OK, I've got a dumb question. I've been reading lately and I've come across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are. To my limited understanding, the method of "grouping" certain
channels and sending that "grouped" signal to a destination other than the
MAIN output has fallen under three names. Subs, busses, and groups. Now
that VCAs have entered the mix, I'm wondering what makes them so special and
different.
-Luther in ND

A VCA allows you to control a number of channels with one fader,
irrespective of where those channels are assigned (subgroup, L/R). In the
presence of VCAs, subgroups are needed only if one wants to send a group of
channels out on a separate send, or if one wants to process a group of
channels independently (such as a compressor on the vocal group, or a
multi-band compressor on the drum group(s). Here's a good VCA primer:
http://www.allen-heath.com/DL/vca_book.pdf

"Luther Bell" wrote in message
...
OK, I've got a dumb question. I've been reading lately and I've come
across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs
or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are. To my limited understanding, the method of "grouping"
certain
channels and sending that "grouped" signal to a destination other than the
MAIN output has fallen under three names. Subs, busses, and groups. Now
that VCAs have entered the mix, I'm wondering what makes them so special
and
different.
-Luther in ND

A VCA allows you to control a number of channels with one fader,
irrespective of where those channels are assigned (subgroup, L/R). In the
presence of VCAs, subgroups are needed only if one wants to send a group of
channels out on a separate send, or if one wants to process a group of
channels independently (such as a compressor on the vocal group, or a
multi-band compressor on the drum group(s). Here's a good VCA primer:
http://www.allen-heath.com/DL/vca_book.pdf

"Luther Bell" wrote in message
...
OK, I've got a dumb question. I've been reading lately and I've come
across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs
or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are. To my limited understanding, the method of "grouping"
certain
channels and sending that "grouped" signal to a destination other than the
MAIN output has fallen under three names. Subs, busses, and groups. Now
that VCAs have entered the mix, I'm wondering what makes them so special
and
different.
-Luther in ND

Luther Bell wrote:

OK, I've got a dumb question. I've been reading lately and I've come
across a lot of mixers with either VCAs (voltage controlled
amplifiers) and subs or VCAs and groups, and I was wondering what the
difference between VCAs and the rest are. To my limited
understanding, the method of "grouping" certain channels and sending
that "grouped" signal to a destination other than the MAIN output has
fallen under three names. Subs, busses, and groups. Now that VCAs
have entered the mix, I'm wondering what makes them so special and
different.

A VCA is a Voltage Controlled Amplifier. Think of it as a slider that is
controlled by a voltage source, instead of a knob.

In consoles, VCAs are a means for controlling a number of different channels
at the same time.

Luther Bell wrote:

OK, I've got a dumb question. I've been reading lately and I've come
across a lot of mixers with either VCAs (voltage controlled
amplifiers) and subs or VCAs and groups, and I was wondering what the
difference between VCAs and the rest are. To my limited
understanding, the method of "grouping" certain channels and sending
that "grouped" signal to a destination other than the MAIN output has
fallen under three names. Subs, busses, and groups. Now that VCAs
have entered the mix, I'm wondering what makes them so special and
different.

A VCA is a Voltage Controlled Amplifier. Think of it as a slider that is
controlled by a voltage source, instead of a knob.

In consoles, VCAs are a means for controlling a number of different channels
at the same time.

"Luther Bell" wrote in message
...
OK, I've got a dumb question. I've been reading lately and I've come
across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs
or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are. To my limited understanding, the method of "grouping"
certain
channels and sending that "grouped" signal to a destination other than
the
MAIN output has fallen under three names. Subs, busses, and groups. Now
that VCAs have entered the mix, I'm wondering what makes them so special
and
different.
-Luther in ND

VCA means Voltage Cotrolled Amplifier... you'll find them in lots of things
like some (but not all) types of compressors, to noise gates, to console
channels, for example. In the case of consoles, certain types of automation
that don't use moving faders use VCA's to determine the level of each
channel. Simply speaking, in these instances, the fader for each channel
essentially serves as an input by which to program the automation computer
with regard to that channel; and then on playback, the computer controls
the VCA.

