6v6gt:
Do you have to decode the signal at all ? Would it not be possible to handle it as a pure audio signal and store and retrieve it from such a device: SparkFun MP3 Player Shield - DEV-12660 - SparkFun Electronics
The arduino would then interpret commands from the synthesizer (fast forward, rewind, play etc.) and deliver plausible responses.
My understanding is that device is just a MP3 decoder. It does not have any encoding ability. You could playback encoded streams, but I am unsure how the loosy compression would distort the data?
Chuck.