Loud Overtones From String

[Jim Coleman, Sr.]

Hi JC:

The most common source for these obnoxious sounds is the convergence of
the longitudinal mode of vibration with a transverse mode of vibration.
Bass strings are infamous for them and on the very best pianos. When
these two modes of vibration nearly coincide, it causes a very high
peak of energy at that approx. frequency. Voicing will not eliminate
it. Only change to a different string configuration will change it.
That is expensive, and you may just get a different high peak. The
Baldwin patent on controlling longitudinal mode freqs. was a step in
the right direction. As far as I know, they are not using those strings
any longer because of the expense and lack of public appreciation.

Jim Coleman, Sr.

On Mon, 24 Jan 2000 JCSwafford@AOL.COM wrote:

> Dear List, 
> 
> I work for a dealer. I have received many complaints concerning loud 
> overtones from some unisons. Pianos of every manufacture have them I've 
> noticed, especially from the bass strings. Voicing the hammer and seating the 
> strings does not help. About the only solution I've found is to needle the 
> hammers excessively, but of course the tone is ruined then and out of balance 
> with the other hammers.
> 
> Only their Chinese customers find this to be a problem. They think the piano 
> is defective with these extraneous noises emanating only from 1 - 5 unisons 
> in the piano. I perceive the problem to be scaling oriented, but do not know 
> how to explain to the customer why it only occurs with certain unisons and 
> not others.
> 
> Has anybody found a good way to deal with or explain to the customer the 
> nature of  this problem? It has nothing to do with sympathetic vibrations, 
> the overtones are not pure, and they come from a single unison.
> 
> Waiting for your thoughtful reply.
> 
> Joel Swafford, RPT
>