User guide Andante 8
page 17
Gating
The automixer unit controls the microphone’s state as following:
If the RMS level is above the current adaptive threshold, the microphone’s state is open i.e. the block applies no
attenuation to the signal.
If the RMS level is below the current adaptive threshold, the microphone’s state is attenuated i.e. the block
applies an off attenuation to the signal.
Adaptive Threshold
The internal algorithm dynamically sets the gate threshold level in accordance with the ambient noise. For
example, in a noisy room the automixer would increase the threshold level to prevent any of the microphone
channels from being triggered on by the noise. On the other hand, in a quiet environment, the threshold level
must be lowered.
Last Microphone Hold
Die Funktion „Last Microphone Hold“ lässt das zuletzt aktivierte Mikrofon offen,
auch wenn der Schallpegel unter den eingestellten Schwellenwert fällt.
Selecting
This LED is on when the microphone channel is gated on.
For those input channels with automixer mode disabled, this LED is always off.
Insert I/O
Turns on/off channel gating. When disabled, the microphone state for this
channel remains bypassed (no automixer mode) at all times and its level
does not contribute to adaptive threshold computing or NOM attenuation.
Hold Time
Sets the minimum time an microphone stays open after the user stops talking
(i.e. RMS input level drops below the adaptive threshold level).
Use this control to prevent the gate from opening and closing due to
momentary pauses in speech.
Typical values are comprised between 1 second and 2 seconds.
Attenuation
The off attenuation parameter allows attenuation of inactive inputs from 0 dB to -60 dB.
When hold time is elapsed, the off attenuation is smoothly inserted.
Practical experience has shown that a 15 dB
– 20 dB attenuation is a good compromise.
NOM GAIN
When NOM GAIN is active for a channel, the automixer will reduce
the gain for the given channel by 3 dB
for every doubling of open channels (-10log(NOM) rule).
The NOM GAIN, if enabled,
is singularly applied on each channel.
Priority
has relevance to assign preference on opening channels.
Compatibly with the actual number of open microphones, the channels with higher priority
will be opened before of the lowest ones.
It does not mean strictly that microphones with higher priority can override ones with lower priority.
Generally, each time two or more channels must be opened, priority level is used to give a precedence order.
Priority increases from 1 (lowest) to 5 (highest).
A special case of priority behavior regards the highest priority that serve to disable all other channels.
With PRIORITY equal to 5, use the additional parameter
RESET TIME
to determines how long to wait for channel restoring.
Typical values of RESET TIME are between 1 second and 5 seconds.
Application example:
The highest priority reveals useful inside churches during organ playing, where a separate
microphone with PRIORITY equal to 5, placed close to the organ pipes, gates off all
microphones in presbyter.
NOTE:
When you set up your mixing system, make sure you get the right gain on the analog input
gain control. Automixer works better when the gain has been properly set to give the
algorithm adequate signal.
For automixer proper working, best microphone level range is between -40 dB and -10 dB on Peak Level Meter.
NOM
NOM GAIN
1
0 dB
2
-3 dB
3
-3 dB
4
-6 dB
5
-6 dB
6
-6 dB