For Linux systems that can't handle multiple audio streams (e.g. Debian Wheezy 7.7 with stock ALSA install using an external sound card configured in .asoundrc) it is not possible to instantiate more than one MediaPlayer as they hold on to the audio device throughout their life cycle.

It would be nice if the MediaPlayer only claimed the audio device when it actually attempted to play the file, or it it could be told programmatically to release/claim the device.

Apparently dmix can be configured for such cards, but it is difficult and dependent on end-users.