20 (Solo) Led; Ol (Mute) Led; Mute; Pan - Mackie 1642VLZ4 Owner's Manual

Level set (PFL) taps the channel signal before
the fader. If you have a channel's fader set way
below "U" (unity gain), solo won't know that
and will send a unity gain signal to the control room,
headphones, and meter display. That may result in
a startling level boost at these outputs, depending
on the position of the solo [46] level knob.
In a nutshell, soloed channels are sent to the source
[42] mix, that ultimately feeds your control room,
headphones and meter display. Whenever solo is
engaged, all source selections (main mix, 1–2, 3–4,
and tape) are defeated, to allow the soloed channel
to do just that — solo!
28. –20 (Solo) LED
An LED that does two completely different things!
This saves space, but requires some explanation.
First, the "–20" part: Often referred to as "signal
activity," this LED will flicker in time with the signal
present in that channel. It's handy for confirming that
a channel is indeed active, and may also lend a clue
as to what the signal is. For instance, a kick drum will
cause the LED to pulse in time with the drum, and
a synth pad will cause it to glow a bit more steadily.
Now for the "solo" part: When a channel's solo [27]
switch is engaged, this LED will glow steadily. It will
also be brighter than it would be as a –20 indicator.
In conjunction with the rude solo light [47], you can
find a rogue solo switch very quickly.

29. OL (Mute) LED

Another LED that does two different things!
First, the "OL" part: "OL" means overload, or clip. You
don't want that to happen. Ever. Clipping can happen
to any mixer — it's the point where the signal's volt-
age tries to exceed the supply voltages that power the
circuitry. This OL LED will come on just before clipping,
so if you see it, take immediate action: Perform the
level-setting procedure. If that doesn't help, check for
excessive use of EQ boost or fader gain. Like the –20
LED, it will flicker in time with that channel's signal.
Now for the "mute" part. Assuming your levels are set
correctly, the OL LED will never come on as a result of
clipping. That's pretty boring. So, to liven things up, this
LED will glow steadily when that channel's mute switch
is engaged.
Here is a quick reference to these LEDs:
Name Color Flickering
–20 (SOLO) green signal present
OL (MUTE) red channel clipping

30. Mute

Engaging this switch provides the same results
as turning the channel's fader all the way down:
Any channel assignment to L-R, 1-2 or 3-4 will be
interrupted. All the post aux sends will be silenced,
as will the direct out signals on channels 1 through 8,
and the OL (mute) LED will glow. The pre aux sends,
channel insert send, and solo (in level set (PFL) mode)
will continue to function during mute.
Depending on the audio content in a channel,
engaging its mute switch may cause a slight popping
sound. This is not a problem within the mixer, and it
can be avoided: Simply engage the low cut [34] switch
on each channel (unless its low frequency content is
vitally important, such as a kick drum or bass guitar).
Low cut eliminates subsonic debris, which causes the
pop, and its effect is usually transparent.

31. Pan

Pan adjusts the amount of channel signal sent
to the left versus the right outputs. Pan determines
the fate of the L/R assignment, subgroups 1–2 and 3–4,
and the solo [27] (in AFL mode).
With the pan knob hard left, the channel signal will
feed the left main mix, subgroup 1, subgroup 3 and left
(AFL) solo mode (assuming their assignment switches
are engaged).
With the knob hard right, the channel signal feeds
the right main mix, subgroup 2, subgroup 4 and right
(AFL) solo mode.
With the pan knob set somewhere in-between left
and right, the signal will be divided between the left
and right buses.
The pan knob behaves a little differently for the
stereo channel strips. Since there is a left and right
input on these channels, the pan knob controls the
relative balance between the left and right sides, just
like the balance control on your stereo system at home.

Stereo Sources

Use channels 9-16 to connect stereo sound sources.
If you must use the mono channel strips (1-8) for stereo
sources, follow this standard convention: Always plug
the left signal into an "odd" channel (1, 3, 5, etc.) and
the right signal into the adjacent "even" channel (2, 4, 6,
etc.). Then pan the odd channel hard left and the even
channel hard right.
Glowing
channel soloed
channel muted
Owner's Manual
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