Hi,
I've just published an Audio library, similar to the official AudioZero lib, but non blocking : you can do other stuff while the sound is playing.
It should work with 8bit mono wav file from an SD card. My setup don't let me try it with a sample rate of more than 22.050KHz, because I already have audible noise on my custom Zero board.
If someone would like to try it on his board and tell me what is the max sample rate, I'd apreciate that!
here is the link : GitHub - AloyseTech/Zerodio: Non blocking audio library for Arduino Zero
You have to use an external amplifier connected to the DAC at one side, and speaker or headphones at the output. See here : https://www.arduino.cc/en/Tutorial/SimpleAudioPlayerZero