Universal Audio UAD Plug-Ins ver.7.5 - Manual (Page 269)

UAD Powered Plug-Ins Manual - 269 - Chapter 27: Neve 33609 Compressor
Headroom Background
The hardware Neve 33609 can accept an analog signal level of approxi-
mately +26 dBu before undesirable signal clipping occurs. As the signal in-
creases up to this point however, desirable audio-path nonlinearities and
“good” harmonic distortion characteristics occur. This musically pleasing
“warmth” at higher levels is what gives the unit much of its revered sonic char-
acter. Because analog mixing consoles can typically output high signal levels,
audio engineers often take advantage of the ability to “push” the hardware
33609 into the colorful arena.
This complete pallet of sonic nuance, including the dynamic input response,
is captured in the UAD Neve 33609 model. The plug-in is calibrated inter-
nally so that 0 dBFS at its input is equivalent to an input level of approximately
+26 dBu on the 33609 hardware, where the coloring is more prominent. The
result is that a typical signal within a DAW will drive the UAD Neve 33609
into these “virtual” higher levels, resulting in fairly high amounts gain reduc-
tion.
Headroom Switch
The Headroom switch is provided to accommodate applications where high
amounts of gain reduction are not desired. Headroom simply lowers the in-
ternal operating level so that the plug-in is not “pushed” into gain reduction as
much.
Headroom can be set to 22 dB, 18 dB, or 14 dB. At 22 dB, signals will push
the plug-in into gain reduction (and more non-linearity and “good” harmonic
distortion) more easily. Set the switch to a lower value when less gain reduc-
tion and color is desired.
The numbers on the switch indicate where 0 dBFS falls relative to nominal +4
dBu. For example, with 22 dB of headroom, 0 dBFS corresponds to +4 dBu
+ 22 dB = 26 dBu. With 18 dB of headroom, 0 dBFS corresponds to +4 dBu
+ 18 dB = 22 dBu. The headroom selected will cause the plug-in to behave
as though it were a hardware 33609 connected to a nominal +4 dBu inter-
face with the selected amount of headroom. Industry standards for most DAW
interfaces are +14 dB and +18 dB headroom. The +22 dB setting approxi-
mates some analog mixing environments, and allows the entire useful dy-
namic range of the 33609 to be exercised.
The following settings are application guidelines for the Headroom switch: