active upon more than one factor.
The above model is the basis for my decisions upon where to place patterns, on a given surface to be controlled. I am happy to modify it, but, those modifications have to describe the actual effects of this pattern, applied in the places it is applied. And, included in those effects to be described, must be the subjective effects discussed pretty thoroughly in this thread.
Bud
Not quite a surface wave. Rather a wave tip, on the surface of the diaphragm, from the originating transverse wave. This tip being the actual energy transform point, for what energy is in the body of the diaphragm. This traveling tip is all that the longitudinal wave has as it's energy source and so it forms, as the leading edge of a wave of pressure differential, and in conjunction with the tip, moves across the diaphragm. Both are moving considerably faster than the resultant longitudinal wave will move through the air, at an approximate right angle to this movement.
As the tip passes through the first pattern, it is raised up in it's height, relative to the cone surface and the gloss coating holds it at this height as it traverses the cone. All of the time it is traversing the diaphragm it is dumping energy into the leading edge of the compression wave, in the air, adjacent to the diaphragm.
At the outer pattern, the wave tip is forced to rise again and is in this condition when it slams into the surround, or exits the unbounded front surface edge of the diaphragm. In either case, the reflection from this drastic change in carrier medium is swamped by the energy of the transverse wave being already held off of the surface.
In an untreated cone the transverse wave is subducted into the surround, in both of the above instances, and some energy is reflected. The surround damps a large amount of the energy and reflects a portion. This reflected wave is a transverse wave and it's wave amplitude is likely to be considerably less than is needed to fully charge the diaphragm. As in other transverse waves in other energy systems, it becomes a skin effect wave. It's center line of energy raised towards the surface of the diaphragm, on both sides of the diaphragm, and the two resulting transverse wave forms, front and back, could be separated by an amount of material in the middle of the diaphragm.
The EnaBL pattern should be effective in suppressing these reflected waves, by mass damping, at the edge of the diaphragm. The closer to the surface these waves are held, the more effective the pattern should be.
Now, I am very interested in what John K can bring to modify this mental model, or dispense with it entirely. As I have often said, I am not particularly concerned with what the eventual description of the mechanisms of EnABL are. I am sure they are complex and I am sure they are active upon more than one factor.
The above model is the basis for my decisions upon where to place patterns, on a given surface to be controlled. I am happy to modify it, but, those modifications have to describe the actual effects of this pattern, applied in the places it is applied. And, included in those effects to be described, must be the subjective effects discussed pretty thoroughly in this thread.
Bud
causation vs. effect
Could be the psuedo-orthogonality of the interstitial sites within the matrix interacting such that the tensor representing the transient interfacial tension with the application imparts a stressor such that the impinging flux upon said interface may refract a subsequent gradient upon the originating stimuli such that interaural artifacts are impacted.
Then again,it might just be personal preference...
John L.
Could be the psuedo-orthogonality of the interstitial sites within the matrix interacting such that the tensor representing the transient interfacial tension with the application imparts a stressor such that the impinging flux upon said interface may refract a subsequent gradient upon the originating stimuli such that interaural artifacts are impacted.
Then again,it might just be personal preference...
John L.
BudP said:
I beg to differ. It does no such thing unless you're referring to the gloss coated area itself only. Beyond that, it returns to the original diaphragm/air interface. The transverse wave imparts energy into the air at the interface with the air, wherever that interface is. For areas where there is an application of paint or anything else, it is at the surface of the that material and the air. For the rest or the diaphragm with no treatment, the vast majority of the surface, it is at the diaphragm/air interface. Enabl does not in any way "raise(d) up in it's height... and hold(s) it at this height as it traverses the cone".
After the wave passes the enabl points, the interface moves back down to the original diaphragm/air interface. The enabl application has no impact on the interface anywhere it is not applied other than some possible very small extension close to the enabl due to stiffening of the diaphragm near the enabl points. This will be a very small region.
In fact, if you applied the coating without the pattern, the interface would move up the same way, to the new interface, then back down again. There would be a different reflection (but still existing) and a different amount of mass (with different effects on the shifting of resonsances), but a similar response alteration.
No, this does not occur. The ONLY thing that the enabl is doing with the transverse wave directly is some small amount of reduction in wave energy due to the reflections that it creates where it is applied, as John's diagram shows. It is definitely not "in this condition" when it arrives at the surround. It is the same transverse wave as when it arrived at the enabl points, only with a small amount less total energy due to reflections and any slight change in the compression wave created at the enabl/air interface.
Again, nothing of the sort is occurring. The enabl application does absolutely nothing to what occurs at the surround/diaphragm junction. I thought that John had made this pretty clear in his descriptions.
It appears that you're saying "subducted" in the dictionary meaning, that is, subtracted, taken away, removed, whatever. This is not fully accurate because a large part of the energy is reflected, it is not subducted. This is also quite evident in all measurements provided to date.
I don't know what you mean to say here. The energy is what it is, there is no "charging". If it was not fully damped, it is reflected, that's it.
Whoa. As a reflected transverse wave, it is the same in both directions. It does not "become a skin effect wave", it remains the same in both directions. How did you come to this conclusion?
But it is not. All measurements provided show this to be the case.
You're basing your decisions on a faulty hypothesis as to effects of the application. The subjective effects discussed don't enter into the physics whatsoever and have no bearing on how one analyzes the changes. Demands to do so give the appearance of attempts to leave room to side-step any definitive results that John may present.
Dave
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