User Manual

UAD Powered Plug-Ins Manual - 127 - Fairchild 670
Fairchild Modes
Dual Left/Right In Dual L/R mode, the Fairchild operates as two monophonic compressors
with completely independent controls for the left and right channels. There is
no interaction between the left and right channels.
Lateral –
Vertical
In Lat/Vert mode, the 670 acts on the lateral and vertical (the sum and differ-
ence) components of the two stereo channels. This is accomplished by first
bringing the two stereo channels through a matrixing network which divides
them into their respective lateral and vertical components, limiting these lat-
eral and vertical components, then recombining them through a second ma-
trixing network into the left and right channels again.
The L+R (mono) signal is sent to one compressor, and the L-R (stereo) signal is
sent to the other. The two compressors work independently of each other, and
after compression the L and R signals are recovered once again by sum and
difference. This mode was created for use in mastering records, where the
mono and stereo components of the signal are encoded in this way. It also
has application for psychoacoustic processing, since the stereo panning will
change dynamically in this mode.
Lat/Vert processing provides maximum usable level and efficient use of avail-
able groove space in phonograph mastering. This results in higher volume re-
cordings with longer playing times.
Note: The terms lateral (side-to-side) and vertical (up-and-down) refer to the
mechanical modulations in a vinyl record groove that are transduced into
electrical audio signals by the phonograph stylus and cartridge.
Stereo, coupled
left/right
In this mode, the left channel is fed to one compressor, and the right channel
is fed to the other. The two compressors are constrained so that they both com-
press 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 com-
pression will be similar to the amount of compression for a transient which ap-
pears on both channels at the same time. Also, the attack and release times
for the two compressors will be the same, and attack and release behavior
will be the average of the settings for the two channels. Mono transients
should have an effective attack time of about one half the attack time for tran-
sients on only one of the two channels.