Rane MC 22 Bedienungsanleitung PDF herunterladen (Seite 4)

Manual-4

OPERATING INSTRUCTIONS

A PRIMER

Let’s start with what a compressor actually does. No

matter how you cut it, this is an automatic volume control. It

is a hand on a knob, turning the volume down and turning it

up again. The hand is really quick and really accurate, but it’s

just turning a volume control.

When the input signal reaches a level set by the THRESH-

OLD control, the compressor begins turning down the signal

by an amount determined by the RATIO control. The MC 22,

like most compressors, operates by making the loud signals

quieter, but does not make the quiet parts louder. However,

by keeping the loud signals under control, the entire system

may be turned up when necessary to make the quiet parts

louder.

PRE-FLIGHT CHECKLIST

Before proceeding, it’s a good idea to turn the control

knobs to the following positions:

1. LEVEL control ....................... 0 dB

2. THRESHOLD control .......... fully clockwise

3. RATIO control ....................... fully counterclockwise

4. COMPRESSOR switches .. ACTIVE (out)

This renders the MC 22 with no compression, but allows

signal through at unity gain. No change occurs either in the

ACTIVE or BYPASS position of the COMPRESSOR switch.

LEVEL

Before making any Threshold adjustments, set the LEVEL

control so the +4 dBu LED lights occasionally, and the OL

LED does not light. Be aware that changes to the Input Level

will affect the Threshold level.

THRESHOLD

The threshold is the point at which gain adjustment

begins. When the input signal is below the threshold, the MC

22 acts like a straight wire. When the signal is loud enough to

cross the Threshold, the compressor is active and turns the

volume down. Various Threshold points are illustrated in

Figure 1 below. How much it gets turned down is determined

by the RATIO control (shown at 2:1).

RATIO

Once the threshold is exceeded, the increase in output

compared to the input signal increase depends on the RATIO

setting. An ordinary preamp set for unity gain or a straight

wire has a ratio of 1:1, that is, the output level tracks the input

level perfectly. A 2 dB change at the input produces a 2 dB

change at the output.

For a 10:1 ratio, a 10 dB blast at the input would rise only

1 dB at the output – heavy compression. Kinder, gentler ratios

are in the 2:1 to 3:1 range. Figure 2 illustrates various Ratios.

Figure 1. Set to 2:1 Ratio. Thresholds at -40 dBu, -20 dBu, and 0 dBu.

Vertical axis = output level, horizontal axis = input level.

FIgure 2. Threshold at -20 dBu. Ratios of 1:1, 2:1, 4:1, and 10:1.

Vertical axis = output level, horizontal axis = input level.

Referring to Figure 2, note that the Ratio indicated is the

average over 40 dB of compression. The ratio is initially

lower. This action provides a “soft” response which is less

audible than hard limiting. For example, the 10:1 ratio

response shows an initial ratio of about 6:1 and ends with a

ratio of ∞:1.

ATTACK TIME

Attack is the time which passes between the moment the

input signal exceeds the threshold, and the moment that the

gain is actually reduced. This can be a difficult control to set,

so Rane made it easier by pre-setting an attack time of 30 ms/

10 dB step, an optimal setting for a wide variety of material.

RELEASE TIME

Release time is the time which passes between the

moment the input signal drops below the threshold and the

moment that the gain is restored. Another difficult control for

the average user to adjust, Rane presets the release rate at

0.3 dB/ms.

LIMITING

A limiter is a special form of compressor set up especially

to reduce peaks for overload protection. In other words, it is

a compressor with a maximum ratio. A compressor is usually

set up to change the dynamics for purposes of aesthetics,

intelligibility, or recording or broadcast limitations. Once the

threshold of a limiter is reached, no more signal increase is

allowed. The MC 22 acts as a limiter when set at a very high

ratio of 10:1.

0 dBu

-20 dBu

-40 dBu

1:1

2:1

4:1

10:1

1 2 3 4 5 6 7 8 9 10 11

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