[pclmulqdq]

Sure, related to tuning because it's a pretty closed problem. The expertise in terms of tuning was developed over about ~800 years, but the math for modern tuning was known 500 years ago. It's conceivable that one could re-invent equal temperament and then quickly re-invent the modern tuner given everything we know about electronics and audio processing. However, that knowledge all builds on itself. If we decide that all audio processing is done with RNNs/ML instead of objective ("old") mathematics, then we're going to lose the ability to make a tuner, too, and eventually we'll need a new Fourier to come back up with the Fourier transform.

About the tomatoes in the other comment chain? Your guess is as good as mine whether we can recover that knowledge.

[nyanpasu64]

I heard that pianos have stretched harmonic series due to string tension/weight/something, so piano tuners actually have to tune upper notes higher and lower notes lower, while ensuring various harmonics interact well. There's quite a bit of art to it rather than pure numeric ratios (which may or may not be possible to encapsulate in ML).

[pclmulqdq]

Yes, this is correct for pianos. I believe it is actually due to the thickness of the strings varying a lot across the instrument.

Most piano tuners today use a tuner for a middle octave and then tune the outer octaves by ear.