[Plib-devel] OT: engine sound synthesis

[Bram S. <br...@sa...>]

Hello plibbers,


Sorry for the off-topic mail, but I want to pick the brains on this list.

I am trying to generate good quality engine sounds.

After thinking about this, I think that the parameterization of the
engine sound comes down to:
- throttle parameter (open throttle means more sound)
- rpm parameter (higher rpm means 'different' sound).

My first approach failed miserably:
- Completely synthetic solution:
  Generate explosions (white noise with degrading freq's), and
  separate them in time, based on RPM.
This sounds way too synthetic, and not like a real engine.

My second (naive) approach gives bad results as well:
- sampled the engine noise of my chevy small block at idle (1000rpm)
- throttle modulates amplitude
- rpm dictates play-back frequency.
  (at 2000 game RPMs, I skip every other sample from the real life 1000 rpm
   clip).

Isn't there a method that can change playback rates of soundclips without
changing the frequencies on the sound? What is this technique called? And
can it be done in real time? Is it applicable for engine sound synthesis?

Thanks in advance,

  Bram Stolk

PS: I'm not using plib's sl here, because I'm on ALSA, not op OSS.