Earthworks CTB30 Boundary Microphone

by Michael Eddy
Earthworks' CTB30 Boundary Microphone
Earthworks' CTB30 Boundary Microphone

Earthworks is now shipping the CTB30 boundary microphone designed for conferencing and speech applications. Featuring audio and mechanical design innovations, the CTB30 delivers exceptional speech intelligibility, and coverage coupled with a low-profile appearance for lecterns, conference rooms, and classrooms.

Optimized for speech, the CTB30 features a flat frequency response from 60Hz to 30kHz and an incredibly fast diaphragm settling time that allows more subtle details of the human voice to be reproduced. Its True Semisphere™ polar response provides an omni semisphere of coverage and delivers the same high intelligibility of each orator speaking around the microphone without loss of high frequencies. The wide and even coverage across the microphone’s pickup pattern means that just one CTB30 can provide coverage for a 12-foot conference table that seats up to 12 people.

Incorporated into the microphone’s design is a specially engineered filter to significantly minimize the unwanted noises of table thumping, paper shuffling, and HVAC. The CTB30 also includes RF shielding to prevent interference from cell phones and other electronic devices.

Measuring just 4.1 inches in diameter, the CTB30 provides a very low profile miking solution and is available in black, white, silver or Nextel® Dark Black finishes.

The CTB30 comes with a 10 ft (3.04m) low profile cable with XLR-3M attached, and is designed to exit from the side or bottom of the microphone. The XLR can be removed, allowing the cable to run through a small hole in the table surface for a permanent installation.

Two 6-32 screw holes and a keyhole are found on the bottom of the microphone for secure mounting, allowing a more permanent installation option if required.

Further information from Earthworks Audio (