Yamaha PM4000 Operating Manual page 8

The PM4000 is a professional audio mixing console
with the kind of flexibility, performance and reliability
for which Yamaha has earned a worldwide reputation.
It picks up where the famous PM3000 left off, with still
more functions, a higher level of performance, and a
greater degree of versatility than ever before. The
console now comes with both mono and stereo input
modules, and you can determine the complement of
each type of module in your unit at the time you order
it, or you can later swap modules in the field (between
shows if need be).
The console is available with 24, 32, 40 or 48 input
positions (24 channel versions are available in the
U.S.A. only on special order). However, if fully config-
ured with stereo input modules, the actual number of
input sources is substantially higher (the mix of mono
and stereo modules can add up to no more than 64 in-
put channels per mainframe, as limited by power
supply capacity). There are eight VCA (Voltage Con-
trolled Amplifier) Master Faders which can be assigned
to control any combination of input channels (see
Section 7 for a discussion of VCAs). In addition, there
are eight group mixing busses, as well as a stereo
mixing bus, to which any of the input channels can be-
assigned. There are also eight monaural auxiliary
mixing busses and two pair of stereo auxiliary mixing
busses to which each input channel may be assigned by
means of sealed PRE/OFF/POST switches and Send
Level controls. The stereo aux busses may be switched
to dual mono busses, for a total of twelve busses that
can be used to augment the eight groups plus the stereo
bus for a total of 22 audio mixing busses, or they may be
used for a combination of foldback send (stage monitor),
effects send and remote mixes.
Input channel signals may be assigned directly to the
stereo bus, or assignment can be made via the Group
Masters. Thus, the console can function in a sub-
grouped mode with a stereo "grand master" fader, or it
can function with independent stereo and multi-channel
output mixes.
The PM4000 inputs are differentially balanced, and
are equipped with a 30 dB attenuation PAD plus a
continuously variable 50 dB range GAIN trim control so
that literally any mic or line level signal can be accom-
modated with channel faders set at nominal level.
Optional input transformers may be installed internally
on a channel-by-channel basis when extra grounding
isolation is required. While the console has ample
headroom throughout, it is always possible to incor-
Section 1.
Introduction
rectly set controls. For this reason, the PM4000 is
equipped with level detection at several stages. Input
LED meters and "PEAK" LEDs are provided. The latter
not only monitor the input preamp level, they check for
overboost in the EQ section. too. Metering can be front-
panel switched to pre or post fader (actually, pre/post
VCA). Finally, if the mixed levels on the group, auxil-
iary, stereo, matrix or cue busses adds up to be too high,
a "PEAK" LED in the output meters will flash on to
warn of the impending danger of clipping.
Naturally, the PM4000 is equipped with a Mix
Matrix, the feature Yamaha pioneered in professional
audio consoles. The PM4000 Mix Matrix is an 11x8
configuration. That is, there are 11 possible sources that
can be mixed together into one output. Those 11 sources
can be mixed together eight different ways on eight
different modules. Each matrix channel accepts a direct
sub input from a rear panel connector, plus signals from
the stereo bus (L&R) and the eight subgroups (pre or
post master fader, depending on internal preset
switches). These 11 sources all go through a MATRIX
MASTER control and an on/off switch to a discrete rear
panel output. The matrix can save a tremendous
amount of time and effort when you want to set up
stage monitor mixes from the subgroups, when you
want to create different speaker mixes for different
zones of the house, to feed local and remote programs
simultaneously, to make mono and stereo mixes from
the same subgroups, and so on. In fact, if the matrix is
set to pick up the subgroups ahead of the Group Master
Faders, then the subgroups can be mixed onto the
stereo bus with one mix, and completely independent
mono or stereo mixes can be achieved from the same
subgroups via the matrix.
The PM4000 has a VCA grouping system which is
separate from the audio grouping. Eight "VCA GROUP"
switches next to each channel fader enable that channel
to be assigned so it is controlled by one or more of the
VCA Master Faders. When multiple input channels are
assigned to a given VCA bus, those channels output
levels can be raised or lowered by the single VCA
Master Fader. Consider how this differs from the
conventional groups. When multiple input channels are
assigned to one of the eight group (audio) mixing
busses, those channels' combined signals can be raised
or lowered in level with the Group Master Fader. The
audio result is the same as though the VCA Masters
were used... with one exception; if signal processing of
multiple inputs is required, it is necessary to run that
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