Rupert Neve 543 - 500 Series Mono Compressor-Limiter - Manual (Page 5)

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Inevitably our data bank of “natural” sound is built up on the basis of our personal experience and
this must surely emphasize the importance of listening to “natural” sound, and high quality musical
instruments within acoustic environments that is subjectively pleasing so as to develop keen awareness
that will contribute to a reliable data bank. Humans who have not experienced enough “natural”
sound may well have a flawed data bank! Quality recording equipment should be capable of retaining
“natural” sound and this is indeed the traditional measuring stick. And “creative” musical equipment
should provide the tools to manipulate the sound to enhance the emotional appeal of the music without
destroying it. Memory and knowledge of real acoustic and musical events may be the biggest tool and
advantage any recording engineer may possess.
One needs to be very careful when one hears traces of distortion prior to recording because some flavors
of distortion that might seem acceptable (or even stylish) initially, may later prove to cause irreparable
damage to parts of the sound (for example, “warm lows” but “harsh sibilance”) or in louder or quieter
sections of the recording. Experience shows that mic preamps and basic console routing paths should
offer supreme fidelity otherwise the engineer has little control or choice of recorded “color” and little
recourse to undo after the fact. Devices or circuits that can easily be bypassed are usually better choices
when “color” is a consideration and this particularly is an area where one might consider comparing
several such devices. Beware that usually deviations from linearity carry at least as much long-term
penalty as initial appeal, and that one should always be listening critically when recording and generally
“playing it safe” when introducing effects that cannot be removed.
1. Tsutomu Oohashi, Emi Nishina, Norie Kawai, Yoshitaka Fuwamoto, and Hishi Imai. National
Institute of Multimedia Education, Tokyo. “High Frequency Sound Above the Audible Range,Affects Brain Electric Activity and
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)
543 DESCRIPTION
The Portico 543 Mono Compressor delivers the unobtrusive, musical-sounding dynamic control and
brick-wall limiting made famous in the Portico 5043 to the 500 series format. The 543 features a fully
controllable compressor-limiter with feed-forward / feedback modes, Peak / RMS detection and a built
in side chain high pass filter. With an unrivaled heritage and a tremendous feature set, the 543 yields a
combination of rich warmth, flexibility and precision that allows it to be used effectively on virtually any
source material.
THE WAY THE 543 WORKS
A part of the audio signal is rectified and smoothed to produce a suitable control voltage for the V.C.A.
which has to respond very quickly and have low distortion. If the response is too fast, low frequency
signals will themselves, be “gain controlled”! If the response is too slow, the signal will overshoot
and the first few cycles will not get compressed. The speed and accuracy of the response, known as
the “attack”, and the time frame that gain remains under the initial control, known as “release” or
“recovery”, play a large part in the way a compressor sounds.
The Portico™ 543 makes use of a very accurate, low noise, low distortion V.C.A. having, essentially, no