2. Nothing worked until I formatted the SD card with SDFormatter. No idea why - this blew my mind. See Dr_Ugi's post about it: http://www.instructables.com/id/Handheld-Pong-Invaders-on-the-Cheap-Arduino-Compat/step6/Prep-Set-up-the-Sound-Module-and-SD-Card/3. I found a way to export directly from Audacity with the following settings:Mono file Project Rate 16000 Hz (lower left corner)File > Export Audio...File type: Other uncompressed filesFormat optionsHeader: WAV (Microsoft)Encoding: Unsigned 8-Bit PCMSave your file as 0###.wav where ### is 000 to 511 What do you mean exactly by "I found a way to export directly from Audacity"? What is the background of your finding?
I still have some annoying noise when the sound files start to play for a few seconds and a chopper like noise in the background all the time.
The solution:The solution is to connect a wire from Pin6 of the SD Card socket to Pin 8 (GND) of the sound module. As I said I cannot take credit for discovering this. See this post showing the wire that was added.