Rane DC24 User manual

Manual-1
DC 24
DYNAMIC CONTROLLER
OPERATORS MANUAL
DC 24 CONNECTION
Placing the DC 24 within the chain of events in your
system varies slightly depending on application. If you are
assembling a sound reinforcement system, the DC 24 would
typically be placed between the equalizer (you do use one,
don’t you?) and the active crossover, or the power amplifier if
passive crossovers (or the DC 24 crossover) are used.
In recording applications, the DC 24 may be used in
conjunction with insert loops on the mixing console or in
series with the outputs en route to the recorder. Most consoles
allow headphone monitoring of the processed signal if the
device is connected to the inserts. A most useful feature. If
the DC 24 is used on mixdown, it may be connected to the
output of the multichannel recorder or again on inserts of the
mixdown console.
Many recording situations require that the DC 24 be
connected to the patch bay in the system so it may be easily
moved from one signal location to another. This call should
be made based upon the requirements of the application.
Wiring of this and all components should follow the
Sound System Interconnection RaneNote included in this
manual. This note details standard wiring conventions which
should be used to prevent noise and distortion. Also see the
Chassis Ground note on page Manual-3.
QUICK START
Shredded, this document makes excellent packing material. In its present form, it makes interesting and useful reading.
If you run out of patience quickly, at least read this part to make sure you don’t exterminate everything in a two mile radius
by doing something wrong.
In a nutshell, to use the DC 24 as a conventional dual channel compressor/limiter, ensure that the CROSSOVER
ENGAGE switch on the rear is in its out position. Attach one or two channels of inputs and outputs to the respective
connectors on the rear. With all RATIOS down, LIMITER THRESHOLD all the way up and the LEVEL controls in
center-detent you have an expensive patch cord. Make sure the BYPASS switches are out and set the GATE and COM-
PRESSOR for the desired ratios and thresholds. Turning the LIMITER THRESHOLD down decreases the level at which
limiting occurs. The GATES and COMPRESSORS may both be activated by the source material applied to Channel 1 if
the DUAL/SLAVE switch is pressed in. This is a normal condition for true stereo program material.
To use the DC 24 's crossover bandsplit mode, be sure the rear panel CROSSOVER ENGAGE switch is in. Connect
the input to CH 1/CROSSOVER IN. With the rear panel OUTPUTS switch set to SEPARATE, split outputs are available
at the CH 1/LOW OUT and CH 2/HIGH/COMBINE OUT jacks. With the OUTPUTS switch at COMBINE, use only
the CH 2/HIGH/COMBINE OUT jack for a mono sum of high and low channels.
NEVER CONNECT ANYTHING EXCEPT AN RS 1 OR OTHER APPROVED RANE AC POWER SUPPLY
TO THE THING THAT LOOKS LIKE A TELEPHONE JACK ON THE REAR OF THE DC 24. This is an AC input
and requires some special attention if you do not have an operational power supply EXACTLY like the one that was
originally packed with your unit.
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Manual-2
FRONT PANEL DESCRIPTION
1. POWER switch. It has been a tradition at Rane Corporation to say something clever about the POWER switch on all its
products. Certain government restrictions now eliminate our option of continuing this tradition. Pity.
2. POWER indicator LED. This solid-state illumination device lights up to let the operator know Item 1 (above) is working
and the thing is plugged-in.
3. GATE/EXPANDER THRESHOLD control. This rotary control allows the operator to set the input level below which the
Gate/Expander operates.
4. GATE/EXPANDER THRESHOLD LED. This yellow LED illuminates any time the input signal falls below the threshold
level set by its neighboring knob to the immediate left.
5. GATE/EXPANDER RATIO control. This rotary control determines the ratio to be applied to the Gate/Expander function.
Increased clockwise rotation increases the circuit slope. The full counter-clockwise position disables the Gate/Expander.
6. COMPRESSOR THRESHOLD control. The position of this rotary knob determines above what input level the Compres-
sor functions. Full clockwise rotation disables the Compressor entirely.
7. COMPRESSOR THRESHOLD LED. This yellow LED illuminates any time the input signal exceeds the level at which
the COMPRESSOR THRESHOLD control is set.
8. COMPRESSIOR RATIO control. This rotary control determines the slope of the Compressor once it has exceeded the
indicated threshold. Full counter-clockwise rotation of the RATIO control disables all Compressor activity.
9. LIMITER THRESHOLD control. This rotary control determines above what level the Servo Locked Limiter™ functions.
Full clockwise rotation of this knob disables all Limiter activity.
10. LIMITER THRESHOLD LED. This LED illuminates any time the input exceeds the LIMITER THRESHOLD setting.
11. GAIN REDUCTION meter. This five segment LED meter indicates the amount of reduction, below unity, being applied
to the audio signal by the VCA.
