Audio Developments AD149 User Manual

Page 24

Our customers know we are totally committed to providing them with facilities for
working in the M-S domain. The new monitor module enables engineers to take
advantage of ALL Blumlein's techniques; both during recording and during post-
production.

We believe that the monitor path is as important as the main signal-path and one that
tells less than the whole truth is valueless. When designing AD146, space was at a
premium by the time we arrived at the monitoring section and several (what appeared
to be) compromises had to be made. The 'compromises' proved so flexible and
versatile, they have been retained in all succeeding models. Because of space
constrictions, monitoring had to be simplified - with the following result.

The main monitor path - MONITOR 1 - is addressed via the MON switch on each
input module. The secondary monitor path - MONITOR 2 - feeds the stereo-
headphones' jack and is addressed via the PFL switch on each input module. BUT -
monitor 1 output automatically drives monitor 2 output until any PFL switch is pressed,
when logic changes the source of monitor 2 output to the stereo PFL busses. (When
all PFL switches are released, once again monitor 2 equals monitor 1.) This system
has now been refined - even further: when using monitor 1 as the main monitor -
probably for loudspeaker listening - it is possible to route PFL (which normally only
appears on headphones) to monitor 1 by selecting SPLIT (monitor). Pressing a PFL
switch will now have the following effect: any stereo signal being auditioned on
monitor 1 will be mixed to mono and presented to monitor 1 left-output only; PFL will
be mixed to mono and presented to monitor 1 right-output only. As will be seen later
(page 66), (mono) PFL can be isolated and presented to both left and right outputs
simultaneously.

The monitoring system allows an input channel to be auditioned in three ways:

(a) PFL;

pre-fader listen

(b) AFL;

after-fader listen

solo-in-place (non-destructive)

The output module is almost identical with the one designed for AD146 but with
simplified meter switching. 'At rest' the meters read L-R output, but this can be
overridden in turn by auxiliary 1 & 2 outputs, monitor 1 output and stereo PFL.

Attack and release times of the main-output limiters may be selected on DIL switches
on the module's left-hand PCB.

A matrix amplifier - see M-S NOTES - may be inserted in the main L-R output and
across auxiliary 1 & 2 outputs.

By request, auxiliary masters are potentiometers rather than faders, but we have
included a link switch so that they may be operated as a stereo pair.