Rupert Neve Portico II - Channel - Manual (Page 17)

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compressor/limiters to introduce a nasty form of distortion called “modulation distortion” when they are
set for a combination of fast attacks, fast releases and high ratios.
FAST
This changes the compressor from essentially responding to the RMS level of the audio to also
responding to the PEAK level. RMS (root mean squared) circuits are considered to better mimic the
way the ears perceive apparent loudness, while Peak circuits tend to directly respond to the waveform
voltage which may be more of a concern for prevention of clipping and maximizing levels. In this case,
pushing FAST uses a combination of both methods to get the best of both worlds and avoidance of the
drawbacks of each method on its own.
Do we recommend any particular compressor settings for particular instruments? No, but we will
recommend that you not depend on hear-say settings and that you always listen carefully to the levels
and mix values as you tweak. You can generally regard a compressor as a semi-automatic volume
control and be aware of the kinds of artifacts that you would get moving a fader quickly. You can also
listen for changes in tone that are probably due to altering the relative strength of transient hits and
plosives that often contain more high mid and highs.
SILK
Pushing the button engages the “SILK” circuit. Pushing it a second time introduces the “SILK+”, a
variation on SILK that we tried to make sound more like vintage Class A console circuits.
TEXTURE
“Texture” allows you to adjust the amount of “Silk” from essentially absent, to roughly twice the amount
of coloration found on previous iterations of “Silk”
Much could be written about this feature, but suffice to say that it gives a subtle
option to enhance sound quality in the direction of vintage modules. The SILK
button reduces negative feedback and adjusts the frequency spectrum to
provide a very sweet and musical performance. We suggest you try it and make
your own judgment.
GAIN REDUCTION METER
A 16 segment LED bar-graph meter is fitted for the compressor, calibrated in dB to show how much
gain reduction is taking place. After 4 dB of dynamic attenuation the LEDs become amber and after
8 the LEDs become red. Is that a hint? Not really, because sometimes we need significant amounts of
compression, particularly with some powerful singers. However, the LED colors typically can serve as a
general guide.
OUTPUT METER
The factory calibration sets the top RED LED at the specified output clip point of the Portico II which is
+25 dBu, which is +21 dB over 0 VU. The LEDs are set in one dB increments. That means the bottom red
LED indicates +18 over O VU which is the most typical digital full scale level for pro A to D converters
and the top amber is one dB below clipping for most pro converters. An alternate typical DFS calibration
for semi-pro converters is +14 VU which corresponds to the bottom amber LED (18 dBu). There happens
to be a very good and new trend where we avoid trying to get the signal as close as possible to digital
full scale because it can help our digital tracks sound more analog. In other words, feel free to not light
up any of those amber and red LEDs and don’t feel compelled to make every green one blink.