Voicing

Hello.

Does anyone have any idea why some bass string create a high pitched noise when struck by the hammer? It has occurred on all makes of piano, monochord and bichord strings. Usually it's just one note, all the rest are fine. I've thought that it could be the plate resonating in some way.  I also thought maybe it's the string design, perhaps too heavy of a string for the note it produces, like striking steel pipe.

I could describe it as a high pitched "dog bark".  Sometimes faint, sometimes really loud where it drowns out the fundamental for a second after being struck by the hammer.

I've asked around at conventions and no one quite understands what I mean. 

Thanks very much.
Robert

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Robert Callaghan
Reno NV
775-287-2140
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Callaghan: "Does anyone have any idea why some bass string create a high pitched noise when struck by the hammer?"

Here is a link to Five Lectures on the Acoustics of the Piano. It includes the sound samples.

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Fred Sturm
fssturm@unm.edu
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Ellis's patent is 5,874,685  dated February 23, 1999. 
Here is main US patent site 
http://www.uspto.gov/patents/process/search/

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David Skolnik
Hastings-on-Hudson NY
914-231-7565
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Original Message:
Sent: 07-07-2011 21:39
From: Fred Sturm
Subject: non-musical resonance in bass string

Callaghan: "Does anyone have any idea why some bass string create a high pitched noise when struck by the hammer?"

Could be longitudinal modes in action. See Jim Ellis' articles in the PTJ (and book). Also Conklin's article in five lectures on the acoustics of the piano (I seem to remember hearing it was posted on the web somewhere). There was an audio file with the book that demonstrated them pretty clearly.

Essentially, it is the string vibrating "back and forth" lengthwise, in line with the length of the string, as opposed to the principle form of vibration which is essentially at right angles to the length of the string. The pitches of longitudinal modes are fairly high pitched, and often "inharmonic" (way out of phase with the tuning). String makers like Jim Arledge account for this in designing strings. Jim Ellis patented some method of calculation that he licensed to Charles Walter.

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Fred Sturm
fssturm@unm.edu
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"Ellis's patent is 5,874,685  dated February 23, 1999."
It is far easier to access patents at www.google.com/patents than at the US patent office web site. Much better search engine, faster.


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Fred Sturm
University of New Mexico
fssturm@unm.edu
"The true sign of intelligence is not knowledge, but imagination." - Einstein
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