Matched pair of C 451 B The matched pairs consist of two microphones that are within 1 dB to each other in sensitivity and also within 1 dB to each other in the range of 200 Hz to 15,000 Hz of the individual frequency response when used in cardioid mode and are selected from a large quantity of individual microphones using the described criteria by using a proprietary computer program. Using this matched pair for stereo recordings utilizing various techniques will provide for a good and stable balance without frequency-dependent shifting of the stereo panorama. The kit includes all the standard accessories of the individual package along with a stereo bar and proof of performance charts in an attractive carrying case (Soundtool case, middle size).