Speaker Zoning And Placement - Polycom SoundStructure C16 Design Manual

5½ foot from ceiling to ear distance which corresponds to an 11 foot loudspeaker separation from ceiling to
ear. If the listeners will be standing, more loudspeakers will be required to effectively cover the room as the
pattern of the loudspeaker will not cover as large an area closer to the loudspeaker.
Distributing the loudspeakers in the ceiling allows for all participants in the room to hear the sound well. If
there is only a single set of loudspeakers in the front of the room, then the audio in the back of the room
may sound reverberant and muddy, reducing intelligibility for the local participants. Similar to a microphone's
critical distance, loudspeakers also have a critical distance where the reverberant sound field is equal in
intensity to the direct sound field. If there are few loudspeakers (such as positioned at the front of a room),
then listeners near the critical distance will not receive an intelligible signal. By distributing the loudspeakers
throughout the room, it is generally possible to ensure that all listeners are well within the critical distance
of the loudspeakers.
In many audio conferencing rooms, there are separate loudspeakers for program audio such as VCR or
DVD to maintain the stereo separation of the source material in the room. There can also be a subwoofer
for this media, although subwoofers are typically not required for audio conferencing due to the limited range
of low frequencies produced by the typical human talker.

Speaker Zoning And Placement

As discussed in the previous section, ceiling loudspeakers should be positioned so the sound field from the
loudspeaker encompasses the participants' seating locations. This typically means that the loudspeakers
are positioned outside of the table perimeter to allow coverage of the participants and any potential areas
of overflow seating as shown in one possible layout of a room that is approximately 33x20 feet
(approximately 700 sq. ft.) in the following figure. As discussed in an earlier section, the microphones should
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