In the case of VCA groups, it's basically just a type of submix; you can
route - let's say - all your drum tracks, for example to "VCA Group 1", and
control the overall level of your drum submix with a single fader - and
even automate that separately. So let's say (sticking with the example of
drums) you want the snare to come up in the choruses; so you would automate
that move on the snare channel alone, but then there's also a quiet section
of the song where the snare balance relative to the rest of the kit is
fine, but the drums overall need to come down a bit - well then you could
do that with a single move on the VCA Group fader and not have to do moves
on each individual drum track... saves time, more convenient, etc.

As for the terms "subs, busses and groups" - with regard to audio paths &
mixing - in most cases they're interchangeable.
--


Neil Henderson
Progressive Rock
http://www.saqqararecords.com

"Luther Bell" wrote in message
...
OK, I've got a dumb question. I've been reading lately and I've come
across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs
or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are. To my limited understanding, the method of "grouping"
certain
channels and sending that "grouped" signal to a destination other than
the
MAIN output has fallen under three names. Subs, busses, and groups. Now
that VCAs have entered the mix, I'm wondering what makes them so special
and
different.
-Luther in ND

VCA means Voltage Cotrolled Amplifier... you'll find them in lots of things
like some (but not all) types of compressors, to noise gates, to console
channels, for example. In the case of consoles, certain types of automation
that don't use moving faders use VCA's to determine the level of each
channel. Simply speaking, in these instances, the fader for each channel
essentially serves as an input by which to program the automation computer
with regard to that channel; and then on playback, the computer controls
the VCA.

In the case of VCA groups, it's basically just a type of submix; you can
route - let's say - all your drum tracks, for example to "VCA Group 1", and
control the overall level of your drum submix with a single fader - and
even automate that separately. So let's say (sticking with the example of
drums) you want the snare to come up in the choruses; so you would automate
that move on the snare channel alone, but then there's also a quiet section
of the song where the snare balance relative to the rest of the kit is
fine, but the drums overall need to come down a bit - well then you could
do that with a single move on the VCA Group fader and not have to do moves
on each individual drum track... saves time, more convenient, etc.

As for the terms "subs, busses and groups" - with regard to audio paths &
mixing - in most cases they're interchangeable.
--


Neil Henderson
Progressive Rock
http://www.saqqararecords.com

In article writes:

I've come across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are.

The tradiditional signal flow in a mixer with subgroups (or
submasters) is that it works like several individual mixers, one per
subgroup. Channels which are assigned to that group get mixed and are
controlled by one "sub" fader. If it's a "submaster", that means that
the subgroup faders can be further assigned to a master bus which
mixes the subgroups to a main output. In this system, signal actually
flows through the subgroup faders or pots, and you can actually take
the output of each subgroup and use it external to the mixer. An
example would be to assign all the drums to one (or two, using
panpots) subgroups, then record the output of the "drum subs" so you
have all the drums recorded to two tracks.

With VCAs, a single fader or pot controls a DC voltage which can be
switched to any number of channel VCAs, and the attenuation or
amplification (depending on how you interpret the "A" in "VCA") of
each channel will follow the control voltage. If all of the channels
(audio) are routed to the the main bus, adjusting the control fader
changes the level of each channel together, effectively controlling
that "submix" of channels with a single control. However, unlike the
subgroups, there is not necessarily an independent output from that
group. That's an audio routing function and needs its own path.

There's no reason why audio subgroups and VCAs can't be combined, and
in fact they are in many mixers. In that case, however, often what
looks physically like the subgroup fader in a traditinal console is in
reality the VCA controller, and the channels which it control get
routed to a fixed gain (usually unity gain) mixer for the subgroup
output.



--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article writes:

I've come across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are.

