Consoles 82525.1 IntroductionMixing consoles are an immense subject; their under-
standing though is a key to professional audio. In this
section consoles are discussed from the basics of their
architectures, features, design elements, and all the way
through to DSP and its implementation in digital mixer
design. Consoles abound in forms quite unlike the tradi-
tional big sea of knobs. Productions huge and modest
are regularly done with a screen and a mouse—indeed,
nearly everywhere in operations that don’t require
immediate access to controls, mostly live. But consoles
they are; they’re just hiding in unfamiliar shells; their
schema are, despite outward appearances, directly trace-
able to traditional audio architectures.
Commercial mixing consoles live or die not just on
how closely they fit their particular application; a
several-hundred-thousand-dollar buy decision is often
made on things as fiercely disparate as more or less
favorable finance schemes and the way consoles sound
(or more often are reputed to sound). This section does
not include console cost other than drawing distinctions
between straightforward and extravagant approaches,
but it does explore many aspects of what makes
consoles sound better or worse.
Along the way, explanations are given of what each
common control does and how it is normally used and
why. Examples of how they have developed and been
implemented in electronics are also given. A range of
console arrangements (architectures) gives enough clues
to analyze how any encountered system actually oper-
ates. Description of circuitry and techniques is less
theoretically driven than practically derived, with no
apologies given for blow-by-blow analyses of real
commercial multitrack mixing console designs. It is
hoped that this will augment and lend perspective to
earlier descriptions of typical circuit blocks.
Seemingly the only thing preventing most mixers
from being digital nowadays is that the cost benefit for
many applications has not yet tilted far enough in that
direction; although hardly mature, the technology and
the available quality are not impediments. Given that,
one might question why this chapter retains a lot of
“analog stuff.” The answers are manifold: A lot, argu-
ably still most, of mixers in use today are still analog
and far from a prediction made in the mid-eighties that
the Last Great Analog Console had probably already
been built, manufacturers both established and new
seem to think it worthwhile to wheel out new analog
behemoths once in a while. And, almost in mirror
fashion, at the low end of the market economies of scale
and slim margins still preclude digital on cost alone,
where any meaningful control surface is needed. But
those aren’t the main reasons consoles exploded,
evolved, and matured operationally in the same era as
similarly burgeoning analog technology; the technology
inevitably influenced the application with its own ratio-
nalized costs and limitations. The applications
—consoles and their constituent signal-processing
elements—are nowadays being emulated digitally. Yes,
a huge amount of the engineering of digital mixing
consoles is in accurately recreating foibles inherited
from their analog ancestors, good or ill. It behooves one
to understand why things ended up the way they did, so
that one can optimally progress into the new domain. It’s
called learning from history, only in this case the history
is still very much alive and has its teeth.
An overview of digital signal processing as applied
to consoles will, as deeply as it is possible to go before
nasty equations arise, give an insight into how these
things work—at first blush it all seems black
magic—really it’s just a lot of black chips each with a
specific and usually straightforward purpose. Similar to
the way that a real analog console design is dissected
and explained in the following pages, a real digital
console design is broken down for overview and
analysis.
Parallel, and indeed prior, to the incursion of DSP
audio was digital control of audio. Although DSP and
digital control necessarily go hand in hand, digital
control of analog techniques are overviewed here, too.25.1.1 Console DevelopmentThe establishment of consoles was a slow and gradual
process. Similarly, systems—or preorganized arrange-
ments of devices—evolved slowly, too. In most audio
work the two are now considered as almost synony-
mous; the greatest departure from this is the inclusion of
a console as part of a system. But even then, there is no
doubting that the console is the heart and substance of
the system.
The history of consoles reaches back to the time
when the recording process was purely mechanical, Fig.
25-1, followed by its electrical analog, Fig. 25-2, which
included a source transducer (in this instance a micro-
phone), a means of gain (an amplifier), and an output
transducer (a disk-cutting head). It doesn’t take a stag-
gering amount of imagination to extend this system to
embrace other applications: public address, acoustic
enhancement of natural sound by electronic means, Fig.
25-3; disk replay, Fig. 25-4; and broadcasting by
replacement of a simple electromechanical transducer
by a radio transmitter, Fig. 25-5. The objective of the