Electrostatic AMT?

[mige0]

Originally Posted by DavidJanszen

Son of.

Yeah, I know.
But of the same format too?

Originally Posted by DavidJanszen

For now, as I have already said, I believe that compounding the air load, such as with pleats, will decrease the amplitude of membrane motion for a given amount of force, ...

Might be we are in a discussion about half full versus half empty – but I doubt.
I agree that there will be less excursion for a given initial radiating diaphragm area when folding this very ESL – so what?

Same effect if you put a horn in front of any driver - - - - - what does this tell us ?

You make the same mistake you did some postings ago (about balancing of break down voltage versus force obtainable when varying gaps) where you "forgot" to look at the second side of the equation.

Another paramount mistake of yours is the wild guess that ESAMT would only work respectively have its strength at the top end if any – way off !


Therefor my "back to the drawing board", David...

Originally Posted by DavidJanszen

...not that this is the only attenuation mechanism at work in an AMT.

As said before – I don't have the feeling you know about AMT .

Always sounds like you *have* to defend and put forward ESL and down talk anything else – bad salesman habit in the context of a DIY forum and not at all helpful ( IMO ) when it comes to discussion of something not been seen before like Keith's ESAMT invention.

Have you ever seen SPL or distortion plots of a new generation AMT or gave it a listen?
If so, you should be aware that both, sensitivity and distortion figures are nothing to complain about.

So either you know *nothing* about AMT or you are trying to tell us – what ???


Michael

[mige0]

Originally Posted by Keith Taylor

Keith

Guess again the basics got lost - no way to make something useful with no well defined 0 frequency (rest) position of the diaphragm - meaning there *must* be sort of resonant frequency too - cant see the therefor *necessary* spring here ???

Otherwise only a servo system is possible - meaning you have to sense and feed back the excursion and mimic a oscillating system synthetically - for each and every pleat separately of course

Michael

[kenpeter]

Yup, like slammin into XMAX at some unknown endpoint, its an unresolved unknown.
And the ribbon touching both stators (through dielectric) is at no specific Voltage.
You can't read back a position, you just pump in or suck out a number of coulombs
you want it to move... But move from where?

My suggestions involving Voltage offset are equally ridiculous until said Voltage has
some sort of spring to center and give something for those Volts to work against.
I'm open to simple suggestions not involving servos.

If the electrical width of each stator was of lesser at one end than the other???
Each tapered the opposite way... Would this tend to center the ripple in the middle
where the averaged capacitance is highest?

[DavidJanszen]

Originally Posted by mige0

I agree that there will be less excursion for a given initial radiating diaphragm area when folding this very ESL – so what?

Same effect if you put a horn in front of any driver - - - - - what does this tell us ?

An AMT is not like a horn. A horn takes a high impedance transducer and matches it to the much lower impedance of the open air. Pleating a diaphragm takes a low impedance transducer and presents it with an higher impedance load. Your assertion to the contrary is puzzling.

Originally Posted by mige0

Another paramount mistake of yours is the wild guess that ESAMT would only work respectively have its strength at the top end if any – way off !

I have no idea what you are referring to. I have never generalized, but been careful to relate statements about frequency cutoff to membrane span distances, tension, etc. Anything else must have been a misreading resulting from your inexplicable desire to cast me in a negative light.

Originally Posted by mige0

As said before – I don't have the feeling you know about AMT

.

I am sorry, but this statement is nonsensical in English. Please try again.

Originally Posted by mige0

Always sounds like you *have* to defend and put forward ESL and down talk anything else – bad salesman habit in the context of a DIY forum and not at all helpful ( IMO ) when it comes to discussion of something not been seen before like Keith's ESAMT invention.

I have not denigrated AMT's or defended ESL's. I have only stated what I think are the facts in relation to Keith's idea, which is what this thread is about. To do otherwise would be wrong, as you point out. Please stop with the personal accusations, try to understand what I really wrote, and please also do not confuse me with my company. I keep an open mind.

Originally Posted by mige0

Have you ever seen SPL or distortion plots of a new generation AMT or gave it a listen?
If so, you should be aware that both, sensitivity and distortion figures are nothing to complain about.

Who is complaining? You seem to be defending AMT's, when there has been nothing bad said about them.

Originally Posted by mige0

So either you know *nothing* about AMT or you are trying to tell us – what ???

I am trying to say that although ED AMT's work, I think ES AMT's will not. I have tried to say why I think this. That is all. You seem to be reading more into it than that. Please please please stop these digressions.

[mige0]

Originally Posted by DavidJanszen

A horn takes a high impedance transducer and matches it to the much lower impedance of the open air. Pleating a diaphragm takes a low impedance transducer and presents it with an higher impedance load.

Wow...
seems I never stop learning...

Michael

[DavidJanszen]

Originally Posted by mige0

As said before – I don't have the feeling you know about AMT

I get it, now. You think I do not know about AMT's.

How is that ED- AMT spreadsheet coming along?

[mige0]

Originally Posted by DavidJanszen

I get it, now. You think I do not know about AMT's.

Persuade the opposite - welcome at anytime...

Originally Posted by DavidJanszen

I was thinking it would just be written to derive the Lorenz force and the foil temperature rise from the essential parameters of the magnet's magnetization or magnetic moment and physical dimensions, magnetic gap width, the current, the foil thickness, dimensions, density, and conductivity, and the pleat depth and gap. I think it seems okay for this purpose to simplify by assuming the static field is at a perfect right angle to the current flow, and also to ignore the dynamics and assume DC current flow. Might be worth searching to see if anyone published such a thing already, though, which I have not done. Seems like it would be a great 2nd semester physics project for a smart kid.

Originally Posted by DavidJanszen

How is that ED- AMT spreadsheet coming along?

...eloquent like any Troll's name dropping - to be honest



Michael

[arend-jan]

This thread is going downhill fast..

Please shape up guys.

[Few]

Still hoping for an explanation of how one might improve on the impedance match between an ESL diaphragm and its air load...

Few

[Few]

I came across the following patent text while exploring acoustic impedance. The second half refers to the fact that the impedance of an air load can become too large when the air is overly confined. Seems pertinent---especially given the "All these theoretical results have been experimentally confirmed" statement.

Given the large forces typical of piezoelectric devices such as the PVDF example above, and the extremely low mass typical of current ESL diaphragms, I think the risk of the ES-AMT approach mucking up an inherently excellent diaphragm/load impedance match is high. I say this with regret, since I was quite excited about pursuing this approach myself, at one time. Nonetheless, if the impedance match truly is a problem, it seems like a deal-breaker.

Few

This paper investigates acoustic wave radiation from cylindrical polyvinylidene fluoride (PVDF) film mounted inside a concentric wall with a small air gap. In such a structure, propagation is allowed only in the gap between the film and the wall surface, and the wave propagates in the axial direction of the cylinder. The radiation impedance of the cylindrical transducer inside the concentric wall has been calculated using a one-dimensional propagation model. After calculating the mechanical impedance of the cylindrical PVDF film, the generated acoustic wave has been calculated as a function of frequency with various air gaps between the PVDF film and the wall. It has been found that the excited acoustic wave becomes stronger for a narrower air gap and shows a maximum at a specific air gap. This phenomenon has been explained as the match between the transducer impedance and the radiation impedance of the air gap. When the gap is too small, the radiation impedance exceeds the transducer's mechanical impedance, the acoustic wave radiation decreases with the decreasing gap, and the resonance frequency increases due to loading by the imaginary part of the excessive radiation impedance. All these theoretical results have been experimentally confirmed.