frequency vs throttle graphing is rather difficult

[nerdCopter]

This was not easy whatsoever, and still does not mimic the BBE spectrums that are easy for human analysis.
A.I. tells me this is ultra correct, but for me the black bands and the lack of discernible noise path is questionable.

this is branch 20250516_try_spectrograph_again at commit 305398e.

Reference the STELLARH7DEV graph directly above (last) and compare to BBE:

other output examples