impedance and empericism

[Richard Moody]

----- Original Message -----
From: <JIMRPT@AOL.COM>
To: <pianotech@ptg.org>
Sent: Thursday, June 15, 2000 8:52 AM
Subject: Re: impedance and empericism



In a message dated 6/15/2000 3:33:28 AM, Ric wrote:

<<So a perfect problem for the "emperical" (measuring) scientists would be,
"does humidity affect frequency of tones, or any part of the frequency of
tones?">>

Jim...
Nah, this has long been answered by aeronautical and acoustical engineers.
i.e. <<"The velocity of sound in air at 32°F (0°C) is 1,089 ft/sec (331.9
m/sec), but at 68°F (20°C) it is increased to about 1,130 ft/sec (344.4
m/sec). *Sound travels more slowly in gases than in liquids, and more
slowly in liquids than in solids.*">>
 This excerpt is from the Encyclopedia of Acoustics and answers the above
question.  But begging the question, and addressing the problem of
measurement,...... 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'?


Ric....
I have thought of this.  If I am standing outside my window and a loud
speaker inside is playing a tone of 440 cps, do I hear 440 cps?  Some may
ask, why not?
And I answer, inside my house it is 70 degrees F and outside where I am
standing it is 10 degrees below zero.   We know that the temperature of the
tone producing device  affects the pitch.   We don't know that the
temperature of the air carrying that  the tone affects frequency in part
because the formulas for frequency of strings do not include air temperature
nor atmospheric pressure  or RH.
    Are you suggesting, "the velocity of sound affects frequency"?   Is the
tuning fork the same freq when clenched in your teeth, or listened to 3 feet
away on a sound board? Physists say sound travels faster through solids
such as your teeth and bones than gasses such as air.  But did they say a
change in velocity also changes the fequency? ---ric