dca and vcas

[EBS_freak]

Could somebody explain these in more detail?

They seem to be a group but without audio - more a master control for a group of channels?

Edited December 18, 2012 by EBS_freak

[Monckyman]

Correct.
VCA=Voltage controlled amp (analogue desk)
DCA=Digitally controlled amp(digital desk)
Unlike a subgroup, where actual audio is routed through another gain stage,which adds noise and the possibility of clipping, VCAs only [i]control[/i] the output from whatever is assigned to them. Like a virtual fader in Cubase etc.
You can have a single VCA control a group of channels routed to stereo and panned,whereas with a subgroup you would have to use a stereo pair.
Other than that they work in exactly the same way,to control say all the BVs on one fader or percussion mics or backing tracks etc.
Increasing the VCA level will add level to all the tracks assigned to it, whilst leaving them mixed relative to each other.
Also useful for multi muting certain groups of tracks you know won`t be used in some songs.
Set them up to suit the band/and or your working style.

This link has lots of useful info.
[url="http://churchtecharts.org/home/2008/9/19/groups-vcas-and-dcas-part-two.html"]http://churchtecharts.org/home/2008/9/19/groups-vcas-and-dcas-part-two.html[/url]
MM

Edited December 18, 2012 by Monckyman

[xgsjx]

What, like a dance group?


I'm not sure if you're referring to the same thing, but the only way I know of DCAs & VCAs is through synth architecture.
Is it to this you're referring?

[51m0n]

Excellent [url="http://en.wikipedia.org/wiki/Variable-gain_amplifier"]desciption of VCA here [/url]in the In Sound Mixing Consoles section.

Cant be bothered to paraphrase it here - bit busy right now....

Dayummmm you guys are quick!

Edited December 18, 2012 by 51m0n

[EBS_freak]

So when would you use a group over a DCA/VCA? I'm thinking for monitor mixes? Say over Aviom? Or an output to another room?

And could somebody clarify my understaning of a Matrix mix?

Edited December 18, 2012 by EBS_freak

[Monckyman]

1/I would use a Group, when I wanted to interfere with the sound of stuff in that group.
I.E: send all the backing vox to a stereo group and insert a stereo compressor on it.
A group/buss, is an AUDIO path, a stage that you route channels to, and then you send the group where you like.
Usually back to the L+R, or to a tape input or another room in the club or...

A VCA isn`t an audio stage,just a controller. You can`t strap a compressor or a gate on it, as it isn`t audio.

A Matrix out is similar to a Group, in that you can rout or send any or all chans to it in a mix, but common use tends to be for delay speakers in a live situation,or infills on a wide stage or another room in a club where you need to adjust the volume to suit.
Some people rig their subs up to a Matrix so they can adjust the balance to the rest of the rig on the desk rather than their x over.
Basically it`s a separate submix that can be used for many uses that doesn`t tend to have the bells and whistles of a Group.

I think you may be confusing a Group bus with an Output bus, in that you rout inputs to a Group bus,(and the amount sent is dependent on fader position=post fade) but you SEND inputs to an Output or Mix bus(via pots that allow an independent PRE-fader position)

Make any sense or am I just making it worse?

[51m0n]

Another difference IIRC is that with a VCA if you drop the level of the VCA you also drop the level of all the sends associated with the channels associated with it it.

If you drop the level of a group then the sends on the individual tracks dotn drop and you (for instance) are left with just the reverbs of those tracks. The wet balance off the auxes is not controlled by the group fader. Which can be a right PITA!

Is that right Monckyman?

I don't have much call for them mixing ITB all the time I tend to create subfolders with extra channels within the tracks for the aux sends, which works how I want but takes a lot of time (bah humbug)