Re: [Phys-l] Plastics for soundboards

[Bernard Cleyet <bernardcleyet@redshift.com>]

Oh!  I wasn't thinking.   Being an "expert" on pendula, where there  
is no intention of transferring energy to the atmosphere!   I was  
thinking only of hysteric and support loss in the material!

3000 seems very high!  Or I'm again very mixed up.  On the diatonic  
scale the next note would completely miss the resonance.

Is this oscillator driving a sound board? A several hundred increase  
in Q factor seemed high as it's about 10 for a Synchronome pendulum  
out and in a vacuum.  But its bob and rod are designed for minimal  
interaction with air while w/ a soundboard it's reversed!

bc doesn't want to add another iron to the fire.

On 2009, Mar 17, , at 17:07, curtis osterhoudt wrote:

> Remember that at very, very high Qs, the resonator will lose only a  
> very tiny fraction of its energy per cycle, and thus be almost  
> inaudible. I've done some preliminary measurements on a different  
> oscillator in and out of a vacuum chamber; the Q changes by a  
> factor of several hundred due to damping from the air. They're  
> wanting notes to last for quite a while, which of course means that  
> a given note can't be very loud (conservation of the mechanical  
> energy which is released from the vibration of a tine). At a  
> typical frequency of 1 kHz, they want a Q of something like 3000  
> (this is roughly what I found from the sound files they sent); I  
> hope to keep Q very roughly constant at all of their frequencies, with
>  maybe a few twiddles here and there, depending on what their  
> "expert" wants for his compositions. It may only be possible with  
> some tricky engineering.