Allen&Heath WZ16 2 - Manual (Page 15)

A- B OUTPUT
The A-B output is an additional stereo/mono output that can be
uniquely configured as either a separately controllable mix
output, or a local loudspeaker monitor feed.
MODE SWITCH - This switch is recessed under the panel to
prevent accidental operation. It is operated using a pen tip or
similar pointed object. In the normal up position A-B follows the
main L-R mix. When pressed A-B follows the monitor switchbank +
PFL to become a 'local' monitor in addition to the headphones.
POST/PRE - This recessed switch selects whether the L-R signal
fed to A-B is sourced pre or post the L-R faders.
LEVEL - Adjust the output level using this control. Up to +10dB of
boost is available above the nominal '0' position.
MONO - Sums L+R into mono. When A-B is configured as an
additional mix output the MONO switch provides a mono output
ideal for centre fill or sub-bass loudspeaker systems, or mono
recording and broadcast feeds. When A-B is configured as a local
monitor the MONO switch lets you check the mono compatibility of
the selected mono source. Alternatively you can feed a local mono
speaker monitor such as an engineers listen wedge.
Here are a few applications of the versatile A-B output:
L-R stereo live recording / broadcast
mode = up, set pre-fade
level trim to match recorder, L and R out
Mono live recording / broadcast
mode = up, set pre-fade, mono selected
level trim to match recorder, 2x M out
Additional L-R zone speakers
mode = up, set pre or post fade
level trim to balance speakers, L and R out
L-R delay fill speakers
mode = up, set post-fade
level trim to balance to main, L and R out
Mono centre fill speaker
mode = up, set post-fade, mono selected
level trim to balance to main, 2x M out
Sub-bass speaker
mode = up, set post-fade, mono selected
level trim to balance to main, 2x M out
Local stereo speaker monitor
mode = down
separate monitor level, L and R out
Local floor listen wedge monitor
mode = down, mono selected
separate monitor level, 2x M out