Roger Halstead wrote:

Ideally a muffler could combine pulses into a steady string and
average them out. The higher the RPM and the more cylinders the
higher the frequency. The larger the pulse volume the more difficult
to smooth, The higher the frequency the easier to smooth.

Agreed.

Playing with a bit of math and an over simplification where I always
make at least one mistake:

I'm not particularly "challenged" in any way, but frankly, I don't
understand the point of your calculations. But the principle is simple
and I agree: The bigger the volume of one (!) pulse, the bigger the
volume of the muffler. Everything beyond this pronciple is beyond me,
too, and left to the specialized engineers. All I know is that I can
hear the difference between a good and a bad muffler.

Stefan