Sound effect mixing with OpenSL on Android

This is probably not the best approach (creating many instances of audio players). Unfortunately the Android version (2.3) of OpenSL ES doesn't support SLDynamicSourceItf. Which would be similar to OpenAL's source binding interface. One approach would be to create multiple stream players. You would then search for a stream player that isn't currently playing and start streaming your sound effect to it from memory. It's not ideal but it's doable.

You should probably not use the ogg format for sound effects either. You're better off with WAV (PCM) as it won't need to be decoded.

Ogg is fine for streaming background music.