The Piano Sound Is A Moving Target

The piano sound is never in a steady state of settled frequency, hence, a ‘moving target.’ “When, in time, do we set the tuning, and on what basis?” This phenomenon is not universally understood, nor agreed upon. We are left with many subjective methods, many diametrically opposed.
Solution:
Make ‘new technology’ to show in real time how the partials of a given string are changing frequency over time, giving the piano technician a ’target in time’ that is consistent and repeatable.
Make this a more objective practice, raising the bar to a higher level in the piano tuning industry.

[@rickclark1372]

This is outstanding work. The most comprehensive objectively measured description of what is happening with pitch following the note strike that has ever been published/reported I believe.

[@8891randy]

You have to watch this several times. It’s the best explanation of why we need to tune unisons as perfectly as possible- how it affects the tone. The second example in the video has a sound that would make me think the string wasn’t seated properly or the hammer needs to be filed. But that’s not it - it’s the response of the partials behaving from the result of a less than perfect unison. The kind of unison you would get when tuning by ear.

[@lingerlights]

Interesting

[@barrybraksick5504]

Hi Steven, saw your pianoworld post. Very interesting comparison. There is a technique called the "phase vocoder" that builds on the STFT which can produce the kind of frequency and amplitude analysis you're talking about here. I first encountered it many ears ago in the book "Digital Audio Signal Processing: An Anthology" by John Strawn, but I'm sure there are other explainers online now.

[@PianoSens-ey8jb]

I am familiar with the phase vocoder. I use a different approach to get ultra fine grain frequency estimate between FFT bins that is better in this application. Thanks for the reference.