impedance and empericism

[Delwin D Fandrich]

----- Original Message -----
From: Conrad Hoffsommer <hoffsoco@martin.luther.edu>
To: <pianotech@ptg.org>
Sent: June 15, 2000 8:10 AM
Subject: Re: impedance and empericism


> Jimrpt,
>
> At 09:52 06/15/2000 EDT, you wrote:
>
> > ,...... If a source of pitch/tone were such that it gave off a
> >'measured'/'perceived' pitch of 440 hz at  70F , 10% RH and 22 mb AP
would
> >the 'perceived' pitch/tone be the same 440hz at 100F,  90% RH 26mb AP ?
And
> >the 'measured'?
>
>
> Gut feeling:
>
> Yes.
>
> You have not changed the source, only the speed at which the vibrations
> travel between source and receptor.  If the receptor were moving relative
> to the source, I could see where there might be a difference in
perception.
> (Hello, Dr Doppler, etc.)

---------------------------------------

Well, but we do change the source.

We tend to think of the bridge as a fixed termination point for the speaking
portion of the string.  It is not.  It moves in response to the vibrations
at the end of the string in a complex fashion.  That is, it moves, but it is
not always in phase with the force at the end of the string.  Without doing
a whole lot of thinking or analysis on this, I suspect that this could have
the effect of making the string act as if it were either very slightly
longer or shorter than it actually is depending on whether the bridge were
moving in phase with the end of the string or 180º out of phase with the
string.

Del