The SONOTRIM is a high-quality electret microphone whose low profile and broad range of accessories make it ideal for "body" or "stashed" placement. It readily interfaces with all popular wireless systems, or it may be battery-powered. It is distinguished from "look-alikes" by its more "open" sound, thanks to a special transducer of a broadband, low-distortion, low-noise design. A hint of high-frequency emphasis improves speech intelligibility and helps to offset the inevitable compromises in placement. 

Only the capsule is different – but vive la différence! The SONOTRIM’s less nasal, more natural sound mixes surprisingly well with a good boom mike to achieve a combination of presence and ambience well suited to today’s film and video projects. The flatter high-frequency response of the SONOTRIM reduces the raw, gritty "edge" produced by the HF peak in some microphones, which interacts with the transmitter’s pre-emphasis network to create distortion at even moderate levels. Also, the SONOTRIM can be reversed in its mount to reduce wind and clothing noise without altering its sound (the Tram gets "peakier" when turned to face inward). Finally, the SONOTRIM’s quality control is tighter, as each unit is individually measured and auditioned to meet rigid standards. Otherwise, their battery supplies (if the same bias!) and accessories are interchangeable.

Better things often do. Besides, the price includes the Boundary Layer Tape-Down clip as an extra, tucked into a blue snap-clasp carrying case along with the usual Tie Tac, Tape-Down tab, Cable Holder, Windscreen and Clip-On Holder ("Vampire clip"). When the microphone must be hidden under clothing (despite the risk of rubbing noise and muffled sound), the  optional Microphone Cage accessories can be a real help. The plain back MC-1 uses double-stick tape; the MC-2 is backed by a "Vampire clip."

The SONOTRIM can be powered by any of the popular wireless transmitters or by its own STR-79 battery supply, which is also useful as a standby in the event of RF problems. Battery life, depending on cell type, is 4000–20,000 hours. The hardwired STR-PS model will work with 12V–48V phantom power, as will the positive-bias battery supplies (but doremove the battery first!). PLEASE NOTE: SONOTRIMs wired for positive bias, if powered by a wireless transmitter, may be "out-of-phase" when mixed with other microphones. To prevent any risk of cancellation, use a "phase-reverse" cable or adapter at the receiver's output. When powered by the STR-79 battery supply, however, the microphone's polarity is inverted to be "in phase" with the others.

What's this about positive and negative bias?

Older RF transmitter designs which powered electret microphones were usually wired for negative bias. Newer designs either offer both bias options or are positive-bias only. In wireless applications, given the rather arbitrary notion of "ground," the choice makes little difference. However, when the microphone with its battery supply is connected to conventionally grounded equipment, positive bias is definitely preferred. Negative bias leaves the microphone element ungrounded, vulnerable to the hums and buzzes generated by SCRs in lighting boards and the manifold sources of EMI and RFI that inhabit most recording environments. The SONOTRIM’s two-conductor shielded cable allows the capsule to be wired for either positive or negative bias.

SONOTRIMs normally are Black or Gray. For an extra $25, they can be White or Tan ("flesh"), with matching cable and mounting accessories. When ordering, prefix the letters B, G, W, or T to the microphone or any additional accessories you have selected.