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Old 3rd August 2012, 02:45 AM   #101
ondesx is offline ondesx  France
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Most of these noises may be attenuated or for some almost removed...

The issue is the spining frequency in clockwise and cc at very high frequencies taking into account the inertial moment of the device, moreover with an excitation at one end only... The torque will probably have severe consequences on the "membrane" each time the actuator changes its spining direction!
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Old 3rd August 2012, 02:55 AM   #102
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Agreed.
I can not see this thing working or producing any sound that is high fidelity in the sense that we are familiar with.
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Old 3rd August 2012, 09:08 AM   #103
ondesx is offline ondesx  France
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I'm not totally sure this thing will not produce good sound... I'll do some trials before any conclusion. The movement of the "membrane" could produce sound since it's a vibration. But the question now is how much "bending waves" of the material itself are "added" to the vibration of the device...

A very simple test is to change the material of the membrane...
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Old 3rd August 2012, 12:21 PM   #104
Remlab is offline Remlab  United States
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Julian Bunn used a square shaped pole of solid balsa. I think solid Rohacell foam would probably be the best 'diaphragm' material for this experiment.
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Old 3rd August 2012, 01:40 PM   #105
ondesx is offline ondesx  France
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The specs of a material aren't the same for the purpose of the Planot and for bending waves.... In the present case, one looks for a material having a very high Critical Frequency Fc.
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Old 3rd August 2012, 08:02 PM   #106
Remlab is offline Remlab  United States
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Quote:
Originally Posted by ondesx View Post
The specs of a material aren't the same for the purpose of the Planot and for bending waves.... In the present case, one looks for a material having a very high Critical Frequency Fc.
I remember years ago, an article by one of the NXT guys saying that the best material they had ever found for NXT exciter panels were sheets of laminated Rohacell and carbon fiber(Helicopter blade material), because of its extreme rigidity, internal damping properties and light wieght. Correct me if I'm wrong, but doesn't extreme rigidity equal high Fc?

http://www.rohacell.com/product/roha...s/default.aspx

http://www.cstsales.com/carbon_sandwich_panel.html

Last edited by Remlab; 3rd August 2012 at 08:20 PM.
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Old 3rd August 2012, 08:44 PM   #107
Remlab is offline Remlab  United States
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Excellent paper, if anyone is interested..
http://www2.eng.cam.ac.uk/~lhh26/fil...al%20Draft.pdf

Azima patent application, mentioning Rohacell..
http://www.christienellis.co.uk/imag...GB2357931A.pdf

Last edited by Remlab; 3rd August 2012 at 08:59 PM.
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Old 3rd August 2012, 09:45 PM   #108
sreten is offline sreten  United Kingdom
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Hi,

It simply doesn't work, it doesn't matter what you make it out
of, it still won't work, and having unobtanium available still won't
make any difference to the very simple physics being ignored.

rgds, sreten.
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Old 3rd August 2012, 09:50 PM   #109
planot is offline planot  United States
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Quote:
Originally Posted by sreten View Post
Hi,

It simply doesn't work, it doesn't matter what you make it out
of, it still won't work, and having unobtanium available still won't
make any difference to the very simple physics being ignored.

rgds, sreten.
What do you mean when you say it doesn't work?
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Old 3rd August 2012, 10:12 PM   #110
Remlab is offline Remlab  United States
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Quote:
Originally Posted by sreten View Post
Hi,

It simply doesn't work, it doesn't matter what you make it out
of, it still won't work, and having unobtanium available still won't
make any difference to the very simple physics being ignored.

rgds, sreten.
Sreten
It does work. Just not in a conventional sense (A kind of BMR?). Julian Bunn told me via email that he was surprised as to how well it worked, but he couldn't surmise exactly as to how it worked. Before NXT technology became available(With big names backing it up) , people would have laughed and made fun of the concept. We all need to admit though, that BMR type technologies will never, ever come close to sounding as good or as accurate as conventional technologies. Resonances in a reproducer are, by definition, flaws. Even if you balance them perfectly..

Seth

Last edited by Remlab; 3rd August 2012 at 10:38 PM.
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