The tradiditional signal flow in a mixer with subgroups (or
submasters) is that it works like several individual mixers, one per
subgroup. Channels which are assigned to that group get mixed and are
controlled by one "sub" fader. If it's a "submaster", that means that
the subgroup faders can be further assigned to a master bus which
mixes the subgroups to a main output. In this system, signal actually
flows through the subgroup faders or pots, and you can actually take
the output of each subgroup and use it external to the mixer. An
example would be to assign all the drums to one (or two, using
panpots) subgroups, then record the output of the "drum subs" so you
have all the drums recorded to two tracks.

With VCAs, a single fader or pot controls a DC voltage which can be
switched to any number of channel VCAs, and the attenuation or
amplification (depending on how you interpret the "A" in "VCA") of
each channel will follow the control voltage. If all of the channels
(audio) are routed to the the main bus, adjusting the control fader
changes the level of each channel together, effectively controlling
that "submix" of channels with a single control. However, unlike the
subgroups, there is not necessarily an independent output from that
group. That's an audio routing function and needs its own path.

There's no reason why audio subgroups and VCAs can't be combined, and
in fact they are in many mixers. In that case, however, often what
looks physically like the subgroup fader in a traditinal console is in
reality the VCA controller, and the channels which it control get
routed to a fixed gain (usually unity gain) mixer for the subgroup
output.



--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

(Mike Rivers) wrote in message news:znr1084447936k@trad...

With VCAs, a single fader or pot controls a DC voltage which can be
switched to any number of channel VCAs, and the attenuation or
amplification (depending on how you interpret the "A" in "VCA") of
each channel will follow the control voltage. If all of the channels
(audio) are routed to the the main bus, adjusting the control fader
changes the level of each channel together, effectively controlling
that "submix" of channels with a single control.

An important difference, if it's not already obvious from Mike's very
comprehensive explanation, is that faders do get assigned to Subs both
literally & in the jargon...i.e., when you "assign all the drums to
SubGroup #2" ...the audio signal from the Channel passes through the
summing amp & fader of the Sub. Whereas with a VCA, *despite* the fact
that the jargon remains consistant w/ the Subgroup paradigm (eg., "I'm
gonna assign all the drums to VCA #2"), what you are literally doing
is assigning control fader #2 to all of the individual VCAs in each
channel. It's almost the exact opposite of what we say we're doing.

(Mike Rivers) wrote in message news:znr1084447936k@trad...

With VCAs, a single fader or pot controls a DC voltage which can be
switched to any number of channel VCAs, and the attenuation or
amplification (depending on how you interpret the "A" in "VCA") of
each channel will follow the control voltage. If all of the channels
(audio) are routed to the the main bus, adjusting the control fader
changes the level of each channel together, effectively controlling
that "submix" of channels with a single control.

An important difference, if it's not already obvious from Mike's very
comprehensive explanation, is that faders do get assigned to Subs both
literally & in the jargon...i.e., when you "assign all the drums to
SubGroup #2" ...the audio signal from the Channel passes through the
summing amp & fader of the Sub. Whereas with a VCA, *despite* the fact
that the jargon remains consistant w/ the Subgroup paradigm (eg., "I'm
gonna assign all the drums to VCA #2"), what you are literally doing
is assigning control fader #2 to all of the individual VCAs in each
channel. It's almost the exact opposite of what we say we're doing.

the jargon remains consistant w/ the Subgroup paradigm (eg., "I'm
gonna assign all the drums to VCA #2"), what you are literally doing
is assigning control fader #2 to all of the individual VCAs in each
channel. It's almost the exact opposite of what we say we're doing.

Exactly..and the associated difference in the gain structure and routing is
what gives VCA mixing the power it has.


John A. Chiara
SOS Recording Studio
Live Sound Inc.
Albany, NY
www.sosrecording.net
518-449-1637

the jargon remains consistant w/ the Subgroup paradigm (eg., "I'm
gonna assign all the drums to VCA #2"), what you are literally doing
is assigning control fader #2 to all of the individual VCAs in each
channel. It's almost the exact opposite of what we say we're doing.

