ive started my sound system and have a simple engine simulation running (can be heard here ). at the moment its using 2 samples 1 for idle and 1 for high revs, but i think it will sound better with 3 samples.

im having trouble figuring out the maths to make sample 1 get quieter as the revs increase (2500 + ), sample 2 gets louder towards middle revs (lets say 5000) and quieter as it goes past those revs as sample 3 gets louder as it gets to full revs (10,000)

anyone understand?