G'day all, long-time lurker trying to get back into the basics of PICs...

A question on whether theory would translate into practice; I'm looking at
a project that has stereo sound output via two PWM channels with RC
filters on the end.  Now, I'm only going to be driving a single speaker,
but want to keep the two sound streams and merge them.
I've physically tested combining the analogue out of the two RC filters,
and also combining the "digital" outputs of the two PWMs before going into
ONE RC filter; my theory now is, can I get the numbers that are driving
the two PWMs and simply add them together, to drive one PWM, and still
result in the same sound?  To my mind in theory it should work, as this is
essentially what is happening when you physically connect the two PWM
outputs together, or am I missing something?

Actually, I just had a thought; maybe I need to take the _maximum_ of the
two figures, ie. if channel1 has a 10% duty cycle and channel2 has a 15%
duty cycle, the physical combination of the two would be 15%, not 10+15 =
25%?  Only the _amplitude_ of the square wave would increase where the 10
& 15 overlap, not the duration... ?
Obviously there will be a difference in volume between the physical mixing
method and the code mixing, but I'll be using an amplifier anyway, and
need to keep external components to a minimum.  Also want to free up the
other PWM channel for another purpose.

Thoughts?

Thanks
Lee
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