Core Sound — Core Sound Binaural microphone set

The CSB microphone sets are based on a pair of Matsushita (Panasonic) miniature omnidirectional electret condensor cartridges. They are electrically and mechanically modified to provide a more linear sound-to-voltage transfer function and to eliminate mechanical resonances in their bass response. The modifications add more than 20 dB to the microphones' undistorted dynamic range, flatten and extend their low frequency response, and all but eliminate recorder overload distortion.

Before Core Sound's modifications, the Matsushita cartridge's frequency response is specified flat within 1 dB from less than 40 Hertz to more than 15 kiloHertz. Typically they are within 1 dB up to 20 kiloHertz and down less than 5 dB at 30 Hertz. After modification, the modified cartridges sound better than that, typically within 1 dB from 20 to 20,000 Hertz. We match the pair to within one dB of each other. Sensitivity of the modified cartridges is approximately -66 dB (0 dB = 1 Volt per microbar). The microphones are nominally omnidirectional but their pickup pattern is modified by the absorption and reflection characteristics of your head and outer ears. Their noise level is typical of 1/4-inch electret condensor microphones, approximately 30 dBA. This is comfortably below the noise level of the Sony DAT and MD recorders' microphone pre-amplifiers and the ambient noise level at concerts. Thanks to our modifications, the CS Binaural mic set has a dynamic range of over 90 dB. They are designed to operate into a nominal impedance of 10 KiloOhms.

The CSBs provide the highest sound quality (e.g., when using a DAT recorder), and very low distortion operation at the high sound pressure levels typical of rock concerts and even high performance racing motorcycles (from 110 db to 140 dB SPL). In addition to the two matched microphones, the CSBs come with a battery box containing a nine volt battery, associated electronics (top quality metallized polypropylene capacitors hand matched to 1%, and 1% metal film resistors) and a high reliability, locking multi-pin connector. Use of the battery box allows us to modify the microphone cartridges for much improved linearity (less distortion) and expanded dynamic range. The battery box is not a pre-amp; it simply provides the correct voltage to power the mics and also houses the optional bass roll-off filter.

The battery box is roughly half the size of a cigarette pack, is made of sturdy die cast aluminum, and is finished in a durable black crinkle finish. The battery lasts approximately 500 hours and should be replaced at least once a year. (Be sure to disconnect the microphones from the battery box when they are not in use.) The output to the recorder is a mini stereo phone plug; other connectors can be supplied upon request.