Well-known German audio electronics company Sennheiser develops two audio modules called Amphion and Proteus
According to online magazine Modular Phones Forum:
"The Amphion module is equipped with a noise-canceling microphone and an amplifier that can record and play your music with unprecedented force and admirable clarity. The module also contains a low latency digital processor to take advantage of Sennheiser’s digital playback experience. On top of that, by opening up hardware Sennheiser wants to make DSP (Digital Signal Processor) user-programmable.""The Proteus module contains two audio jacks for two headphones. The underlining idea is to allow a user to effortlessly share their music with a friend and listen to music without causing any external disturbance. The module also could become a tool to do other interesting things, such as connecting up to four microphones to create a super-directive audio capture."