[ntp:questions] Using NTP to calibrate sound app

unruh unruh at invalid.ca
Wed Jan 30 07:06:04 UTC 2013


On 2013-01-30, A C <agcarver+ntp at acarver.net> wrote:
> On 1/29/2013 12:04, unruh wrote:
>
>> Actually for a piano, there is ALWAYS beating. The three strings have
>> three modes, and it is impossible to tune all those three modes to the
>> same frequency, because the soundboard couples them. Thus the three
>> modes all sound to gether with slightly different frequencies. This is
>> part of what gives the piano its distinctive sound over say a
>> harpsichord.
>
> The piano tuners that I have met have been tuning professionally for 
> decades.  They always clamp and damp two of the three strings (on the 
> upper half of the keyboard, the bass notes only have two strings or 
> fewer) and tune each string independent of the others.  The strings from 
> adjacent notes and further along the soundboard will vibrate, too, but 
> not as sympathetically as the other strings struck by the same hammer.

Yes. Unfortunately when you release those other two  strings, the
frequency
of the combined strings is not the same as the frequencies of the
strings individually. The late time, decayed note is close to that
single string tuned note (slightly higher), but the earlier sound is
lower.



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