Petrof Inharmonicity

[Alexander Galembo]

At 01:06 PM 3/4/98 -0500, you wrote:
>Del wrote:
>> No, you don't "hear" inharmonicity as such. As Bill points out, it will
>> have an effect on how the piano is tuned in that a piano with "high"
>> inharmonicity will be tuned somewhat sharper in the treble than will one
>> with "low" inharmonicity. However, inharmonicity by itself has no effect
>> on what you hear in terms of tone quality. 
>>
>Beg to differ on this point Del, on two counts. There is a tone difference
>that can be heard...and can be easily demonstrated with a spectrum
>generator. Set up a pure spectrum with maybe 50 partials and vary B
>(inharm.  coeff.). The change in tone is very noticeable as B is increased
>from zero to typical piano maximum. 

This was demonstrated in 1987 at the Acoustical Society of America meeting
by Reinholdt et al., but I am not agree with that completely. The tone will
change not because of the B change only, but also because of the change of
the spectral bandwidth that correlates with brightness of the tone. Change
of B in a 50-partials tone in across-piano limits for a bass region might
change spectral bandwidth twice or more. 

On other hand,  the inharmonicity and the soundboard (forming partly the
spectral envelope of the tone and his decay characterisytics) factors
compete in determining tone quality. In some cases the inharmonicity is
more important, in other - the spectral envelope.

Alex Galembo


Alexander Galembo, Ph. D.
NSERC-NATO Science fellow
Acoustics lab, Dept. of Psychology, Queen's University
Kingston ON  K7L3N6 
Canada

Tel. (613) 5456000, ext. 5754
Fax (613) 5452499
E-mail: galembo@pavlov.psyc.queensu.ca
URL   :  http://www.geocities.com/CapeCanaveral/Lab/8779/