You have to put the actual frequency, not a flag, i.e. 44100, 48000..etc...Of course it works fine for MP3s...Stream files do not use this frequency, they use the one they are encoded at. Music files (MODs, MO3, XM, IT...etc) are the only ones that use this frequency. If you put the flag WAVE_FORMAT_4S16, you are making the frequency the value of that flag, which is a very small number.