Toa AX-1000A, Руководство по эксплуатации

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NOM Attenuation Adjustment
The typical automatic mixer reduces its output gain according to the formula 10 log NOM, where NOM refers to the
" N umber of O pen M icrophones" --that is, the number of microphones which are active at any given instant. If two
channels are gated "on", the mixer's overall output gain is reduced 3 dB; if four are "on", the master gain is
reduced 6 dB; and so on.
In some cases it might be important to adjust attenuation differently. For example, if microphones are set up in
very close proximity to loudspeakers, or if the acoustic space is extraordinarily reverberant, the master gain should
be attenuated by a factor greater than 10 log NOM. This gives better feedback protection as more channels gate
"on". On the other hand, if the AX-1000A is located in an extremely dead acoustic space, attenuation at less than
10 log NOM will result in smoother automatic mixing.
The AX-1000A can be operated as a conventional manual mixer with the NOM Attenuation set to 0 log NOM.
7. Output Configuration
Main Output Connections
Connect the power amplifier(s) to the output terminals.
To choose 150 ohm output:
To choose 600 ohm output:
Remote Master Volume
If remote control of the master volume is required, utilize a 10k ohm linear potentiometer across these terminals.
The 10k ohm setting yields full volume, and the 0 ohm setting results in no output. Note that the Remote Master
attenuates from the level set by the Master Volume Control. It does not boost the volume.
Remote Master is useful for overall volume control when a security cover prevents access to Master Volume
Control.
If remote control of only one or two discrete volume setting is desired, use a toggle switch or a rotary switch with
fixed resistors to present the appropriate resistance across the Remote Volume Terminals.
For example, there may be a switch on the podium for "System Off" in one position, "Lecture/Discussion" in one
position, and "Movie/A-V" in a third position. This simplifies operation by untrained personnel.
Here, "System Off" would silence the AX-1000A by shorting the terminals; "Lecture/Discussion" would set the
volume to a middle value; and "Movie/A-V" would permit full volume.
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