EAW DX1208 Help File page 35

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Meter
Master Output Parameters
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Channel Select
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Enable
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Fader / Gain
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Meter
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Current Automix Level
Automixer
Description
Automixers are designed to emulate a skilled human operator using a traditional mixing
console to mix multiple speech inputs together. Typical multi-source speech environments,
such as are found in boardrooms, courthouses and city council chambers, conference
facilities, and even theaters, present numerous challenges to both human and automatic
mixers. Speech intelligibility suffers when unused microphones pick up reverberance and
unwanted room noise. Additionally, increasing the number of open microphones decreases
the overall system gain before feedback, making it harder in larger systems to apply sufficient
gain to make the on-mic sources audible. The fast pace of unscripted dialog exchange also
makes it exceedingly difficult to anticipate when gain changes are required, and can lead to
speakers' words or sentences being cutoff before the operator can react.
There are two types of automixers commonly used today: gain sharing, and gating automixers.
Gating automixers use noise gates on each automix channel that open and close when a user-
defined threshold is exceeded. With this method the number of microphones can change from
moment to moment, and for this reason the more sophisticated gating automixers allow you
limit the number of open microphones (NOM) to prevent feedback. While gating automixers
are good in certain applications, in general they are harder to setup (especially with larger
systems), and the gating effects can sometimes be heard both on individual channels and in
the overall system as background noise is modulated with the NOM.
The DX1208 employs a gain sharing automixer, which works on the basis of expanders, rather
than gates. Instead of each microphone being turned on or off, all microphones are on all the
time, and the overall system gain is distributed amongst them. As one source gets louder with
respect to the other sources, it receives a proportionately larger share of the overall gain; as
another gets quieter, it receives a proportionally smaller share of the gain. The advantage of
this is that it is easy to optimize the system for maximum gain before feedback, especially in
Displays the instantaneous peak signal level of the Input Channel,
pre-Fader and pre-Enable.
Selects the Matrix Output Channel that is controlled by the
Automixer tab.
Enables the Matrix Output. When [Disabled], no audio passes to
the Output Channel.
Controls the overall gain of the Matrix Output. Adjust the gain
either by dragging the fader handle or entering a value (from [+20]
to [-99 dB]) into the text box to the right of the Output.
< CTRL+CLICK> in the Master Output Meter to reset the Fader to
unity.
Displays the instantaneous peak volume level of the Matrix
Output, post-Fader and post-Enable.
This text box displays the gain (in dB) of the last Matrix
Channel whose Fader was adjusted.
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