Microphone arrangements for teleconferencing from rooms which are particularly noisy or reverberent pose difficult problems for the acoustic engineer. The Washington D. C. Room of the General Service Administration Teleconference Network was such a room. Pronounced end‐to‐end flutter echos were apparent to the casual listener, the ambient noise level was 45 dBA and corridor noise, air‐conditioner noise and airplane fly‐over noise were present. Using the acoustic guidelines for teleconferencing (Stockbridge et al.) a microphone‐talker separation of 12 in. was determined. To satisfy this 12 electret, tie‐clasp microphones were mixed together and fed to a teleconferencing terminal. Walnut cabinets were designed to house the mixers and provide table‐top storage of the microphones when not in use. The use of voice gates to prevent noise buildup from multiple live microphones was explored and found to be unnecessary. The final system configuration eliminated the problems inherent in this room for teleconferencing.

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