Re: X32 Discussion
Hello, I'm from Chile South America, I have two weeks ago my X32 EXELENTE machine.
the first thing I will add is regarding the VCA, quoted from one of my teachers, Mr. MAGU
VCA: An amplifier whose gain is adjusted or controlled by applying voltage (DC) external. One of the most common uses of the VCAs is on synthesizers used in electronic music, where it is used to generate the envelope of the signals generated. They are also used in compressors, limiters and companders.
The Audio Dictionary (GLENN D. WHITE) University of Washington Press.
VCA: An electronic circuit consisting of three terminals: input, output and control. The output voltage is a function of the input voltage and the control port. The stage gain (amplification) is determined by the control signal voltage which is generally DC (Direct Current or continuous), but can be any signal or digital code. Usually the main element in dynamic drivers as compressors, expanders, limiters and noise gates.
Rane Professional Audio Reference.
AC: It is used in console automation to replace manual movements of faders and knobs during mixing. Digital information from a computer (PC) controls the amount of attenuation in the signal path.
Sound Studio Production Techniques (DENNIS N. NARDANTONIO) TAB books
VCA: Unlike traditional amplifiers, where the output level is directly proportional to the level that occurs in its entry in the VCA level audio program is a function of DC voltage (usually in the range of 0 to 5 volts) applied to the control input of the device. The amount of voltage applied to the control input determines the amount of attenuation applied to the circuit output.
Modern Recording Techniques (Hubber AND RUSTEIN) SAMS
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Therefore, while the audio signal is "AC voltage" (alternating current), the voltage applied to the control input of the VCA circuit is "DC voltage" (direct current).
It is very important to understand that in any way is NOT the same move "faders" VCA that "faders" audio subgroup.
By using the motion audio subgroups of "fader" audio subgroup amplifier circuit is after the addition of all channels assigned to the subgroup.
By moving utilzar VCA faders VCA LEVEL CHANGES "FADER" INPUT CHANNEL but does not move "FADER" physically. That is, the VCA is a virtual driver input channel faders. If the mixer had "faders" motorized input channels, then that is an adjustment to a "fader" VCA would move all the "faders" input channel associated with the VCA.
So while making adjustments to the "faders" audio subgroup has no effect on the "faders" individual channel to make adjustments to the "faders" VCA has effect on all channel faders individual associated the VCA.
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Group Therapy
Article by Steve La Cerra, EQ LIVE, December 2001
Groups versus audio VCAs
The concepts of subgroup faders and VCA groups seem to be a constant source of confusion for many sound technicians. We will look at the differences and applications of each.
Audio Subgroups
The audio subgroup faders provide a path for audio input channel to the mix bus L / R. Usually, a channel mixture reaches the bus allocation using a button called "L / R". Pressing this button appears directly in the channel mixing L / R. We have all mixed in this way, always coming to the same problem: When we want a channel group sound a little more or less strong, we have to move a number of faders while trying to maintain balance thereof together with the greater accurately as possible. It is not an easy operation.
Audio subgroups alleviate this problem. Besides the assign button to "L / R" on each input channel, many tables have additional buttons allocation for "1/2", "3/4", etc., And the corresponding group faders game. Pressing "1/2" on a channel, that channel is sent to the audio subgroups 1 and 2 (the channel pan knob moves the signal between them). Assigning all channels of a large battery to a subset of audio, you can make the whole drum kit sounds stronger or weaker maintaining the balance between the different microphones, using a single fader.
Usually a subgroup fader will control bread, button mapping L / R, a mute switch, and an insertion point. You must assign the subgroup L / R or not hear any of the channels in that group. Subgroups are "panoramizables", as a channel, so that almost always need two subgroups to create a stereo. (There are some tables that have a single fader for stereo subgroup, but few.) Of course, you can assign a complete drum kit to a subgroup, in which case the battery will be heard in mono. One subgroup surely be more appropriate for a multichannel signal low.
