When doing live sound or mixdown, it’s often handy to control the level of several channels with one knob. That’s called subgrouping. Simply assign these channels to the ALT 3-4 mix, engage ALT 3-4 in the CONTROL ROOM/PHONES SOURCE matrix (20), and the signals will appear at the CONTROL ROOM (48) and PHONES
(42)outputs. If you want the ALT 3-4 signals to go back into the MAIN MIX, engage the ASSIGN TO MAIN MIX switch (21) and the CONTROL ROOM knob (22) controls the levels of all the channels assigned to ALT 3-4.
Another way to do the same thing is to assign the channels to the ALT 3-4 mix, then patch out of the ALT 3-4 OUT (LEFT/3 and RIGHT/4) back into an unused stereo channel (5-6, 7-8, 9-10, or 11-12). If that’s your choice, don’t ever engage the MUTE/ALT 3-4 switch on that stereo channel, or you’ll have every dog in the neighborhood howling at your feedback loop.
Another benefit of the ALT 3-4 feature is that it can act as an “AFL” (After Fader Listen). Just engage a channel’s MUTE/ALT 3-4 switch and the ALT 3-4 switch in the SOURCE matrix (20) and you’ll get that channel, all by itself, in the CONTROL ROOM (48) and PHONES (42).
MUTE/ALT 3-4 is one of those features that can bewilder newcomers, so take your time and play around with it. Once you’ve got it down, you’ll probably think of a hundred uses for it!
17. Channel Fader
The fader controls the channel’s level…from off to unity gain at the “U” marking, on up to 10 dB of additional gain.
“U” Like Unity Gain
Mackie mixers have a “U” symbol on
almost every level control. This “U”
stands for “unity gain,” meaning no change in signal level. Once you have
adjusted the input signal to line-level, you can set every control at “U” and your signals will travel through the mixer at optimal levels. What’s more, all the labels on our level controls are measured in decibels (dB), so you’ll know what you’re doing level-wise if you choose to change a control’s settings.
18. Signal Level LEDs
These LEDs indicate the channel ’s signal level after the GAIN and EQ controls, but just prior to the channel’s fader. So even if the fader is turned down, you can see if a signal is present.
If you’ve followed the “Set the Levels” procedure, the –20 and 0 LEDs should light frequently, the +10 LED should light occasion- ally, and the OL (Overload) LED should not light at all. If the OL LED is blinking frequently, the signal is probably distorted from overdriving the input. Either turn down the GAIN control or turn down the signal at its source.
19. SOLO Switch
This handy switch allows you to hear signals through your headphones or control room outputs without having to route them to the MAIN or ALT 3-4 mixes. Folks use solo in live work to preview channels before they are let into the mix, or just to check out what a particular channel is up to anytime during a session. You can solo as many channels at a time as you like.
Soloed channels are sent to the SOURCE mix, which ultimately feeds your CONTROL ROOM, PHONES, and Meters. Whenever SOLO is engaged, all SOURCE
(20)selections (MAIN MIX, ALT 3-4, TAPE, and FIREWIRE) are defeated, to allow the soloed signal to do just that—solo!
Note: The solo signal is pre- fader, so you can hear it even when the channel’s fader is turned down.
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