ghetto subgroup! do i have this right?...
vocal channels uncomp'ed, with their auxes set pre-fader and their main fader levels off;
run a 1/4" TRS to XLR jumper cable from say aux 5 out to an open "vocal group" channel;
compress that channel, and send it on out to the mains!
i guess you'd have to then use the aux 5 mixer screen as a "vocals layer" to control individual levels, right?
the idea of having to go through a whole 'nother round of D-A then A-D conversion for the all-important vocals doesn't thrill me, though.
Yes, walterw, I believe you have the general idea. Here's a more specific example for those who might be interested that want to follow along:
3 vocal mics, with 3 vocal monitor mixes (1 for each vocalist, Aux 1, 2, 3), and the "ghetto" vocal submix (aux 5) being "returned" to input channel 16:
Main inputs, faders all the way down:
Ch1 vocal: uncompressed (send to Aux 1 monitor mix, and Aux 5 submix, both pre fader)
Ch2 vocal: uncompressed (send to Aux 2 monitor mix, and Aux 5 submix, both pre fader)
Ch3 vocal: uncompressed (send to Aux 3 monitor mix, and Aux 5 submix, both pre fader)
- Aux 1,2,3 monitor feeds operate as typical
- Aux 5 (vox submix): set nominal output levels for all 3 vocal channels, and run a physical connection from Aux5 out to Channel 16 input (or any channel you want) using a 1/4" to 1/4" cable.
[note: make sure that Ch16 is not feeding any signal to Aux5 as this would create a nasty feedback loop!!!] Compress/EQ ch 16 to taste and use its fader to feed the main output mix. Aux 5 can be used for "active mixing" of the individual vocal channels if needed, rather than "set and forget". This allows you to have uncompressed vocal channels for stage monitor wedges, but allows compression of vocals to the main output for FOH.
Now a couple of nuances and caveats to this:
Yes, there is an added layer of D/A A/D conversion, but I'm of the thinking that this technology has progressed to the point where it is moot for most general live sound applications.
The Reverb and Delay auxes do NOT have the ability to switch to PRE fader (IIRC). Thus, if you want echo or reverb on the vocals, you'll have to apply them globally to the vocal submix channel return (ch 16 in my example). Depending on your needs, this may or may not matter for much.
An interesting technique that can be used as an alternative to Aux 5 "active mixing" of the vocal channels is this: use the uncompressed vocal channels 1,2,3 (on the Main screen) to actively mix vocal levels (if for example, all 3 vocalists take turns singing lead). Set the "submix" channel 16 to provide a "nominal" level for all of the vocalists, but then bump the lead vocalist's INPUT CHANNEL FADER (1,2 or 3) as needed to provide the extra vocal to punch them to the front of the vocal mix. (The assumption has to be made that the vocalists are not wildly out of control, screaming, or doing other nasty things that cause problems with dynamics - IOW, they use proper vocal mic technique). With this technique, you get some of the clarity and articulation of the non-compressed vocal channel, but with the benefits of compression provided by the submix ch 16. [note: depending on latency, this may result in phase cancellation between ch1,2,3 and Ch16, due to the physical routing of aux5 output to Ch16 input. I've not tested this to see if it is an issue or not. ]
The above can also solve the dilemma of providing appropriate SEND levels to the Reverb/Delay aux feeds. If, for example, Vocal CH1 is the lead for a song, and you bump up that channel fader +5db, this will provide enough "post fader" gain to feed the delay or reverb. Again, the ch 16 "submix" can be used for a nominal amount of overall vocal Reverb, while the echo for lead vocals can be provided by bumping up the individual Ch 1,2 or 3 faders.
Apologies for the long post. This can be a little complicated and convoluted, but in theory should work. Just take your time and be careful with each step...adjust faders slowly initially. Hope you find it interesting to experiment with!
