Why is D unpopular?

[Guillaume Piolat]

On Sunday, 1 May 2022 at 19:02:41 UTC, Ola Fosheim Grøstad wrote:
> You also have the issue of tracking pitch correctly, which I 
> believe is where Autotune cut costs by doing pitch tracking by 
> autocorrelation more cheaply. That is a technical improvement, 
> not a conceptual one.

There is indeed a 1999 technique by Autotune makers that did 
track pitch with a kind of "sliding auto-correlation" (you would 
slide spectrally but instead of computing a single DFT 
coefficient, you compte a correlation coefficient), I believe 
this is maybe the technique that was famously imported from 
seismic detection.