I'm trying to understand a patch/abstraction in Max for Live called M4L.bal1, but I think the question is a pretty general one about digital audio processing.
The patch mixes two audio signals according to an adjustable parameter P ranging from 0 to 1; so that P=0 corresponds to 100% signal 1 and P=1 to 100% signal 2.
Naively I would expect you can multiply signal 1 with 1-P and signal 2 with P and then add them together. But the patch does something quite different:
The patch multiplies both signals with cosine waves (the frequency of which are not specified, I assume it's a default value) and then added together. The cosines have the same frequencies but different phases; the actual phases depend on P and range from 0 to 0.25 while the difference between the cosine phases is equal to 0.75 independent of P. I assume the phases are given in units of pi radians.
I'd be grateful if anyone could explain how this accomplishes mixing the signals!
Here's a picture of the patch: