Universal Audio UAD Plug-Ins ver.7.5 - Manual (Page 268)

UAD Powered Plug-Ins Manual - 268 - Chapter 27: Neve 33609 Compressor
Stereo
In stereo mode, the left channel is fed to the channel one compressor, and the
right channel is fed to the channel two compressor. The two compressors are
constrained so that they both compress the same amount at any instant. This
prevents transients which appear only on one channel from shifting the image
of the output. Any big transient on either channel will cause both channels to
compress. The amount of compression will be similar to the amount of com-
pression for a transient which appears on both channels at the same time.
In stereo operation the controls for channels 1 and 2 are independent and
can be set separately. Generally, the channel with the “most processing oc-
curring” controls the processing for the other channel. For example, if the
same signal is fed to both channels in stereo mode and channel 1 has a lower
threshold setting than channel 2, the channel 1 threshold value is used for
both channels. Similarly, if channel 1 were disabled (using “In” switches),
channel 2 settings would be used because “more processing” occurs with the
channel 2 settings. It's not always so simple though, as in the following cases:
• If you feed the same signal into both channels, you can have a lower thresh-
old with a lower ratio on one channel, and a higher threshold with a higher
ratio on the other channel. In this case, you will get a double knee, with the
lower ratio being used between the knees, and the higher ratio above both
knees.
• If you feed the same signal into both channels, you can have a lower thresh-
old with a faster release on one channel, and a higher threshold with a
slower release in the other channel. In this case, you will get a two-stage re-
lease after a transient, with the first channel releasing at the fast rate until
you get down to where the other one is; then the release will continue at the
slower rate.
Expert Question
Is there any reason I would want to use stereo mode and still have the settings
for the two channels different?
Yes. Linking the sidechains simply prevents left-right image shifting. Threshold,
attack, and recovery can be set independently to cause the compressor to be
more sensitive to instruments which are panned to one side or the other. Out-
put controls can be set separately in order to correct an overall image shift at
the output.