The Core Sound Stealthy Cardioid microphones have a frequency response of
from 40 Hz to 18 kiloHertz. They have a slightly rising frequency
response over that range with the exception of a slight (2 dB) peak
between 9 kHz and 12 kiloHertz and a bass response fall off of roughly 6
dB per octave starting at 100 Hertz. (The bass response is very similar
to our Core Sound Binaural microphones' with the bass roll-off
filter).
We match the microphone pair to within one dB of each other. One of our
modifications alters the microphone's sensitivity to approximately -70
dB (0 dB = 1 Volt per microbar), making them ideally suited for
recording extremely loud sound sources without danger of overloading
your mic pre-amp. This very low sensitivity makes these mics less
suitable for recording quiet sound sources. The microphones have a
cardioid pickup pattern, rejecting sounds that are 90 degrees off-axis
by at least 6 dB and at 180 degrees by at least 20 dB (measured at 1
kHz).
Thanks to our modifications, the microphones have an undistorted dynamic
range of over 90 dB, compared to the unmodified capsules' approximately
60 dB dynamic range. They will handle sound pressure levels of more
than 138 dB. They are designed to operate into a nominal impedance of
between 4.7 and 10 KiloOhms. (If you need other impedances, please
contact us.) Their self-noise level is approximately 35 dBA. This is
far below the ambient noise level at concerts. (Note that the
self-noise specification also makes these mics not especially suitable
for recording very quiet sound sources.)
The Core Sound Stealthy Cardioid microphones require a bias voltage that
is supplied by its accompanying battery box, the same that is supplied
with Core Sound Binaural "battery box" microphones. Powered by a
standard 9 Volt alkaline transistor radio battery, the box also contains
associated electronics (top quality metallized polypropylene capacitors
hand matched to 1%, and 1% metal film resistors) and a high reliability,
US-made locking multi-pin connector. The battery box itself 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.
The output to the recorder is a mini stereo phone plug; other connectors
can be supplied upon request.
Next 
