My *.wav's work as expected. But wav files are to big, so I want to play *.mp3 or *.ogg but it doesn't work.

I use this lines of code found in the finch Demo project

engine = [[Finch alloc] init];
sitar = [[Sound alloc] initWithFile:RSRC(@"sitar.wav")];
[sitar play];

So I only change sitar.wav into my .mp3 filename.

Note 1: It mustn't be mp3 or ogg, any file format not as huge as wav should be ok, but which ?

Note 2: I didn't know how to use sound, so I searched and found finch here at stackoverflow. It looks easy, so I would like to use that, but if you know some other easy way to play that sound files (ambient + effects sound with compressed codec) I would also switch to that other technique.