Rupert Neve Portico II - Master Buss Processor - Manual (Page 7)

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Sound Perception” Paper read at 91st. Convention of the A.E.S.October 1991. Section 7. (1), Conclusion.
2. Miland Kunchur,Depart of Physics and Astronomy, University of South Carolina. “Temporal resolution of hearing probed
by bandwidth restriction”, M. N. Kunchur, Acta Acustica united with Acustica 94, 594–603 (2008) (http://www.physics.
sc.edu/kunchur/Acoustics-papers.htm)
3. Miland Kunchur,Depart of Physics and Astronomy, University of South Carolina.Probing the temporal resolution and
bandwidth of human hearing , M. N. Kunchur, Proc. of Meetings on Acoustics (POMA) 2, 050006 (2008)
COMPRESSOR-LIMITER CONTROLS
THRESHOLD
Sets level where the compressor may begin to react from -30 dB to +20 dB. Minimal or no compression
is with this control fully clockwise and it gets more sensitive and tends to cause more gain reduction as
the knob is rotated counter-clockwise (which may be counter-intuitive to some).
RATIO
Sets the “slope” of the compression from 1.1:1 (minimal) to LIMIT (approximately 20:1) (or drastic). For
example if this knob is set for 3:1 then if the signal goes 15 dB over the threshold then it attenuates 10
dB and allows the output to rise 5 dB. In general, low ratios can not damage the music as much as high
ratios but high ratios may be more useful to minimize clipping and OL lights in the recorder.
Excuse the front panel jump and digression, but it is appropriate to mention the GAIN REDUCTION
and OUTPUT meters now because so many of us learned to set up compressors by watching the all-
important GR meter. When setting the Threshold and Ratio it does help to use the meters however, as
always, we should rely on our ears and ye olde “COMP IN” (Bypass Button) most of all. One might try
to interpret the OUTPUT meter as one exercises ye olde “COMP IN” button too, as this might be more
appropriate to your goals than a target of X dB or number of LEDs of compression. Is the goal to make
great sounds or to blink LEDs half way down the meter because you read it somewhere?
BLEND
This just mixes the dry or raw uncompressed signal and the compressed signal. Fully counter-clockwise
is uncompressed and is very similar to not having the “COMP IN” button pushed in. Fully clockwise is
100% compressor-limiter path, and one can “blend” or mix how much compressed-limited signal vs.
dry signal. This control is not found on vintage compressors and is a recent invention that has gained
popularity. Why? Compressors generally attenuate the louder signals and leave the quiet bits untouched,
which might be re-worded as compressors tend to reduce transient peaks. If one then mixes in some
dry signal, peaks and all, with the compressor (usually with the Threshold lowish, Ratio steepish and
“GAIN” turned up to compensate) then the “blend” will be mostly dry for the loud bits and compressor
for the quiet bits, which can likewise be re-worded to the quiet stuff became louder or the room reverb
increased. Obviously one has a fair amount more control over the entire dynamic range given this
control and it should be mentioned less likelihood of damage to parts of the music, because “blending”
implies not 100% compression electronics and there is important musical information in those transient
peaks (like the hit of drums and percussion where a lot of the groove lives).
COMP IN
The compressor-limiter section is not bypassed with this button in. This may be the most useful control
on the compressor because it is there for “confidence checks”. In particular, exercise it in both the
quietest and the loudest sections of the song. Watch out for the compressor and limiter exaggerating
noise and room sound in the quiet sections and chopping off transients and consonants in the loud