AKG C451 B Small Diaphragm Condenser Microphone Matched Pair. This matched pair of C451 B ST Small-Diaphragm Condenser Microphones from AKG is well suited to record drums, percussions, acoustic guitars and strings in the studio and in live situations. It is engineered to approximate the sound of its predecessor, the C451 EB + CK1, but with its redesigned hand-crafted fixed capsule (which eliminates the mechanical problems associated with the original modular design), and its low-noise preamp electronics, this microphone delivers accurate transients for a bright and detailed sound.