Klark Teknik DN500 Plus User Manual

DN500

OPERATORS MANUAL

Klark Teknik Group,

Klark Teknik Building,

Walter Nash Road,

Kidderminster.

Worcestershire.

DY11 7HJ.

England.

Tel:[phone]

Fax:[phone]

Email: [e-mail]

Website: www.klarkteknik.com

DN500Plus Dual Compressor/Limiter/Expander Operators Manual

(c) Klark Teknik Group (UK) PLC.

In line with the company’s policy of continual improvement, specifications and function may be

subject to change without notice. This Operators Manual was correct at the time of writing. E&OE.

Issue 1.1 - September 2004DOC02-DN500+

IMPORTANT SAFETY INSTRUCTIONS

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,

DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE

AVIS: RISQUE DE CHOC ELECTRIQUE. NE PAS OUVRIR

These symbols are internationally accepted symbols that warn of potential hazards with
electrical products.

The lightning flash with arrowhead symbol, within an equilateral
triangle is intended to alert the user to the presence of uninsulated
“dangerous voltage” within the product's enclosure that may be of
sufficient magnitude to constitute a risk of electric shock to persons.

The exclamation point within an equilateral triangle is intended to alert
the user to the presence of important operating and maintenance
(servicing) instructions in the literature accompanying the appliance.

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any of the ventilation openings. Install in accordance with the manufacturers
instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus
(including amplifiers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two
blades with one wider than the other. A grounding type plug has two blades and a third grounding
prong. The wide blade or the third prong are provided for your safety. If the provided plug does not
fit into your outlet, consult an electrician for replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched particularly at plugs, convenience
receptacles, and the point where they exit from the apparatus.

11. Only use attachments / accessories specified by the manufacturer.

12. Unplug this apparatus during lightning storms or when unused for long periods oftime.

13. Refer all servicing to qualified personnel. Servicing is required when the apparatus has been
damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or
objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does
not operate normally, or has been dropped.

IEC-60065-Edn7-KT

Walter Nash Road, Kidderminster, Worcestershire. DY11 7HJ. England

Tel: [phone]. Fax: [phone]

Company Registration No: 2414018

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SIGNAL PROCESSING BY DEFINITION DESIGNEDFOR APUREPERFORMANCE

DECLARATION OF CONFORMITY

Klark Teknik Group (UK) PLC

We,

of, Klark Teknik Building, Walter Nash Road, Kidderminster, Worcestershire, DY11 7HJ

Declare that a sample of the following product:-

Product Type Number Product Description Nominal Voltage (s) Current Freq

DN500 Plus Dual Compressor / 115V AC 200mA

Limiter / Expander 230V AC

100mA

to which this declaration refers, is in conformity with the following directives and/or standards:-

Directive(s) Test Standard(s)

89/336/EEC Electromagnetic Compatibility Directive
amended by 92/31/EEC & 93/68/EEC 73/23/EEC,
Low Voltage Directive, amended by 93/68/EEC
Generic Standard Using EN55103 Limits and Methods EN50081/1
Class B Conducted Emissions Pavi EN55103
Class B Radiated Emissions Pavi EN55103
Fast Transient Bursts at 2kV EN61000-4-4
Static Discharge at 4kV EN61000-4-2
Electrical Stress Test EN60204
Electrical Safety UL6500-99

EN60065:1998
E60065-00

50/60Hz

Signed:............................

Date: 15th September 2003

Name: Simon Harrison

Authority: Research and Development Director, Klark Teknik Group (UK) PLC

Attention!
Where applicable, the attention of the specifier, purchaser, installer or user is drawn to special limitations of use
which must be observed when these products are taken into service to maintain compliance with the above
directives. Details of these special measures and limitations to use are available on request and are available
in product manuals.

A Subsidiary of Telex communications, Inc.

Contents

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Klark Teknik DN500
After you have unpacked 3

Introduction 5

Instrument Familiarisation

Front panel controls 7
Rear panel controls 8

Audio Connections 11

Using the DN500 13

Compression

Setting the Controls 15

Expansion

Setting the Controls 18

Limiting

Compression, Expansion and Limiting together 20

Application notes

Linking to the Console 21
Using the Side Chain 22
De-essing 23

1

14

17

19

Technical Specification 25

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.

