Handbook for Sound Engineers

930 Chapter 25

25.15.11 Auxiliary Channel Feeds

Two prefade (and so premute) feeds are provided on
each channel, each with a level control and pannable
across a stereo pair of mix-buses. This provides a versa-
tile facility enabling separate stereo foldbacks or four
separate feeds. Each of the pairs is selectable to post-
fade should extra effect feeds be needed during a heavy
mixdown, whereupon they will also be subject to
channel mutes. A few effects such as stereo reverbera-
tion plate/black box would benefit enormously in opera-
tion if they could be sourced from stereo auxiliary feeds
such as these.
Four individual postfade effect feeds are individually
mutable (locally or remotely), individually level
controlled, and selectable to prefade.
Effect feeds are quite often switched during mixes;
consequently, analog transmission gates are used, facili-

tating automation. Local activation is achieved through

the debounce/latch arrangement used extensively in the

channel mode switching, Figs. 25-99 and 25-101. The

latch output drives a simple, single-element transmis-

sion gate. Isolation, crosstalk, and noise criteria are not

particularly critical on these feeds, but they still come

out quite creditably. The console switch-on master reset

bus (MRB) cancels all these feeds, leaving a clean slate

rather than the alternative unpredictable hordes of ons,

offs, and maybes in the event of a power interruption or

control zeroing.

25.15.12 Summing Modules

Much of the actual mixing within the system described

so far is self-contained. Multitrack routing, when

achieved via a matrix, allows multiple sourcing to any

Figure 25-101. Channel auxiliary sends and logic control—Auxiliary sends channel.

From prefade takeoff

From postfade takeoff

IC 7 NE5534

IC 5 Transmission gate 4066