Exactly..and the associated difference in the gain structure and routing is
what gives VCA mixing the power it has.


John A. Chiara
SOS Recording Studio
Live Sound Inc.
Albany, NY
www.sosrecording.net
518-449-1637

In article
writes:

I've come across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are.

As everyone has stated, VCA's are voltage controlled amplifiers, this means
that instead of routing the audio signal (from an assignment switch at each
channel) directly to the sub group fader, the VCA is controlling an amplifier
(I think an op amp) at the channel you want (by switching it on from that
channel). Thus, no audio signal flows thru a VCA, but audio signal does flow
thru a regular sub group fader.
Aux's are mostly reserved for sending signals to a time based processor like
reverbs and delays, some studio guy's (like myself) will use them for headphone
sends in a tracking session.

In article
writes:

I've come across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are.

As everyone has stated, VCA's are voltage controlled amplifiers, this means
that instead of routing the audio signal (from an assignment switch at each
channel) directly to the sub group fader, the VCA is controlling an amplifier
(I think an op amp) at the channel you want (by switching it on from that
channel). Thus, no audio signal flows thru a VCA, but audio signal does flow
thru a regular sub group fader.
Aux's are mostly reserved for sending signals to a time based processor like
reverbs and delays, some studio guy's (like myself) will use them for headphone
sends in a tracking session.

In article ,
Luther Bell wrote:
OK, I've got a dumb question. I've been reading lately and I've come across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are. To my limited understanding, the method of "grouping" certain
channels and sending that "grouped" signal to a destination other than the
MAIN output has fallen under three names. Subs, busses, and groups. Now
that VCAs have entered the mix, I'm wondering what makes them so special and
different.

The biggest functional difference is in how postfade channel sends
behave. When using VCAs, moving the VCA group master fader is the
same as moving each fader in the group, so the postfade sends still
work like you think - turning down the VCA group master turns down
both the direct sound and the sound going to the postfade send.

If you instead group some channels using a summing amplifier type of
group and turn down the group master, you're not affecting the amount
sent to any of the postfade channel sends. If you're running a reverb
for example as a postfade effect and you turn a group down, then the
total effect is to turn down the direct sound and leave the wet sound
where it was (unless of course the effect return is also bused to the
same group, but that gets cumbersome unless you can dedicate a lot of
effects to each grouped set of channels and then keep it all straight
in your head).


VCAs make sense with big consoles when you want to control fader
levels more easily, and actual subgroups make sense only when you need
to submix signals together, for example to compress several channels
collectively. They're different animals, and many consoles offer both
functions.


Regards,

Monte McGuire

In article ,
Luther Bell wrote:
OK, I've got a dumb question. I've been reading lately and I've come across
a lot of mixers with either VCAs (voltage controlled amplifiers) and subs or
VCAs and groups, and I was wondering what the difference between VCAs and
the rest are. To my limited understanding, the method of "grouping" certain
channels and sending that "grouped" signal to a destination other than the
MAIN output has fallen under three names. Subs, busses, and groups. Now
that VCAs have entered the mix, I'm wondering what makes them so special and
different.

The biggest functional difference is in how postfade channel sends
behave. When using VCAs, moving the VCA group master fader is the
same as moving each fader in the group, so the postfade sends still
work like you think - turning down the VCA group master turns down
both the direct sound and the sound going to the postfade send.

If you instead group some channels using a summing amplifier type of
group and turn down the group master, you're not affecting the amount
sent to any of the postfade channel sends. If you're running a reverb
for example as a postfade effect and you turn a group down, then the
total effect is to turn down the direct sound and leave the wet sound
where it was (unless of course the effect return is also bused to the
same group, but that gets cumbersome unless you can dedicate a lot of
effects to each grouped set of channels and then keep it all straight
in your head).


VCAs make sense with big consoles when you want to control fader
levels more easily, and actual subgroups make sense only when you need
to submix signals together, for example to compress several channels
collectively. They're different animals, and many consoles offer both
functions.


Regards,

Monte McGuire