I don't particularly care for the KH1's sidetone for two reasons:
First of all, it sounds terrible and I find it to be reminiscent of a code practice oscillator I built as a kid.
Second, there is no way to zero-beat a station based on how their pitch relates to your own sidetone.
Neither of these reasons matter too much - the KH1 is a utilitarian radio designed for a specific purpose - quick deployment in scenarios where other stations are doing the calling (and therefore the zero-beating).
But I wondered: What exactly are the audio components that produce the KH1's sidetone? Nothing in the KH1's manual gives any indication of how the sidetone is generated.
Spectroid to the rescue!
For comparison, here is my Elecraft KX2, with its sidetone set for 560 Hz:
And here is the KH1's sidetone, comprised of many discreet frequencies between 1000 and 11,000 Hz:
UPDATE (20 Nov):
Wayne N6KR mentions on the KX Group.io that I must have taken the reading in "SPOT" mode which would include a bit of background (receive) audio in the spectrum plot. So I made another measurement - key-down - not spot.
Here is the plot for the sidetone (and only the sidetone).
Again, the KH1 sidetone is a broad-spcetrum audio signal consisting of tones from 1000 to 11,000 Hz (thus the raspy sound):
Anyone with a KH1 can verify this via one of the many audio spectrum apps available for smartphones.