Vortex Media VTX 1000 - Manual (Page 70)

We will set Output D to -30 dB in order to protect the subwoofer from "bottoming out" on high-amplitude
transient sounds.
The output R1 is our Acoustic Echo Canceller (AEC) reference signal. This signal is what the internal AEC
uses to remove from the local microphones. In our example, we will remove the codec, telephone,
SoundStation VTX 1000, and program audio from the local microphones. Note that local microphones are
not included in the Reference Signal even though we are reinforcing them.
In this example, we will assume that the video codec and program audio outputs are designed to send
and/or receive a consumer level signal This signal represents the nominal level that the device will output
audio. Typically, this level is .3 Vrms. You can usually identify these types of devices if they use an "RCA"
connector. The Interface Module and subwoofer use RCA connectors.
We will set Output D to -30 dB in order to protect the subwoofer from "bottoming out" on high-amplitude
transient sounds.
The crosspoint levels for the reinforced microphones to Outputs 1 and 2 have been set so that people who
will be sitting furthest from the loudspeaker zone will receive the most amplification. Those who are sitting
closest to the loudspeaker zone will receive either no reinforcement or very little. Please note that the
overall goal of sound reinforcement is not to amplify everyone in the room at the same level to all
loudspeaker zones. Rather, the goal is to improve the intelligibility of the speech without altering the
listeners ability to spatially recognize who and where a talker is located in the room. If done correctly, the
electronic reinforcement should be transparent to those in the room and that is the reason for the different
crosspoint levels based on microphone and loudspeaker location in the room.
The output R1 is our Acoustic Echo Canceller (AEC) reference signal. This signal is what the internal AEC
uses to remove from the local microphones. In our example, we will remove the codec, telephone hybrid
audio, SoundStation VTX 1000 audio, and program audio from the local microphones.
Local Microphones should NEVER be included in the reference signal!
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