Polycom Vortex EF2241, Application Note

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G
AIN
S
TRUCTURE
M
ICROPHONE
L
EVELS
For wired microphones, the input gain on the Vortex is dependent on the sensitivity of the microphone as
well as the typical distance from the talker to the microphone.
Table 1. Recommended microphone settings.
Type of Microphone Average Level
Tabletop Mic Mode, 15 dB
Ceiling Mic Mode, 25 dB
Podium Mic Mode, 10 dB
Gooseneck Mic Mode, 5 dB
Wireless Depends on the receiver*
*Some wireless receivers transmit audio at line level (approximately 0 to -10 dB) and others transmit at mic
level (approximately -30 dB). Based on the transmit level, you may need to apply gain in the Vortex Device.
For example, if a wireless receiver's nominal transmit level is -10 dB, you will need to apply +10 dB on the
input of the Vortex Device to achieve unity (0 dB) gain.
In order to set the gain appropriately, we recommend leaving all processing enabled and having someone
talk into the microphone. Have another person watch the levels in Conference Composer or via the front
panel of the Vortex device. You want the speech to light up the first yellow LED (0 dBu) and flicker the
second yellow LED (+3 dB) during normal conversation. This level indicates that the Vortex device has a
good level for processing while having about 20 dB of headroom.
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