> I found that with the little encased piezo speaker I have that
> if I feed it a pulse with a 33% duty cycle I get a better sound
> than if I use 50%

Just a guess - I mentioned that the piezos are quite capacitive.
Could it be that the 50% square wave (presumably still directly
from the PIC) is being integrated by the piezo ? That is, the
spaces between the pulses is being filled in somewhat and so
the effective M:S ratio is higher than 50%. At 33% the gaps
between are obviously wider. Sounds like a job for your new
scope eh ? - find out the quality of the wave

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