Legal Notice:

SONOTRIM is a registered trademark of POSTHORN RECORDINGS. SONOTRIM is manufactured exclusively for and distributed worldwide by POSTHORN RECORDINGS.
So what is it, and why do I need one?

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 can 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 when positioning a lavalier. The SONOTRIM is small enough to be exposed where a larger microphone would have to be hidden, eliminating the risk of clothing rustle and muffled sound. In these important respects the SONOTRIM is indispensable to the working sound mixer or recordist.

Why does it look like a "Tram" but not sound like one?

Only the capsule is different – but vive la différence! The SONOTRIM is less nasal, more natural ; its 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. 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 professional standards. SONOTRIMs can be identified by their serial number, which starts with an "S." The cable has a white shrink-tube at the connector, and an exposed metallic “iris” at its sound inlet. Otherwise, their battery supplies (if of the same bias!) and accessories are the same, except for Sonotrim's added BLTD boundary-layer adapter and a reinforced Tie Bar with cable guide.

Doesn't it cost more?

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

How is it powered?

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 do remove the battery first!). However, please do note: a SONOTRIM, wired for positive bias, if connected to a polarity-inverting wireless link, may be "out-of-phase" when mixed with other microphones. A "phase-reverse" cable or adapter is needed at the receiver's output to correct any possible phase anomalies. When the STR-79 battery supply is used, the SONOTRIM's polarity will be inverted and it will be “in phase” with other microphones.

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 Kevlar-reinforced two-conductor shielded cable makes the choice of either positive or negative bias a simple wiring preference.

Now I suppose I should choose a color . . .

SONOTRIMs are available in black, gray, white or tan ("flesh"), with cable and mounting accessories in matching colors. When ordering, prefix the letters B-, G-, W-, or T- to the microphone you are ordering, or any additional accessories you are selecting.


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Most recent revision January 1, 2015