Testing microphone performance for Codec 2

Codec 2 is the open source and patent-free voice codec used in FreeDV, a digital voice mode used in amateur radio. Since Codec 2 is designed to be used at very low bitrates (the current version of FreeDV uses 1300bps and 700bps), it does an adequate job at encoding voice, but can't encode well other types of sounds, and thus fails poorly in the presence of noise. Hence, microphones which may be good enough for other applications can give poor results when used for FreeDV (if, for instance, they pick up too much ambient noise or have too much echo). This is a small note about how to test the microphone performance for Codec 2.

Continue reading "Testing microphone performance for Codec 2"