There seems (I hope I'm wrong) to be a design issue with the square wave generator in relation to the sawtooth wave generator. Sorry if this is a bit technical, I'd really appreciate input from the engineers on this one.
I've noticed that when the Saw is all the way up and I bring up the square wave (at 50% duty cycle), eventually, when both are up, I don't hear the square wave anymore.
I haven't checked with a scope, but what I'm suspecting is the following:
When adding both waves, if at phase 0º the saw is starting from -1 and ramping up to +1 at 360º and the square starts at 1 until 180º where it will go to -1 until 360º, then, instead of the expect addition of harmonics, the result is a sawtooth wave that is phase-shifted by 180º. That phase shifted sawtooth wave sounds exactly like the sawtooth alone.
What should be done is the square wave's phase should be inverted so that from 0º to 180º, the value is -1 and 1 from 180º to 360º.
If you don't understand the two last paragraphs, take some graphing paper. Draw a sawtooth and a square. Add them. Then, do the same but with the square wave inverted. You will immediately see what I mean.
Can someone confirm if this is the case, and if so, is there a hardware fix that can be done to invert the square wave's phase?
[EDIT. I added an image for clarity]