For installations in which 48-Volt powering will always be provided and in which RFI is not an issue, the model CMC 5 Ug is available.

Variant Amplifier Versions
Special versions of the CMC 5 Ug are available with different gain (amplification factor) or extended low-frequency range. Either type of amplifier can be specially ordered, or retrofitted at the factory, to have a different low-frequency limit from the standard version (see, for example, the ”linear” version listed below).

Please note:
The two amplifiers in a stereo pair of microphones should be of the same type.

CMC 5 Ug linear
The CMC 5 Ug microphone amplifier normally has a gradual rolloff in response below 30 Hz to guard against infrasonic disturbances from various sources such as air movement and vibration. However, when using pressure (omnidirectional) transducers, particularly with digital recording, it can be desirable to pick up frequencies below 20 Hz without attenuation. The special technology of the CMC 5 Ug linear microphone amplifiers makes this possible; on request we can deliver microphone amplifiers with response that is flat to as low as 3 Hz.

Caution must be advised with respect to infrasonics, however. Since pressure transducers can pick up very low frequencies, ventilation systems in large spaces (churches, concert halls) or traffic rumble can create a problem. With pressure gradient transducers the risk is even greater. They are far less sensitive to very low frequency sound, but respond much more strongly to low-frequency mechanical stimuli such as air currents and solid-borne noise. Such signals may be below the audible range of frequencies, but they can overload electronic circuitry and produce severe distortion, particularly in transformer-coupled circuitry.

CMC 5 Ug +5 dB
The sensitivity of a microphone using this type of amplifier is 5 dB higher than with the standard version, but the equivalent noise level and maximum output voltage are not materially affected. Thus the highest sound pressure level which the microphone can accept without distortion is 5 dB lower than in the standard version, while the signal-to-noise ratio is essentially the same with either gain setting.
This version might be chosen in order to raise the microphone's signals above the noise level of the equipment to which it will be connected, and / or for working with sounds that occur mainly at low levels.

User guide