On the other hand, if one “pulls down” the conven-
tional Group Master Fader in the first example above,
the level of the double-assigned input will only drop 3
dB, whereas pulling down a VCA Master Fader will
completely kill any input channel assigned to that VCA
group.
Ultimately, the selection of VCA or conventional
Group Master Fader assignments should be dictated by
the specific requirements of the application.
7.2.3 Using The Channel Insert In Jackas a Line Input
The input channel INSERT IN jacks [102] are
electronically balanced, line level inputs that come after
the channel PAD switch and GAIN control. These jacks
may be used to accommodate any balanced or unbal-
anced +4 dBu nominal line input source. Why would
one want to use the 1/4" phone jack INSERT IN rather
than the XLR channel input? There are several possi-
bilities. Certainly, the most obvious is that if the input
source is equipped with a +4 dBu phone jack output,
then the INSERT IN jack enables a standard phone
plug-to-phone plug cable to be used without any adap-
tor. However, the INSERT IN jack also can save time.
7.2.4 Understanding and Using The MixMatrix
The PM4000 Mix Matrix consists of 11 smaller mix
level controls [28][29][30] and one larger MTRX MAS-
TER control [31] on each of the eight Master Modules.
These 96 controls can be thought of as a small mixer
within the larger console. In general, the matrix is used
to create different output mixes from the same set of
mixing busses. The matrix is considerably more conve-
nient and less costly than actually using an external
line mixer, and in the case of the PM4000, it is more
flexible as well.
Let’s “walk through” the PM4000 mix matrix. Each
matrix “channel” (a vertical row of controls) is identical.
All the Group busses (1-8), plus the Stereo bus (L & R)
are mixed to a mono signal using the individual matrix
mix level controls. Additionally, there is a SUB IN
control which adds a signal from the correspondingly
numbered MTRX SUB IN connector [110] to the matrix
channel mix. The overall level of the mix of these 11
sources can be adjusted with the MTRX MASTER
control.
If the PM4000 is being used for recording work, then
tape machine returns (playback from the tape recorder)
can be plugged into the INSERT IN jacks, while micro-
phones or other line level sources can be plugged into
the channel XLRs. When recording the basic tracks, the
channels’ PAD switches and GAIN controls can be set,
as needed, for the various input sources. When playing
back the multitrack tape, the PAD switches and GAIN
controls need not be readjusted; instead, simply engage
the channel INSERT ON switches [16] to select the tape
returns. The same concept applies where the console is
used for multiple stage setups (as in subsequent scenes
in a theatrical presentation, or different sets for a live
musical show). Provided one of the sources is a +4 dBu
line level source, it can be connected to the INSERT IN,
and the other mic or line level source can be connected
to the channel XLR; the INSERT switch then permits
instantaneous selection of one or the other input source
without need to disconnect and connect cables.
If you examine
the block diagram of the matrix
provided in Figure 7-3 (next page), you will see that the
level adjustments made in one channel of the matrix
affect only that matrix output. They do not affect levels
in any other matrix channel, nor do they affect any
other console outputs. On the other hand, assuming the
signals are fed to the matrix after the Stereo Master
Fader [58] and after the Group Master Faders [42]
(which is how the PM4000 is supplied from the factory),
then adjustments of the Group and Stereo bus output
levels will affect the levels applied to the matrix.
NOTE: The INSERT IN/OUT point on mono input
modules is after the channel EQ unless the INSERT
PRE switch is engaged [15]. Stereo input modules do
not have this switch, and are shipped with the insert
point being post-EQ. Internal jumpers on the each stereo
input module can be moved to change this to a pre-EQ
insert point, as explained in Section 6.5.
NOTE: The signal fed from each Group bus to the
matrix is factory wired so that it is derived after the
Group Master Fader. A slide switch in each Master
Module may be reset so that the feed to the matrix is
derived ahead of the Group Master Fader (see section
6.12). In that case, the Group Master Fader setting
would not affect the matrix levels. Similarly, the signal
fed from the Stereo bus to the matrix is factory wired so
that it is derived after the Stereo Master Faders. A pair
of slide switches in the Stereo module may be reset to
derive signal ahead of the L and R Stereo Master Faders
(see Section 6.13) in which case those Faders would not
affect matrix levels.
Page 7-7
The eight matrix channels can be used to create
eight different 11:1 mono mixes, or they may be used to
create four different 11:2 stereo mixes, or any combina-
tion of mono and stereo mixes. These multiple mixes
can be used for a variety of purposes, depending on the
application.