[magicalhippo]

Sure, but having a channel with 25% duty cycle of frequency f and a channel with 75% duty cycle of frequency 3f will lead to a different waveform after mixing compared to 75% at f and 25% at 3f, no?

Depending on how that's processed downstream it could sound very different I imagine.

In crude ASCII art (two inputs mixed to an output):

  ---_________
  
  ---_---_---_
  
  
  ¨¨¨_---_---_

vs

  --------____
  
  -___-___-___
  
  
  ¨---¨----___

[recursive]

I saw a video a few years that provided pretty convincing experimental evidence that's not actually the case.

https://www.youtube.com/watch?v=Ffka-hPzug0

[magicalhippo]

Very interesting, though any non-linear effects would definitely get affected.

Not sure how much that comes into play on the Gameboy though.