User Manual

4.3.1.2. Detection Mode
The Detection Mode selection control appears only when the plug-in is inserted in a stereo
track/bus. When inserted in mono tracks, Comp VCA-65 doesn't show these controls (since
they cannot operate with mono signals).
This is where things start to really become "advanced" in the Advanced Side-Chain section.
When we described the Signal Flow [p.9] of the unit, we mentioned that the first operation
performed is encoding the audio signal in Mid/Side mode. This would seem strange,
considering that none of the standard controls in the Comp VCA-65 was ready to use a M/S
signal.
Well, here lies the reason for that Mid/Side encoding, and where we can take advantage
of it. Mid/Side mode [p.26] is a special audio encoding mode where the Mid channel is the
center of a stereo image, while the Side channel is the edges of that same image.
In this advanced Detection Mode we have three options for Stereo (Left/Right) mode, and
four other options for Mid/Side mode - now you can see why this is really "advanced". For
Stereo (Left/Right) we have Linked, Dual, and Reversed options. For Mid/Side, we have Side
to Mid, Mid to Side, Side Only, and Mid Only options.
The default option is Linked (Left/Right mode). This works with the Stereo Left/Right signal,
and detection is performed using the max level between both channels, applying the same
compression to both channels. This is the standard way and how a compressor should be
used when dealing with stereo signals.
Next option is Dual. In this option, the Stereo signal is treated as dual mono channels.
Detection is performed independently in Left and Right channels and compression is applied
accordingly to each channel also. This may be good to balance the volume between the two
channels, when they are very different, but may affect perceived channel separation.
Reversed. Again, both channels are treated independently (dual mono) for detection and
compression. However, this time compression is applied to the channel opposite to the one
where detection is performed. Therefore, Left channel detection will trigger Right channel
compression and vice-versa. Again, this may be useful to balance the mix between two
channels which are very different, but this time allowing panned elements to “answer” to
each other.
Mid/Side mode has four options. Mid Only is the first one. Detection and compression will be
performed only on the Mid Channel. This may be useful to increase the width and presence
of sided elements, like the room ambiance of drum overhead tracks (because the side
elements will be left alone).
Side Only is the next option. In this one, only the Side Channel is used for detection
and compression. This will have the opposite effect of the previous option, increasing the
presence of the centered elements of the mix (making it more mono compatible).
Comp VCA-65 Advanced Side-Chain Control Section (as it
appears in stereo tracks)
Arturia - User Manual Comp VCA-65 - COMP VCA-65 CONTROL PANEL 25