We made a 48 minute tutorial video to accompany the audio workshop presented last weekend at Hackaday's SuperCon. Maybe it'll be of some interest here?
The video shows playing 2 wav files with software mixing, polyphonic sample playing, audio delay effects, filters, oscillators and ADSR envelopes, and continuous real-time peak & 1024 point FFT analysis.
Hope you like the video, and hopefully this message wasn't too spammy (full disclosure: I'm the creator of Teensy).
xl97:
(maybe the audio shield can be the same size as the teensy for v2?)
Connectors and mounting holes are the main issue to making such a small PCB. Assuming no mounting holes, where would the headphone jack and header for adding line in/out go?
I am working on another audio shield with a 2W amp chip for a single speaker, and some other nice features like APA102 LED driver (with proper SPI sharing). It'll be 1.9 by 0.7 inch.