Compression waves

[Ron Nossaman]

>I am taking as given that the compression wave is significant in the 
>tone building of a piano string, though I am not at all convinced of 
>this and Conklin's paper does not provide adequate data to enable me 
>to verify his findings.  What the relative strength is of the sounds 
>induced by the compression wave is the key point, since if they are 
>so weak as to be virtually inaudible, then the whole book goes out of 
>the window.
>
>In his paper he states:
>
>>In longitudinal modes of vibration, energy propagates lengthwise 
>>along the string (as periodic compressions of the string material) 
>>without sidewise (transverse) motion of the string. Longitudinal and 
>>transverse vibrations of a piano string can occur simultaneously. 
>>However, the lowest-frequency longitudinal mode of a piano string is 
>>always more than ten times the frequency of the lowest-frequency 
>>transverse mode.
>
>My tests this morning suggest that this is miles from the facts and 
>that it would be a meaningless comparison even if it were close. 
>Bear in mind that this extract is in the context of his treatment of 
>covered strings.

You might also bear in mind that his statement about the longitudinal mode
frequencies being at least ten times that of the fundamental transverse
frequency relates to plain wire strings, as does his rough formula of
2500/L that I posted earlier. He says that wrapping the core lowers the LM1
(longitudinal mode fundamental) significantly and reasonably predictably.
That whistle in the LM of the core you tested was it, and that is the
significant frequency relationship for everything that isn't wrapped. That
would be essentially every string with supposed tuned front and rear
duplexes, unless you have seen these features connected to wrapped strings. 

Meanwhile, go to http://www.uspto.gov/patft/ and look up patent# 3,523,480.
Print it out and find your magnifying glass. Also try to get a copy of
"Design and tone in the mechanistic piano. Part III. Piano strings and
scale design" as was published in the Journal of the Acoustical Society of
America in 1996. 


Ron N