12. BYPASS switch. When pressed in, this Channel in the DC 24 is is hard-wire Bypassed. Each Channel may be individually
Bypassed for comparison and alignment purposes. See OPERATING INSTRUCTIONS on page Manual-4.
13. OUTPUT LEVEL control. This rotary control increases or decreases the output gain of each Channel by 12 dB. In the
center detent, gain will be unity. (NOTE: Channel 2 OUTPUT LEVEL controls overall output in COMBINE mode.)
14. SIGnal present LED. This LED illuminates any time the input signal exceeds approximately -40 dBu.
15. OverLoad LED. This LED illuminates any time the output exceeds a level equal to -4 dB below the clipping level.
16. DUAL / SLAVE mode switch. In the in (SLAVE) position, this switch causes both Channels’ Gate, Compressor and
Limiters to act together, i.e., they are “slaved.” All controls for both Channels remain active, so independent settings are
still possible; however, whenever a signal in one Channel exceeds its settings, then both Channels change by the same
amount. In the out (DUAL) position, both Channels operate independently.
17. CROSSOVER FREQUENCY control. This rotary control selects the crossover frequency. What did you think?
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Manual-3
REAR PANEL DESCRIPTION
1. CHANNEL 1 INPUT. These connectors deliver signal to both Channel 1 of the processor and to the crossover circuit.
2. CHANNEL 1 / LOW PASS OUTPUT. These connectors deliver signal from Channel 1’s processing circuitry and repre-
sents the low pass portion of the signal when the CROSSOVER ENGAGE switch (7) is in the in position.
3. CHANNEL 2 INPUT. This connector delivers signal to Channel 2’s processor only. It is disconnected when the CROSS-
OVER ENGAGE switch (7) is in its in position.
4. CHANNEL 2 / HIGH PASS / COMBINED OUTPUT. This connector makes the signal from Channel 2 available to the
outside world and is the high pass portion of the audio when the CROSSOVER ENGAGE switch (7) is in its in position. If
the SEPARATE / COMBINE switch (8) is in the COMBINE position, this output produces the sum of Channels 1 & 2 and
its overall level is controlled by CH 2 OUTPUT LEVEL.
5. SIDE-CHAIN. Inserting a ¼" TRS plug into this jack breaks the input signal path to both the Compressor and Gate control
circuit. Inserting an equalizer in this loop enables greater compression of boosted equalizer frequencies. The standard
convention is used of TIP=SEND & RING=RETURN.
6. INPUT GAIN TRIM switch. In its +4 dBu position, the input gain of the respective Channel is unity. In the -10 dBV
position, the input gain is increased by 12 dB (although mathematically suspicious, it really is 12 dB, not 14 dB) to com-
pensate for certain recording devices. This switch must be in the +4 dBu position for front panel calibration accuracy.
7. CROSSOVER ENGAGE switch. In its in position, this switch places the low pass portion of the audio signal on the CH 1/
LOW OUT jack, and the high pass portion on CH 2/HIGH/COMBINE OUT.
8. SEPARATE / OUTPUT COMBINE switch. In the COMBINE mode, the outputs of Channel 1 and Channel 2 are added
together and delivered to the CH 2/HIGH/COMBINE OUT connector. This feature is supplied to allow an input to be split
by the crossover, high pass and low pass delivered to separate processor channels, and recombined at the output of the unit.
The COMBINE mode has no effect on the output of Channel 1.
9. Remote POWER supply input. The DC 24 is supplied from the factory with a Model RS 1 Remote Power Supply suitable
for connection to this input jack. The power requirements of the DC 24 call for an 18-24 volt AC center-tapped transformer
only. This is not a telephone jack. Never use a power supply with your DC 24 other than the one supplied or an exact
replacement obtained from Rane Corporation. Using any other type of supply may damage the unit and void the warranty.
10. Chassis ground point. A 6-32 screw is used for chassis grounding purposes. See the CHASSIS GROUNDING note below.
CHASSIS GROUNDING
If after hooking up your system it exhibits excessive hum or buzzing, there is an incompatibility in the grounding
configuration between units somewhere. Your mission is to discover how your particular system wants to be grounded.
Here are some things to try:
1. Try combinations of lifting grounds on units that are supplied with ground lift switches or links.
2. If your equipment is in a rack, verify that all chassis are tied to a good earth ground, either through the line cord
grounding pin or the rack screws to another grounded chassis.
3. Units with outboard power supplies, such as the DC 24, do not ground the chassis through the line cord. Make sure
that these units are grounded either to another chassis which is earth grounded, or directly to the grounding screw on an AC
outlet cover by means of a wire connected to a screw on the chassis with a star washer to guarantee proper contact. If you
are connecting the DC 24 outputs directly to a power amplifier, be sure to connect a ground wire to the amplifier chassis.
