Universal Audio UAD POWERED PLUG-INS ver.6.1 - Manual (Page 324)

UAD Powered Plug-Ins Manual - 324 - Chapter 30: Manley Massive Passive EQ
Gain has a fair amount of interaction with the Bandwidth control. The maxi-
mum band gain is available in Shelf mode when Bandwidth is fully
counter-clockwise; less band gain is available in Shelf mode as the Band-
width is decreased (rotated clockwise). Conversely, the maximum gain is
available in Bell mode when Bandwidth is fully clockwise; in Bell mode less
band gain is available as Bandwidth is decreased (rotated counter-clock-
wise).
Due to the parallel EQ topology, the four band Gain controls also interact
with each other unlike typical EQs. For example, if two bands in the same
channel are boosted 20 dB at 2.7kHz, you’ll get much less than 40 dB of
boost at 2.7kHz. This also implies that if you first boost one band, that the
next three will not seem to do anything if they are at similar frequencies and
bandwidths.
Bandwidth Bandwidth adjusts the slope or “Q” of the band filter in both
Bell and Shelf modes. Bandwidth does not have a lot of range
and it also affects the maximum boost and cut (like a Pultec).
The widest Q (which is obtained at maximum boost or cut) is approximately
1 for the 22–1K (leftmost) band, and 1.5 for the other three bands. The nar-
rowest Q is approximately 2.5 to 3 for all of the bands.
Bell Mode
In Bell mode, rotating the control counter-clockwise increases the bandwidth
(lowers the Q) of the band and a broader range frequencies is affected. As
Bandwidth is rotated clockwise, bandwidth is decreased (Q is increased) and
a narrower range of frequencies is affected.
At the narrowest settings (Bandwidth fully clockwise), the maximum boost/cut
gain of 20 dB is available. As Bandwidth is broadened, the available band
gain is decreased, down to about 6 dB of boost/cut at the widest (fully
counter-clockwise) settings. The effect of the Bandwidth control in Shelf mode
is shown in
Figure 107 on page 325 .
Shelf Mode
In Shelf mode, rotating Bandwidth counter-clockwise decreases the slope of
the shelf and Gain adjustments are more gentle. As Bandwidth is rotated
clockwise, the shelf slope steepens, and Gain changes will be more obvious.