The Klark Teknik DN500

Thank you for selecting the Klark Teknik DN500 Plusdual compressor / limiter / expander.The unit continues
the Klark Teknik tradition ofproviding superb audio performance, technical accuracy and rugged reliability.

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Precautions

Do not install this unit in a locationsubjected to excessive heat, dust or mechanical vibration.

Voltage Selectionand PowerConnection

Connection is made by means of an IEC standard power socket. The rear panel text indicates thevoltage range
required for satisfactory operation of the unit.

Before connecting this unit to the mains supply, ensure the fuse fitted is the correct type and rating is as
indicated on the rear panel, adjacent tothe fuse holder.

Safety Warning

This unit is fitted with a standard fused IEC mains inlet: For safety reasons the earth lead should never be
disconnected.

To prevent shock or fire hazard, do not expose the unit to rain or moisture. To avoid electrical shock do not
remove covers. Refer servicing to qualified personnelonly.

Attention! Cables

This product should only be used with high quality, screened twisted pair audio cables, terminated with metal
bodied 3-pin XLR connectors. Any other cable type or configuration for the audio signals may result in
degraded performance due to electromagnetic interference.

Electric Fields:

Should this product be used in an electromagnetic field that is amplitude modulated by an audio frequency
signal (20Hz to 20kHz), the signal to noise ratio may be degraded. Degradation of up to 60dB at a frequency
corresponding to the modulation signal may be experienced under extreme conditions (3V/m, 90%
modulation).

1

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2

After You Have Unpacked The Unit

Save all the packing materials - they will prove valuable should it become necessary to transport or ship this
product.

Please inspect this unit carefully for any signs of damage incurred during transportation. It has undergone
stringent quality control inspection andevery possibleeffort has been madeto ensurethat it left the factory in
perfect condition.

If, however, the unit shows any signs of damage, please notify the transportation company without delay.
Only you, the consignee, may institute aclaim against the carrier for damage during transportation.

If necessary, contact your supplier or as a last resort, your Klark Teknik importing agent, who will fully co­operate under such circumstances.

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Side Up

This

KIDDERMINSTER ENGLAND

3

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4

Introduction

Compression, expansion, limiting and peak clipping are four of the most valuable techniques available to the
sound engineer. Not only can they solve many problems that can arise in day to day work, creative
possibilities exist in abundance.

The Klark Teknik DN500 Plus Dual Compressor/Limiter/Expander integrates all of these processes into a
single, compact, rack mounting unit with two channel operation. Complete dynamic control over gain is the
result, and also control over problems due to noise in the signal chain and the distortion that may be caused by
excessive peak levels.

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As a compressor, the DN500 can achieve almost undetectable dynamic range reduction by the use of
sophisticated automatic attack and release circuitry. Or compression can be used as an effect in its own right
with full manual control over Threshold, Ratio, Attack and Release. There is also a fully adjustable 'Knee'
control which provides an infinite range ofcompression styles from Hard to Soft, 'easy' compression.

As an expander, the DN500 offers variable ratio expansion which can be used to increase subtly the
dynamic range of a signal, or toact as a conventional noise gate, or offer any degreeof expansion in between.

To control signal peaks, a Limiter is provided on each channel totally independent of the Compressor, and
with a fully adjustable Threshold control. For situations where absolute control over peaks is necessary, a
Peak clipper can be switched in, thethreshold of which tracks the Limiter.

The DN500 has light indicators for every switched audio function, and also has separate gain reduction
light bar graph meters for compression and expansion on each channel. There are also peak limiting light
indicators and output level light bar graphmeters for each channel.

Separate side chain inputs are provided for the Compressor and Expander sections. A stereo link function is
available for operation of the Compression and Expansion functions of both channels of the unit from the
controls of channelA.

The DN500 Dual Compressor/Limiter/Expander is built to Klark Teknik's high standards of design and
construction. A well thought out aesthetic presentation is also an aid to realising full dynamic control over
gain in today's complex productions.

Plus

Plus

Plus

Plus

5

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6

Instrument Familiarisation: Front Panel Controls

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12

15

13

14

7

6

1

2

9

8

3

4

5

10

11

16

17

18

The DN500 Plus Dual Compressor/Limiter/Expander consists of two identical channels, each with separate
Compressor,Expander and Limiter sections.