If you create a number of subgroups for drums, bass, guitars, keyboards, vocals, and effects provides more control over signals with less fingers also facilitates silencing "mute" many channels with fewer button presses ( purposes for example). Note that a channel may be assigned to a subgroup and the mixing L / R time. This is something to be controlled, as it decreases the effectiveness of the subgroups.
I'm running out compressors ...
Audio subgroups are very useful when you have limited external teams: What do we do if we have four channels choral voices and a single compressor? Assigning all channels to a single subgroup chorus audio and connecting the compressor in the insertion of audio subgroup mics all voices are compressed and now under the control of a single fader (not bad!). Some technicians do, when there are plenty of tom mics and not enough gates. Assign toms a couple of stereo audio subgroups, and insert the doors in the subgroups. Now all toms use a door inserted into the two channels - but be careful to adjust the doors to not cut any of the strokes tom of small drums.
VCA Groups
A VCA group fader no audio circuitry to the mixture, is literally a remote control of a channel fader (this is the major point of confusion regarding the VCAs). Tables with VCAs usually have two independent sets of buttons for channel allocation: one selects the audio circuit and the other selected for remote VCA. After assigning a channel to a VCA, the channel must be assigned to a circuit audio or no sound is heard. VCA group faders have no pan control, and you can not pan a VCA-controlled channel is panned by the VCA. Most tables have direct output jacks on the rear panel audio for each subgroup (to, for example, connect to a multitrack recorder), but never have outlets for VCA groups.
The VCAs can reduce the mixture to a still smaller number of faders. That drum kit 10-channel stereo can be controlled with a VCA fader. The same is true of a set of multichannel stereo keyboards. It makes possible a "remote control" complex with multiple input channels VCAs (audio ineffective in subgroups). For example some technicians independent VCA groups create drums, bass, guitars, and keyboards, and then also all those channels assigned to a VCA fader further; This additional VCA serves as a global control for the whole group minus the vocals. The VCAs work with a "lowest common denominator" so if you have the VCA fader "group" muted or lowered to a minimum, nothing will be heard regardless of the position of the other VCA faders.
I'm losing my balance ...
There are times when audio subgroups do not solve the problem. Take for instance that we have two independent audio subgroups effects voices. Assume that are post-fader effects sends. Moving a vocal channel fader up or down, the level of reverberation of voices changes with fader - keeping the balance between direct and reverberation. Correct. But if the voice group move up or down, the level of the reverb will not change - changing the balance between direct and reverberation. Even when the subgroup of voices silenced, they will still hear the reverb. You can assign the voices and effects to the same subgroup, but then you will not have an easy way to mute effects between songs when he / singer makes his "schtick".
The solution here is VCA groups. By assigning a voice channel and a VCA VCA move up or down, you are controlling remotely-channel fader so that the auxiliary send levels to also change. If voice channels are assigned to a VCA group, moving the VCA fader levels change choral voices and - due to the effect of remote control - will also change simultaneously levels effect sends chorus of voices . Now, we are controlling voices multichannel effects using a single fader.
A good trick to try is to assign the battery channel audio to subgroups 1 and 2, and connect a stereo compressor group inserts. Assign channels to VCA kick and snare 1, and the rest of the kit to VCA2. Moving and VCA2 VCA1 levels are balanced kick / snare the rest of the kit. Raising or lowering the subgroup faders 1 and 2 just get the whole kit sound more or less. But what is interesting is that as you raise the faders over VCA-send signal to the compressor because the channel levels to audio subgroups 1 and 2 are controlled remotely - by VCAs. Changing these levels the compressor reacts differently. You can control the amount of compression needed using VCAs and then adjust the overall level of the kit using the audio subgroup faders.
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Mauricio Ramirez
Meyer Sound Seminars and Trainings
Atte: Claudio Luis Pardo Contreras
Sound Technican.
Sound reinforcement system design.
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