Rupert Neve Shelford 5051 Inductor EQ / Compressor - Manual (Page 12)

12
let the output rise by 1 dB implying 9 dB of compression, 2:1 will cause the output to increase 5 of those
initial 10 dB suggesting 5 dB of reduction. Some engineers relate ratios of 20:1 and higher with limiting,
however technically traditional limiting also requires very fast attack times to respond to transients and
prevent signals from actually going above a certain level.
COMP IN
Engages the compressor, and is indicated by a green button. Other than simply engaging the compressor,
engineers often toggle this button to aid adjusting the make-up gain for similar average levels. The
comp in button is also used to compare the untreated signal to the compressed signal to verify a positive
change is being made.
THRESHOLD
Sets the level where the compressor begins to react and respond to signals above the set threshold. With
the knob set clockwise, only extremely loud signals might cause any gain reduction. With the knob set
counter-clockwise, even relatively quiet sounds can cause compression.
GR METER
Indicates how many dB’s of gain reduction are happening at a given time. This particularly aids in
choosing threshold and ratio settings. While the GR meter is great to confirm what we think we are
hearing, usually our listening skills provide a more direct path to choosing compressor settings than
meters. The meter will generally indicate very brief gain reductions but will tend to exaggerate the
duration so that the eye can see transient compression.
LEVEL METER
Displays the final peak output level of the 5051 regardless of whether the unit is set for EQ PRE or POST.
This meter assists adjusting the compressor gain, and helps prevent equipment that the 5051 may be
feeding from clipping or overloading. In the case of A to D converters, one should primarily depend
on the converters own meters due to possible converter calibration variables. The 5051 level meter is
calibrated for dBu, and the red LEDs may not necessarily match up with the destination device. It is
often advisable to maintain levels 10 to 20 dB below the destination’s maximum input for ease of later
processing.
S/C INSERT SND
A 1/4” unbalanced phone jack used to send the signal to an external device, primarily EQ, to create a
key signal (it can be any old EQ or device since the audio isn’t effected). For example, you may EQ the
signal, cutting all the lows and boosting somewhere between 5 kHz and 8 kHz to cause the compressor
to respond to frequencies associated with sibilance, and become a de-esser. An engineer can also gently
reduce lows and increase mid highs so that the compressor may respond similarly to how our ears may
perceive apparent loudness.
S/C INSERT RET
A 1/4” phone unbalanced input jack that is receives the signal from the external device described above.
The S/C insert return may also be used as a key input. For example, an engineer might wish to patch in
a kick drum to control the compression happening on a bass guitar being run through the 5051.
IMPORTANT NOTE: The S/C insert return is a half-normal connection, meaning that if a plug is inserted
into the jack, it will interrupt the S/C signal path, and whatever signal is present on the plug will now be
the controlling the compressor side-chain, i.e., if there is no signal present on the plug, there will be no