Compressor

1. determines the level above which gain reduction (compression) will take place, variable

Threshold

from +20dBu down to -30dBu. The Gain Reductionlight bar graphmeter indicatesin decibels byhow
much the signal is compressed at anyinstant.

2. sets the degree of compression applied above the threshold level, variable from 1:1 to 50:1. A

Ratio

ratio of 1:1 corresponds to zero compression : Signal In = Signal Out. A ratio of 10:1 indicates that
when the input signal, above the threshold,rises in level by 10dB, the output level will rise 1dB.

3. calibrated from 1 to 40, adjusts the 'hardness'or 'softness' of the compression effect. Ahard knee

Knee

means that when the input signal level rises above the threshold, it is immediately compressed at the
full ratio as set. Asoft knee means that compression will start below the threshold level at a low ratio
and gradually attain the full ratio selectedonly at higher levels.

4. sets the time taken for compression to commence after the threshold is exceeded, from 0.05

Attack

milliseconds (50 microseconds) to 20 milliseconds.

5. determines the time taken for the gain to return to normal after the signal drops below the

Release

threshold level, adjustable from 60 milliseconds to2 seconds.

6. The switch selects the whole channel to be in or out of circuit.

7. links the two channels of the DN500 Plus together, so that they are both operated from the

Bypass

Stereo

controls of Channel A, apart from the Limiter sections which always work individually. In stereo
mode, the unit still monitors the levelsof both channels to detect when the signal is above the threshold
level (on Channel B, the Stereo switch is replaced by a 'Stereo Slave' light indicator).

8. selects the compression effect to be in or out.

9. allows the setting of attack and release times to be automatic or manual. On Auto, the attack

Comp In

ENV

time of the input signal and the amount by which it exceeds the threshold level are assessed, and
suitable Compressor attack and release values set to give an almost undetectable
reduction in signal dynamic range. On Manual, the rotary Attack and Release controls come into
operation.

7

Expander

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10. determines the level below which gain reduction will take place, variable from 20dBu

Threshold

down to -40dBu. Gain reduction BELOW a threshold level constitutes dynamic range EXPANSION.
The Gain Reduction light bar graph meter indicates in decibels by how much the signal is expanded at
any instant.

11. sets the degree of expansion applied below the threshold level, variable from 1:1 to 25:1. A

Ratio

ratio of 1:1 corresponds to zero expansion : Signal In =Signal Out. A ratio of 10:1 indicates that when
the input signal, below the threshold, fallsin level by 1dB, the output level will fall 10dB.

12. determines the time taken for the gain to return to normal after the signal comes back above

Release

the threshold level, adjustable from 40 millisecondsto 2 seconds.

13. (Attack) is a switched control offering either automatic signal-monitored setting of Expander

ATK

attack time or a fixed value of2 milliseconds.

14. is the output level control for the entire channel, Compressor,Expander and Limiter. The output

Gain

level light bar graph meter indicates OUTPUT level when the channel is switched in circuit. When
the channel is bypassed, the meter indicatesINPUT level.

15. selects the expansion effect to be in or out.

EXPIn

Limiter

16, sets the level above which the signal will be limited (compressed at a high 25:1 ratio),

Threshold

adjustable from 0dBu to 20dBu.

17. selects peak clipping. Clipping totally eliminates transient peaks, effectively acting as a

Clipper In

limiter with an infinity:1 ratio and an instantaneous attack time. The Clipper threshold follows the
Limiter threshold as set.

18. switches mains power on or off.

Power

8

Instrument Familiarisation: Rear Panel Controls

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19

115/220-240V

CUS

20

19. is supplied via an IEC standard 3-pin connector. A compatible power cord is supplied with the

Mains

21

26

24

25

22

1

2

3

NEUTRIK

23

1

1

1

2

3

NEUTRIK

2

3

NEUTRIK

2

3

NEUTRIK

unit.

20. The islocated in a fuse holder fittedto the rear panel. Always replace with the correct type

mains fuse

and rating as indicated on the unit.

21. This unit is switchable between two nominal supply voltages, 110V and

Voltage selector switch.

