What’s inside a Beyerdynamic M260?

This is what happens when one dissects a couple of Beyerdynamic ribbon mics: bodies, grills, motors, transformers, XLR or DIN output connectors. Nothing surprising there….

But what are those grey plastic tubes?

These are in fact acoustic chambers that provide back pressure to the ribbon, changing it from its natural figure-8 pattern towards being hyper-cardioid. It is also critical to the microphone’s sound – if you make an M260 without one, it sounds pretty awful.
There is one more important ingredient to the mic, and that is a piece of string. This is stuffed into the chamber to break up internal reflections. Sometimes simple works!