Re: Groups vs. Mix Buses - long and winding road
I'm reading through section 5.9 of the X32's user manual and I'm wondering if I am understanding correctly.
Would it be correct to say that a sub-group (as implemented in the X32) is the same as a post-fader mix bus with the each channel's send level set to unity?
If so, why use a sub-group when
a) it still uses one of your available 16 mix buses,
b) you no longer have the *option* to control each level separate from the fader (i.e. the send level is strictly controlled by the fader; not the aux-send controls), and
c) you lose the *option* to send to the bus pre-fader (since according to the docs, the level follows the fader)?
Based on only those observations, it would seem a sub-group is just a post-fader mix bus with aux-sends set to unity.
I'm guessing I'm missing something. Most likely obvious.
In addition to Brian's comments, consider that the subgroups allow you to perform processing on the summed audio of all the channels assigned to the subgroup. Here's a hypothetical example using vocal compression, and we'll assume that the console is being used for FOH only - no monitors or multi track recording.
On your vox inputs, use the channel strip's compressor to get the result you want for each singer. Assign the channels to a subgroup and NOT L/R. Insert a compressor (if it doesn't have one as part of the subgroup) and assign the subgroup to L/R. Bring up the background vocals and adjust the compressor so they just tickle the first gain reduction light (usually -1 or -2 dB) and then raise the threshold until it stops. Bring up your lead vocal and use it to actually 'hit' the compressor. It won't have to be much, or it could be a lot; that's an artistic decision you get to make... but this will help you keep a "space" between the lead and BGV. Another dynamics example are in the drum kit. The "arena rock" drum sound from the 1980s and 1990s came from lots of compression, reverb and some radical channel EQ... if the drum channels are assigned to L/R, also assign the toms to a pair of (or a stereo) subgroup to preserve any panning. The subgroup(s) get inserted compressors and are assigned back to L/R. Adjust compressor to give the kit a "bigger than life" presence. When the effect is not needed, you bring down the subgroup masters and bring them up when you do. Note that this is a Ye Olde Analogue Tricke and many digital mixers DO NOT compensate for the additional processing latency from the subgroup compressor. This creates an audible and generally unpleasant comb filtering. I don't know if the X32 has compensation, but the feature is important if you do anything where the same signal is routed to multiple buses, separately processed and then recombined. Almost-light speed analog doesn't present an audible problem but you'll sure hear it in digi-land.
An example of grouping for EQ reasons in youth theater... this is a "stock" design I use at the local PAC. Three AT853 hanging choir mics about mid-stage, for upstage ensemble pick up; 3 Crown PCC-160 across the apron (the back side lobe picks up the orchestra pit), 12-16 wireless body packs on the cast, keyboards and "spot" mics in the pit. The hangers, foot mics, and pit each get assigned to individual subgroups; cast wireless get at least 2 groups (men/women, or some such) and each subgroup gets an inserted parametric EQ. I "ring" each hanging mic gently to see if there are common feedback frequencies BEFORE I bring them up together... I use just a little channel strip EQ to help them sound the same, then use the subgroup parametric to get as much gain before feedback as I can. This allows the use of the input strip EQ to voice the individual mics. Lather, rinse and repeat for the foot mics, and the wireless stuff. Before any of this is done, however, I've done my system work so I'm not having to fight the PA at the input strip level... and that's a whole 'nuther post that isn't specific to the X32. At any rate, the outputs of the subgroups are routed where ever the need to go... L/R, matrix, etc and there is no "parallel processing" involved. With enough time it's possible to make 3rd graders audible to grandma in the back row.
In general it's a good idea to consider your routing based on the result you want and work your way backwards through the signal chain.