220V, via a slide switch. The switch MUST be set before the supply is connected. Any attempt to run
the unit from a 220V supply with the switch set to 110Vis liable to result in severe damage to the unit.

Note: Units for the Japanese market do not have an accessible mains voltage selector switch and are set for 100V
operation only.

22. Signal is made via a female XLR typeconnector.

23. Signal is available on a male XLR type connector. For wiring details see page 11 of this

Input

Output

manual.

24. is made via a ¼ inch typeA stereo jack connector.

25. is made via a ¼ inch typeA stereo jack connector.

26. Always quote the in any correspondence concerning the unit.

Expander Side ChainInput

Compressor Side Chain Input

Serial Number

9

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10

Audio Connections

Input

The input circuit is a transformerless, electronically balanced design which achieves a symmetry of better
than- 50dB from 20Hz to 10kHz.

If transformer balancing of the input is required, this must be specified at the time of order. It is not
retrofittable.

Output

The standard output is unbalanced, but balancing transformers are available and may be retrospectively
fitted. Please contact your Klark Teknik representative for more information. The output circuitry is capable
of driving a 600 ohm load ata level of +22dBu.

Input

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Output

Unbalanced

2

Unbalanced

1

Balanced

1

3

3

1 Gnd

2 Gnd

3 Hot

Balanced

1 Gnd

2

2 Gnd

3 Hot

2

1

3

1

2

3

1 Gnd

2 Cold

3 Hot

1 Gnd

2 Cold

3 Hot

Pin 2 / Pin 3 Hot Operation

The unit is configured for pin 3 hot operation but can be re-configured to the standard pin 2 hot XLR wiring
convention. This is done by changing the internal jumpers located next to the connectors on the PCB from a
horizontal to a vertical configuration, as illustrated below. Please contact your Klark Teknik service
representative for further details, if required.

Pin 3 hot Pin 2 hot

11

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Side Chain/EXT Key Inputs

The electronically balanced Side Chain inputs areon stereo ¼ inch typeA jack sockets, configured:

TIP = HOT, RING = COLD, SLEEVE = EARTH.

Inserting a mono jack plug will automaticallyunbalance the input.

1/4” Stereo Jack

HOT

COLD

GND

Out

Thru

In

The sockets are internally normalled so that signal continuity is maintained when there is no jack plug
inserted. If the unit is wired to apatchbay,then normalling must be carried out at the patchbay.

Balanced Circuits

Transformer or electronically balanced connections have the benefit of Common Mode Rejection which
eliminates externally induced interference, such as mains hum etc. Balancing is especially useful when long
cable runs are used between pieces ofequipment.

Transformer balanced circuits have the added advantage of being fully floating, with the earth (ground) or
screen being totally isolated from the signal. In installations where a difference in earth potential is likely to
occur,this isolation prevents earthing problems which can, in some cases, damage the equipment.

12

Using the DN500

The natural sounds of life havean extremely widedynamic range, fromthe resultof a fallingleaf to theroar of
a jet engine on take off. The human ear has an automatic gain control which enables it to accommodate all of
these sounds from the thresholdof hearingto close to the threshold of pain, a dynamicrange ofapproximately
120 decibels.

Even the most modern audio equipment is incapable of handling the full range that the ear can cope with.
Analogue tape without noise reduction can manage almost 70 decibels dynamic range between its noise floor
and the 3% distortion point. 16 bit digital audio equipment can achieve over 90dB. Still almost 30dB less
than the ear's range.

Even if a 120dB dynamic range were possible in audio equipment, would it be desirable and useful? A
listener in a domestic setting enjoying the exhilarating effects of a 96dB Sound Pressure Level will almost
certainly be causing his neighbour a significant amount of annoyance, if not distress! At the other end of the
dynamic scale, a typical ambient noise level of at least 40dB SPL precludes the use of very quiet levels in
recorded or broadcast sound media.

Almost always, it is necessary to compress the dynamic range of natural sounds to fit them into a window
suitable both for the equipment and forcomfortable listening.

Although the dynamic range of the programme material must fit into a 30 to 40dB window, there is another
factor in the equation noise. All the sounds that we want to listen to, whether natural or electronically
processed, are accompanied by a certain amount of unwanted background noise tape hiss, or the rustle of
musicians turning the pages of the scorein the studio.

