Boundary microphones

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  • Specially engineered filter to minimize table thumping and HVAC noise
  • Reduced pickup of paper shuffling
  • 30kHz flat frequency response optimized for speech
  • Ultra high intelligibility
  • More gain before feedback
  • Near perfect polar pattern
  • True Semisphere™ omnidirectional polar pattern
  • RF resistant
  • Rubber, shock absorbing pads eliminate vibration noise
  • Designed to allow cable to exit from the rear or bottom of the microphone
  • Low profile design
  • Only 4.1 inches (10.4cm) in diameter
  • Available in black, white, silver or Nextel® Dark Black finish
  • Primary applications include teleconferencing, distance learning, surveillance, boardrooms, government facilities, and ambient room miking

The Earthworks CTB30 High Definition Boundary Microphone™ is the perfect choice for high quality teleconferencing applications. It is a low profile, pristine sounding microphone solution for any conference or huddle space. Its extended high frequency response to 30kHz and Omni Semisphere™ polar response provide the same high intelligibility at virtually any point around a conference table or other surface on which the microphone is mounted. In addition, the extremely fast diaphragm settling time allows more subtle details and nuances of the human voice to be reproduced, which adds to the incredible clarity and intelligibility of the CTB30 at various distances from the microphone.

The CTB30 incorporates a unique filter that significantly reduces low frequency table thumping and HVAC noise. In addition, it delivers an impressive reduction of unwanted sounds from paper and pens. Like all Earthworks microphones, the CTB30 is completely immune to RF interference from mobile phones and other RF sources. Measuring just 4.1 inches in diameter, the CTB30’s sleek design fits seamlessly into any room.

CTB30-B 30kHz omni, black finish

CTB30-NB 30kHz omni, Nextel® Dark Black finish

CTB30-S 30kHz omni, silver finish

CTB30-W 30kHz omni, white finish

Frequency Response: 60Hz to 30kHz -3dB @ 1 ft (30cm)

Low Frequency Rolloff: 60Hz, 15dB/octave

Polar Pattern: Omni Semisphere™

Sensitivity: -25dB

Power Requirements: 48V Phantom, 10mA

Max Acoustic Input: 136dB SPL

Dynamic Range: 116dB @ 1kHz

Output: XLR-3 (pin 2+)

Output Impedance: 65Ω balanced

Min Output Load: 1K between pins 2 & 3

Noise: 19.5 dBA (Typical)

Microphone Color: Black, White, Silver or Nextel® Dark Black

Dimensions: 4.1 x 4.1 x 0.45 inches (104.1 x 104.1 x 11.4mm)

Cable Length: 10’ (3.04m) with installed XLR-3M

Connector Type: Low profile cable terminated into a 3-pin XLR-M

Weight: 0.36 lbs. (162g)

Polar Response

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Frequency Response – 45 Degrees Incidence

frequency_imb30 FINAL2-01

Impulse Response