Refers to the size of the diaphragm used in a microphone. The definition of Medium Diaphragm is a potentially controversial subject. Historically there have been large diaphragm and small diaphragm mics, but more recently the medium size has began to carve out its own category, though not everyone agrees on the precise upper and lower limits. Most professionals and manufacturers agree that any microphone with a diaphragm near 5/8″ to 3/4″ can be characterized as a Medium Diaphragm microphone. Generally speaking, Medium Diaphragm microphones tend to do a decent job of accurately catching transients and high frequency content (as a small diaphragm would) while delivering a slightly fuller, round and potentially warmer sound (as a large diaphragm might).