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Even if, in the final programme, the noise level is below the ambient noise of the listening area, it may still be
heard and is therefore undesirable.

The Compressor/Limiter and the Expander are valuable tools for the control of dynamic range and reduction
of noise. Compression reduces the dynamic range of any instrument or programme source. Expansion has
the effect of subjectivelyreducing or eliminating background noise.

Compression and expansion have their artistic uses too. The sounds of instruments and voices can be altered.
A mix of instruments can be compressed to give a 'tighter' dynamic effect. Or a previously over-compressed
recording can have life put back intoit by the subtle use of expansion.

The DN500 Plus Dual Compressor/Limiter/Expander offers in a compact unit virtually complete control over
dynamic range, for corrective and for artisticpurposes.

13

Compression

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One of the principal uses of compression is the control of level in vocals. Many singers train for years to
achieve the degree of breath control necessary for an even tone and expressive performance. Other vocalists
rely on an instinctive voice production technique, which may need help in the studio to maintain a consistent
level, and result in a vocal trackwhich 'sits' correctly in the mix.

The level of a vocal may varywidely,and appear like the unprocessed signal in the diagram :

Threshold level

Signal Level

Threshold level

Unprocessed signal

Time

Signal Level

Signal Level

Threshold level

3:1 Compression above threshold

With gain make up

Diagram 1

Time

Time

The unprocessed signal has a large dynamic range between the highest and lowest levels. Applying
compression reduces the highest levels, reducing the dynamic range. Because the peak level of the signal is
now lower, make-up gain is added to restore the original peak level. The result is a much more controlled and
usable sound.

14

Compression: Setting The Controls

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Threshold

sets the level above which compression takes place. Signals below the threshold will remain
unaltered. Turning the control clockwise lowers the threshold level and allows more of the signal to be
compressed.

Ratio

is the 'strength' of compression above thethreshold level. The higher the ratio, the greater theeffect.

+20

+10

-10

Output level (dB)

Input level (dB)

+10

+20

-20

-10

+20

+10

-10

Output level (dB)

Input level (dB)

+10

+20

-20

-10

-20

2:1

-20

12:1

Diagram 2

At a compression ratio of 2:1, the effect is mild and suitable for the subtle compression of vocals or of a
complete mix. At 12:1,compression is becoming stronger andmore noticeable. Ratios between3:1 and 15:1
are suitable for the 'compressor' sound, used asan effect in its own right. Higher ratios are used forthe control
of extremely peaky signals.

The point where the slope of the Compressor curve changes is knows as the .

Knee

The DN500 Plus has an

adjustable knee, variable between 'Hard' and 'Soft':

Soft Knee

10:1

1:1

Hard Knee

10:1

1:1

Increasing signal level

Increasing signal level

Diagram3

15

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With a soft knee, signals which only just exceed the threshold level are compressed at a low ratio, the ratio
increasing the higher the signal level.

Attack

sets the time the Compressor takes to respond once the threshold has been exceeded. Attack may be
set so that the initial transient of the instrument passes through unaltered, or set to a faster value so that the
very start of the sound is compressed. Particularly with drum sounds, careful adjustment of attack time can
make the sound more 'punchy' and 'driving'.

Release

time plays a very important role in compression. During periods of high signal level, gain is reduced.
When the signal level falls below the threshold, the gain will increase at a rate determined by the Release
control. If the release time is short, the gain will rise quickly. Along release time will mean that the gain will
stay at its reduced level, only recoveringgradually :

Signal Envelope

Input signal

Fast release

Slow release

Diagram 4

The setting of the correct release time is a compromise. If the release time is too short, background noise can
cause effects often known as 'breathing' and 'pumping'. If the release time is too long, the signal will not be
compressed, but simply reduced in level. For effective compression, the release time must be set to as short a
value as possible before modulation of the background noise becomes too noticeable. The gain reduction bar
graph meter will show how much actual compression is going on. If it stays steady, there is little active
compression, just a steady-state reduction in level. The faster the bar graph moves up and down, the harder
the Compressor is working.

For a natural unnoticeable compression, attack and release times may be set to Auto. The signal
characteristics are continuously monitored for optimum values.

