10. NOM Function (Autom
0. NOM Function (Automatic Mixing-MIXER Mode)
atic Mixing-MIXER Mode)
a. How do I program the 9000 for Auto-Mixing?
a. How do I program the 9000 for Auto-Mixing?
The 9000 Series Auto Mixing function is simple, but very effective. This is used for
conference rooms, court rooms and other live venues and is designed to minimize two
problems associated with multiple microphone applications:
The 9000 Series Auto Mixing function is simple, but very effective. This is used for
conference rooms, court rooms and other live venues and is designed to minimize two
problems associated with multiple microphone applications:
1.
Sensitivity to feedback, due to increased system gain as microphones become active
1.
Sensitivity to feedback, due to increased system gain as microphones become active
2.
Cross-talk from mic-to-mic, which can also not only increase feedback, but decreases intelligibility.
2.
Cross-talk from mic-to-mic, which can also not only increase feedback, but decreases intelligibility.
The Auto Mixing function helps to overcome these problems by employing two stages of
mixing control:
The Auto Mixing function helps to overcome these problems by employing two stages of
mixing control:
1. Gating:
This keeps crosstalk to a minimum by turning off microphones that are not used at a
given time. When a speaker begins speaking into the microphone (above the threshold level), the
gate opens to allow audio to pass through. When the speaker stops, the gate closes again to
maintain a quieter background.
1. Gating:
This keeps crosstalk to a minimum by turning off microphones that are not used at a
given time. When a speaker begins speaking into the microphone (above the threshold level), the
gate opens to allow audio to pass through. When the speaker stops, the gate closes again to
maintain a quieter background.
2. NOM (Number of Open Microphones).
This process works on the principal that for every time
the number of live or “open” microphones is doubled, the overall volume increases by 6dB.
Therefore, we would need to reduce the system’s level by 6dB in order to maintain a consistent
volume and prevent feedback. The NOM calculation is a logarithmic function represented as:
xlogNOM (with x being the attenuation factor). A value of 10logNOM will reduce the system level
by 3dB for every doubling of open mics. A value of 20logNOM will reduce the level by 6dB. Then,
if we go from 4 live microphones to 8, a setting of 20 would automatically reduce the system by
6dB-maintaining the correct level.
2. NOM (Number of Open Microphones).
This process works on the principal that for every time
the number of live or “open” microphones is doubled, the overall volume increases by 6dB.
Therefore, we would need to reduce the system’s level by 6dB in order to maintain a consistent
volume and prevent feedback. The NOM calculation is a logarithmic function represented as:
xlogNOM (with x being the attenuation factor). A value of 10logNOM will reduce the system level
by 3dB for every doubling of open mics. A value of 20logNOM will reduce the level by 6dB. Then,
if we go from 4 live microphones to 8, a setting of 20 would automatically reduce the system by
6dB-maintaining the correct level.
We will find these settings in the
I/O Configuration Page:
We will find these settings in the
I/O Configuration Page:
1
2
5
4
3
1. GATE:
Checking this box activates the Gate function for each microphone.
1. GATE:
Checking this box activates the Gate function for each microphone.
2. GATE THRESHOLD:
Sets the level which the input must exceed in order to “open”
the Gate (-5 to -40dB range).
2. GATE THRESHOLD:
Sets the level which the input must exceed in order to “open”
the Gate (-5 to -40dB range).
3. GATE REALEASE TIME
: The time it takes for the Gate to close again once input
signal has dropped below the threshold.
3. GATE REALEASE TIME
: The time it takes for the Gate to close again once input
signal has dropped below the threshold.
4. NOM
- Activates the NOM attenuation functions for the selected mics.
4. NOM
- Activates the NOM attenuation functions for the selected mics.
5. NOM ATTENUATION
: Sets the attenuation rate for the NOM function (1-20). A setting
changed for one microphone affects all mics for which NOM has been activated. A
setting of 20 provides the maximum attenuation, with 1 being the minimum. (*See
NOM Table in the
Chapter 13- Misc
.).
5. NOM ATTENUATION
: Sets the attenuation rate for the NOM function (1-20). A setting
changed for one microphone affects all mics for which NOM has been activated. A
setting of 20 provides the maximum attenuation, with 1 being the minimum. (*See
NOM Table in the
Chapter 13- Misc
.).
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