MIXER ANATOMY: CHAPTER 2

Bus/Subgroup Outputs

In 4- and 8-Bus consoles, the output of the PAN control can be assigned to subgroup busses. The ASSIGN switches (1-2, 3-4, L-R) direct the channel output to pairs of busses. The subgroup bus outputs appear on the balanced 1/4" TRS SUB OUT jacks.

The subgroup outputs can be used to feed a mix of several channels (for example six mics on a drum kit) to a single pair of recorder tracks.

Bus Output Levels

PAN

L R

1

MUTE

OL

-20

SOLO

1–2

3–4

L - R

OO

pan fully right.

The 8-Bus console extends this trick by tripling the outputs of each of the eight busses to accommodate a 24-track recorder.

On most Mackie mixers, subgroup busses can be routed to the main outputs so that all channels assigned to that subgroup can be controlled by a single fader, retaining the balance and pan position set by the channel controls. You can individually mic each of the background singers, assign their channels

to a single subgroup or pair, and use the subgroup fader(s) to bring the background vocals up in the mix when they’re needed.

Not all models have the same SUB outputs, level

The subgroup bus output level on all

of the Mackie mixers is nominally 0 dBu. The output level of the busses is controlled by the bus faders.

On the 8-Bus console, the bus output level is switch-selectable between +4 dBu and –10 dBV, allowing you to properly match pro or semi-pro record- ers.

6

5

4

3

 

IN –10dBV

 

 

 

OUT +4dBu

 

 

14

OPERATING

12

11

13 LEVEL

22

21

20

19

 

+4dBu BALANCED / –10dBV UNBALANCED

 

 

SUBMASTER / TAPE OUTPUTS

Double (and triple) Bussing

The bus outputs on the 1642-VLZ PRO,

SR, and 8-Bus mixers have duplicate jacks to make connection to a multitrack

recorder easier. Even though the SR and 1642 are four-bus mixers with four subgroups, they have eight SUB OUT jacks for feeding eight recorder tracks, thanks to a trick called Double Bussing.

SUB OUTS 1 and 5 carry the same signal, as do 2 and 6, 3 and 7, and 4 and 8. By connecting those eight jacks to the eight inputs of your recorder, you can route any input channel to any track.

To record onto Track 1, assign the input channel to Bus 1 by pressing the 1-2 ASSIGN button and turning the PAN control fully left. On the recorder, put Track 1 into the Record mode, being sure that Track 5 is in the Safe or Play mode. To record on Track 5, use the same bus assignment on the mixer, but put Track 5 in Record. To record on Track 2 or 6, ASSIGN to 1-2 and

 

 

 

 

22

Compact Mixer Reference Guide

 

 

 

controls, and routing capabilities. Input channels on the CFX series cannot be routed directly to the MAIN outputs, but must first be routed to a pair of subgroup busses, which are in turn assigned to the MAIN outputs by switches in the mixer’s Subgroup section. The PPM series has no SUB outputs since it has no subgroups.

ALT 3-4 Outputs

The dual-purpose MUTE/ALT 3-4 switch on the 1202/1402-VLZ PRO and Onyx 1220/1620 mixers is a variation on the subgroup concept. When Greg Mackie was designing our first compact mixer, he wanted to include a mute switch for each channel. Mute switches do just what they say — turn off the signal by sending it into oblivion. “Gee, what a waste,” Greg reasoned. “Why not have the mute button route the signal somewhere else useful - like an alternate stereo bus?”

So MUTE/ALT 3-4 really serves two purposes: muting (handy during a mixdown session or live show) and signal routing. For multitrack recording and live mixing, it serves as an extra stereo bus.

One difference between the ALT 3-4 outputs and BUS OUTs 3 and 4 on the larger consoles is that there’s no output level control for those busses

–they run at unity gain. Another difference is that it’s either/or routing – a channel can’t be assigned to both the MAIN and ALT outputs simultaneously. But like the true 4-bus consoles, the ALT busses can be routed to the MAIN outputs, serving as a submaster pair.

To MUTE channels in the main mix, leave the ALT 3-4 outputs disconnected. Pressing the MUTE/ALT 3-4 button switches the channel signal from the MAIN to the ALT 3-4 busses, sending it off to never- never land, disconnecting it from the MAIN MIX, and