16

Expansion

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Expansion may be used to increase the dynamicrange of asignal : ofa performance lacking lifeand vigour, or
of a previously over compressed recording.

Alternatively, expansion can be used to reduce noise, either subtly and undetectably, or with the harder action
of a noise gate.

Threshold level

Signal Level

Unprocessed signal

Threshold level

Time

Signal Level

2:1 Expansion below threshold

Diagram 5

Time

The unprocessed signal has a fairly narrow dynamic range between the highest and lowest levels. Expansion
makes the lower levels lower still, increasingthe dynamic range.

Used as an expander, the DN500 Plus may be connected in the signal chain in exactly the same manner as
when used as a compressor.

17

Expansion:Setting the controls

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Threshold

unaltered. Turning the control anticlockwise raises the threshold level and allows more of the signal to be
expanded. A low thresholdwould be used to reduce noise, a higher threshold to increase the dynamic range of
a signal.

Ratio

At an expansion ratio of 2:1, the effect is mild and suitable for subtle noise reduction or dynamic range
enhancement. At higher ratios the effect becomes harder and more like a noise gate. The light bar graph
indicates the amount of gain reduction takingplace.

Attack

be done automatically, the circuitry continuously analysing the signal to determine optimum attack time. Or
it can be set to a fixedvalue of 2ms.

Release

threshold level. For hard gating, this may be set to a short value. Longer release times are suitable for
dynamic range enhancement or subtle noise reduction.

Gain

light bar graph meter indicates output level when the channel is switched in circuit. When the channel is
bypassed, the meter indicates INPUT level.

sets the level below which expansion takes place. Signals above the threshold will remain

is the 'strength' of expansion below thethreshold level. The higher the ratio, the greater theeffect.

sets the time the Expander takes to respond once the signal has passed below the threshold. This can

determines the time taken for the gain to return to normal after the signal comes back above the

is the output level control for the entire channel, Compressor, Expander and Limiter. The output level

18

Limiting

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The Limiter acts as a last check on signal level. If the level goes over the threshold, fast acting, high ratio
compression is applied to bring it backwithin bounds.

If absolute control over peak levels is required, a Peak Clipper may be switched in, acting in effect as a
compressor with a ratio of infinity:1 andan instantaneous attack time :

Threshold level

Signal Level

Unprocessed signal

Threshold level

Time

Signal Level

Threshold level

Signal Level

Threshold

Limiting

Clipping

Diagram 6

sets the level above which limiting, orslipping if selected, takes place.

Time

Time

19

Compression, Expansion and Limiting

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The act of compressing a signal inevitably causes an increase in noise level. Compression reduces peak
levels; gain make up restores the overall level, and in the process increases the level of any background noise
that the signal contains.

Almost always, when compression is used, the Expandersection of theDN500 Plus will beused also, toclean
up the signal. The Limiter/Clipperwill control any unwanted peaks.

The result is three-stage dynamic control overgain with three different threshold levels:

+20

Limiter Threshold

Compressor Threshold

-20

Expander Threshold

-10

+10

-10

-20

Output level (dB)

Input level (dB)

+10

+20

Diagram 7

In the mid-range of levels, the signal is unaltered. Above the compression threshold, in this example, gain is
reduced by a ratio of 2:1. Above the limiting threshold it is reduced by 25:1. At levels below the Expander
threshold, gain is reduced by 2:1. Complete controlover signal dynamics is possible.

20

Applications: Interfacing with a console

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The Klark Teknik DN500 Plus Dual Compressor/Limiter/Expander is optimised for use at line level,
therefore to process the signal from a microphone, the input to the DN500 Plus has to be taken from the
console preferably from the channel insert point send. The output from the DN500 Plus comes back to
the channel insert return. By connecting the DN500 Plus at this position in the signal chain, its operation
is unaffected by the use of any of the console controls, except Input Gain.

Channel Insert Point

Send

Mic Input

Return

Diagram 8

Output

Input

An alternative is connection to the groupinsert point of the console.

This connection has two uses : the input from the microphone may be compressed post EQ, which offers an
alternative sound quality which may be desirable in some cases. Alternatively, several instruments may be
compressed together in the mix to achievea 'harder' sound.

