Teleconferencing Acoustics
Dec 8, 2010 10:58 AM, By Russ Berger
Considerations for successful teleconferencing.
The setup of the workshop included a demonstration room that was designed to simulate a larger conference room that could hold more than 16 people. Here, eight cardioid boundary mics, eight tabletop gooseneck mics, and eight ceiling mics were used to demonstrate various speech acquisition and reinforcement methods. Ceiling speakers were installed as well.
The Setup
Multiple manufacturers provided DSPs, microphones, and loudspeakers for the demonstration, and Sweetwater generously made its facilities available for the workshop. Each demo conferencing room was situated with remote-controlled high-definition cameras that allowed videoconferencing among all the spaces.
The first demonstration room was designed to simulate a large conference room that could hold 16 or more people. The setup involved eight cardioid boundary microphones, eight tabletop gooseneck microphones, and eight ceiling microphones to demonstrate various speech acquisition and reinforcement methods. Ceiling loudspeakers were installed at intervals above the seats to provide sound reinforcement for the in-room participants. High-definition cameras, a projector, and a screen connected this room with the second demonstration conferencing room and the lecture theater.
A small space was put into service as the second demonstration room. It simulated a smaller conferencing space for up to four people seated at a table. Multiple cardioid and omnidirectional boundary microphones as well as a ceiling omnidirectional microphone were used in this demonstration. A flatscreen television facilitated videoconferencing between the lecture theater and the demonstration spaces.
Sweetwater’s lecture theater features audio connectivity at each of the 250 seats, which allowed conference attendees to use personal headphones to critically listen to the adjustments in the audioconference system. In each of the demonstration rooms, screens simultaneously displayed images of the presenter, the large conference room, and the small conference room. In the lecture theater, both headphone monitoring and the house sound reinforcement system were used to connect and monitor the two conference systems’ output.
During the workshop, participants were able to clearly hear the difference between the various mic techniques and detect the nuances of the different flavors of DSP and programming applied to overcome the acoustical issues of an imperfect, multimicrophone teleconference. It was evident that increasing the number of open mics makes quiet space even more critical, both in cumulative room noise and the ability of listeners to distinguish among multiple participants.
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