Sorry if I post this here, but I didn''t find any other resources. How do I manage to modify and alter sounds ? I mean for example an engine, with his relative .wav file: when I give some gas, how do I change the sound to increase volume and other carachteristics of the .wav file ? Thanks !

Look in the documentation for your API.

do you mean the directsound API''s ?

Direct Sound Data Manipulation... that''s indeed a difficult subject... I''m still not totally familiar with this - although I did pretty much of research...
If you really want to know what you do there, you should go and read some physics books about sonic interpolation and anything regarding this topic (your public library ought to have such books)
But to be honest, I think that this would be a bit too much, so I recommend you to search for some free module player source.
They manipulate each sample''s sound data when playing the tunes in different frequencies. I do not remember where to get these sources though, have a look at the Music&Audio Board, there''s an older post with some links.

Hope this helps
pi~

Yes, look in the documentation for DirectSound if you are using it.