Microphones For Conferencing - Polycom SoundStructure C16 Design Manual

Microphones For Conferencing

While omni-directional microphones seem like a natural choice for conferencing applications as fewer
microphones would be required for a given number of participants, their 360 degree pick up will pick up extra
noise, room reverberation and the remote audio from the loudspeakers. The result will be that the signal
picked up by the microphone in a conferencing environment will sound muddier and noisier than the signal
from a directional microphone. It is for this reason that most installations use cardioid style microphones.
The style of microphone is determined by how the participants will use the conference room. It is common
in rooms where there is a great deal of collaboration or sharing of drawings, documents, etc. to get the
microphones off the table and have them in the ceiling. This allows for much sharing of paperwork without
the concerns or complaints of the sounds of paper as it slides across the microphone elements.
Gooseneck Microphones
In many board rooms, gooseneck microphones are used and distributed around the table with one
microphone per participant. Each of these microphones will have a neck that takes the microphone off the
table and brings it closer to the local talker's mouth. In addition these microphones will have a directional
pattern to further improve the rejection of the ambient noise. One consideration to remember is that some
gooseneck microphones have a tendency to straighten-out over time, so it is recommended that the
microphone positioning be checked periodically to ensure that the gooseneck microphones are not pointed
directly at loudspeakers.
Tabletop Microphones
In many conferencing applications boundary tabletop microphones are used and mounted at locations
around the table as shown in the following figure where one microphone is used for each two participants.
Polycom, Inc. 720