HiFiBerry 

Sound processing and music production

HiFiBerry products cannot only be used for music playback, but also music production. Projects like Zynthian use HiFiBerry sound cards to sample, process and output the modified audio data. With Zynthian, you can use your HiFiBerry-based system as a Synthesizer or as a very advanced effects processor.

Other projects use the Digi+ I/O as a digital audio interface to process audio. If you just want to implement some audio processing that should run independent from the software running on the Pi, check out the HiFiBerry DSP sound cards.