Group Insert Point

Send

Mic Input

Return

Diagram9

Output

Input

21

Applications: Side chain inputs

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Each channel of the DN500 Plus has two inputs, one for the Compressor and one for the
Expander.

In normal use, the amount of compression or expansion is related to the dynamics of the input signal. The
Side Chain allows the signal passing through the unit to be controlled by the dynamics of another separate
signal.

Connection to the Side Chain input ismade via the rear panel jack sockets. See 'Audio Connections', page 12.

Side Chain

22

Applications: De-essing

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De-essing is an important compression technique using the Side Chain. Many singers have high level
sibilants 'sss' sounds which detract from their performance. Equalising the signal will reduce the sibilants,
but also make the overall vocal sounddull.

The sibilants can be selectively removed by compressing only when there is an excessive level of high
frequencies. Here is one way to do it:

Mic Input

(Channel routed

to group)

Insert Send

(channel 1)

Line In

(channel 2)

Aux Send

Send

Return

Diagram 10

Output

Input

Compressor side

chain input

The microphone channel is routed to a group with the Compressor patched into the group insert points. The
microphone channel is also parallelled into another channel via the line input. The signal in the second
channel is equalised so that high frequencies in the sibilant range are boosted. This channel is fed via an
auxiliary output to the Compressor Side Chaininput.

Now, the Compressor will react whenever there is a sibilant, reducing the gain for the duration of the sibilant
and cleaning up the vocal sound.

This technique can also be used to compensate for a 'boomy' bass, or other situations where a band of
frequencies is occasionally obtrusive.

The DN500 Plus Dual Compressor/Limiter/Expander offers a unique combination of dynamic gain control
processors. Engineers will find it a powerful tool in recording, broadcast and post-production studios, and in
sound reinforcement systems.

23

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24

DN500 Technical Specifications

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CUS

1

1.5s

20

115/220-240V

-5

1

Audio Inputs Two

Type Electronically Balanced
Impedance (ohms)

Balanced 20k
Unbalanced 10k

Side Chain Inputs Two Compressor +

Two Expander

Type Electronically Balanced
Impedance (ohms)

Balanced 20k
Unbalanced 10k

Audio Outputs Two

Type Unbalanced
Minimum Load Impedance 600 ohms
Source Impedance <60 ohms
Maximum Level +21dBu

1

PUSH

1

2

3

NEUTRIK

1

NEUTRIK

1.5s

20

2

3

-5

1

PUSH

1

1

2

3

NEUTRIK

2

3

NEUTRIK

Performance

Frequency Response +/- 0.5dB
(20Hz 20kHz)
Distortion (THD+N) <0.03% @ 1kHz
(@ +4dBu)
Equivalent Input Noise -94dBu
(20Hz 20kHz unweighted)

Compressor

Threshold -30dB to +20dB
Ratio 1:1 to 50:1
Knee 1dB (hard) to 40dB (soft)
Envelope switchable auto (attack and release controls disabled)
Attack (90% capture) 0.05ms to 20ms
Release (90% recovery) 60ms to 2s

Expander

Threshold -40dB to +20dB
Ratio 1:1 to 25:1
Attack switchable auto or fixed (2mS)
Release (90% recovery) 40ms to 2s
Output Gain -10dB to +30dB

Limiter/Clipper

Threshold 0dB to +20dB

Power Requirements

Voltage 100 / 115 / 230 - 240V, 50/60Hz
Consumption <30VA

Termination

Audio Inputs / Outputs 3-pin XLR
Side Chain Inputs normalled ¼ inch stereo jack
Power 3-pin IEC

25

Dimensions

Width 482mm (19 inch)
Depth 292mm (11 ½ inch)
Height 44.5mm (1 ¾ inch)

Weight

Nett 4 kg
Shipping 6kg

Options

Security Cover
Transformer Input / Output balancing*

* Input transformer balancing is non-retrofittable and has to be specified with order.

Options

Security cover
Transformer input*/output balancing
*Input transformer balancing is non-retrofittable and has to be specified with order.

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Options Ordering Information

Perspex security cover SCP.........................Model No.

Aluminium security cover SCA ........................Model No.

Output balancing transformer BU37
Input balancing transformer BN37

Parts Number

26