Variable duty cycle square waves with the Web Audio API

Re:Variable duty cycle square waves with the Web Audio API by recursive on Monday April 07, 2025 @02:22PM (#43614387)

Adding more channels does nothing to the overtone information. From what I can find[1], it seems that the phase of the 25% and 75% waves are such that the two waves are actually inverse of each other. I don't know much about Gameboy hardware though. Do you actually know what the point of this is?

[1]: https://gbdev.gg8.se/wiki/articles/Gameboy_sound_hardware#Sq...

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Re:Variable duty cycle square waves with the Web Audio API by magicalhippo on Monday April 07, 2025 @07:09PM (#43616897)

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):

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

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

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Re:Variable duty cycle square waves with the Web Audio API by recursive on Monday April 07, 2025 @07:20PM (#43616939)

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

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Re:Variable duty cycle square waves with the Web Audio API by magicalhippo on Monday April 07, 2025 @10:06PM (#43617704)

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

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

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Re:Variable duty cycle square waves with the Web Audio API by charcircuit on Monday April 07, 2025 @09:29PM (#43617545)

If you play 2 inverse waves it will sound different than 2 of the same wave.

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