AKG CBL201B Boundary Layer Mic

A boundary-layer microphone mounts flush against a flat surface and uses that surface as part of its pickup, which reduces the hollow sound you get when direct and reflected audio arrive at a capsule at different times. The CBL201B differs from most boundary mics by carrying two cardioid elements instead of one, arranged 180° apart to cover both sides of a table from a single unit.

The CBL201B uses a cardioid polar pattern on each of its two elements. Cardioid pickup is strongest in front of the capsule and rejects sound from behind, which helps keep HVAC noise, projector fans, and room reflections out of the mix. With the two elements set 180° apart, the combined coverage spans the length of a table rather than a single seat.

The CBL201B runs on 24V to 48V phantom power supplied by your mixer, DSP, or mic preamp. No external power supply is required. Typical current draw is 500 µA per mic, with a maximum of 600 µA, so a standard conferencing DSP can feed several units on one card.

You can set the mic on the table surface for a temporary setup, or mount it permanently by drilling the tabletop and running the included threaded rod through the hole, then securing it underneath with the wingnut. The included end seal and table seal finish the opening, and screw terminals on the underside handle both the mic wiring and the logic I/O. Permanent mounting is the better option for rooms where the mic placement should not move.

No. The touch pad sends a logic output signal, and the LED ring responds to a logic input, so your DSP or control system performs the actual mute and drives the indicator color. Plan for a control processor or a conferencing DSP with logic ports if you want the mute button and LED to work as intended.

The CBL201 carries two cardioid elements in a 180° layout, and the CBL301 carries three elements for wider coverage around the unit. Both share the same low-profile housing, touch controls, LED ring, and phantom power requirements. Pick the CBL201B for narrow tables where talkers sit on two sides, and the CBL301 for round tables or seats grouped on three sides.

AKG's official specification sheet for the CBL201 lists polar pattern, maximum SPL, current draw, output impedance, and physical dimensions, but it does not publish a frequency response curve, sensitivity rating, or self-noise level. The mic is voiced for speech rather than music recording, and most speech energy falls between roughly 300 Hz and 8 kHz. For rooms where measured self-noise numbers matter, ask about a mic with a published spec sheet before you order.