Schoeps CMC621NI-ST

The CMC621 ST microphone package that includes 2 CMC 6 amplifiers with MK 21 wide cardioids, A20 suspensions, and B5 popscreens. Available in a nickel finish.

The chief task of a CMC microphone amplifier is to convert the extremely high-impedance signal from the capsule to a very low-impedance one suitable for transmission through a microphone cable. It features a symmetrical class-A output stage with neither coupling condensers nor an output transformer. This design helps it to achieve extremely low distortion and light physical weight, while its very low output impedance helps make it insensitive to electrical interference. The CMC 6 works with both 12 V and 48 V phantom powering so long as the relevant standard is followed. In addition to the CMC 6's dual-voltage circuitry, the two amplifiers differ in their response at the very bottom of the audio frequency range. The CMC 6 is essentially flat to 20 Hz.

The MK21 capsule has a directional pattern between omni and cardioid. The basic idea in designing this capsule was to combine the advantages of the cardioid with those of the omni. This results in a pickup pattern which blends the two sets of characteristics in a useful manner. It has fuller and more extended low-frequency response than a cardioid, with less proximity effect, while attenuating side- and rear-incident sound less than a cardioid. The polar diagram shows it to be only slightly dependent on frequency. This contrasts with omnidirectional microphones, whose directivity increases with rising frequency, and with cardioids (at least smaller ones), which tend to accentuate high frequencies that arrive at oblique angles. The MK 21 orientation is less critical than with a cardioid, since direct sound arriving on axis and reverberant or other sounds off axis are both reproduced accurately. This lack of coloration in the off-axis pickup produces a “warm” and natural sound image. When used as a spot microphone it must be placed somewhat closer to the sound source than a cardioid would be, due to its lower directivity. Its uniform off-axis response helps to blend nearby instruments seamlessly into the overall mix. For wide pickups where some directivity of the microphone is advantageous, as in acoustically difficult rooms where the bass would be too strong when using omnis, the MK 21 can be especially helpful. The low directivity of this microphone type prevents it from generating large enough level differences for X/Y use, though M/S and near-coincident spacings are often successful.