Refer to RaneNote 110, “Sound System Interconnection” (supplied in this manual) for further grounding information.
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Manual-4 All features & specifications subject to change without notice. MAR98
OPERATING INSTRUCTIONS
Once all of the inputs and outputs are properly connected
in accordance with the preceding section, normal operation of
the DC 24 should be achievable. If any of the following
procedures do not appear to produce the required results, take
a step backwards and check your wiring.
PRE-FLIGHT CHECKLIST
Before proceeding, it’s a good idea to turn the control
knobs to the following positions:
1. POWER...off
2. EXPAND / GATE THRESHOLD...FULL CCW
3. EXPAND / GATE RATIO...FULL CCW
4. COMPRESSION THRESHOLD...FULL CCW
5. COMPRESSION RATIO...FULL CCW
6. LIMIT THRESHOLD...FULL CW
7. OUTPUT LEVEL...CENTERED IN ITS DETENT
Set all pushbuttons on the front and rear to their out
positions. The OUTPUTS slide switch should be in the
SEPARATE position. The gain TRIM switches should be in
their +4 dBu positions.
LIMITING
With all of the preceding properly accomplished, turn the
POWER switch on (be sure your amp is turned down). The
DC 24 is now nothing but a unity gain amplifier. Cycling the
BYPASS switches with audio passing through the unit should
yield no difference in level or sound dynamics. The GAIN
REDUCTION meters should indicate 0 and nothing else.
Assuming your input signal has peaks in excess of -20 dBu,
you should be able to rotate the LIMITER THRESHOLD
controls CCW and see some gain reduction occur on the
meter simultaneously with a randomly illuminating THRESH-
OLD LED. You should begin to hear the difference. Leave
these controls at whatever Limit level is appropriate for your
application.
COMPRESSION
To use the Compressor, set the COMPRESSOR THRESH-
OLD for an appropriate level, you should see the associated
LED illuminate as signal goes above and below this level.
The COMPRESSOR RATIO control adjusts the gain reduc-
tion slope above the level you have set.
GATE / EXPANDER
The Gate / Expander function works similarly. If the
GATE/EXPANDER THRESHOLD is still fully CCW, rotate
the GATE/EXPANDER RATIO to its full CW position. Stop
your audio source and you will see the GAIN REDUCTION
LEDs drop to the -24 dB position. This indicates that the DC
24 Channel is in the fully gated mode. If you wish to have
gating occur at a higher level, rotate the GATE/EXPANDER
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THRESHOLD control CW to a higher level. If you wish to
create special effects with this gate, you may elect to use a
lower GATE/EXPANDER RATIO setting. This inhibits full
gating by the amount indicated around the control. Experi-
ment with all the controls to obtain the required results.
STERNO
When using the DC 24 as a true stereo (a.k.a. sterno; hey,
lighten up, it’s a joke!) processor, left channel in Channel 1
and right channel through Channel 2, it is a good idea to
operate the unit in the SLAVE mode to prevent large balance
and image shifts. While in the SLAVE mode, both channels
attenuate by exactly the same amount when the Gate and
Compressor work, maintaining the stereo image.
ATTENTION SHOPPERS
This seems like a good place to throw in a few words of
caution. The DC 24 allows a great deal of flexibility. As such,
it also allows one to come dangerously close to completely
destroying an otherwise respectable audio signal if some
thought and care is not put into the operation of the unit.
There are combinations of THRESHOLD and RATIO settings
on the Gate, Expander and Limiter which allow each to fight
the others and in some cases completely cancel. The same
caution applies to any signal processor, such as an equalizer
or crossover, however these are a bit more intuitive and less
likely to be used in a destructive manner. Just be gentle at
first and you should not encounter too much difficulty. If you
become overwhelmed, go back to the PRE-FLIGHT CHECK-
LIST for initial control settings and start over.
BYPASS SWITCHES IN CROSSOVER & COMBINE MODES
Crossover Mode. Do not use the BYPASS switches when
in the CROSSOVER mode. Use of BYPASS in the crossover
mode is potentially destructive since these switches route full
bandwidth audio to drivers designed only for a limited
frequency range. (CH 2 BYPASS is automatically defeated,
but Ch. 1 is still active — do not engage the CH 1 BYPASS
for any reason.)
Combine Mode. As more users (particularly bass guitar
players) discover new applications for this mode, they want to
use BYPASS as an aid in optimizing settings. Unfortunately,
the BYPASS switches do not operate in the COMBINE mode;
however, a simple trick solves the problem:
1. Permanently engage the CH 1 BYPASS switch.
2. Patch CHANNEL 1 OUTPUT to CHANNEL 2 INPUT
using either the ¼" TRS or the XLR jacks. Be sure to use
2-conductor shielded cable.
3. The CH 2 BYPASS switch now operates in the COMBINE
mode.
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