Cedar DNS1000 User manual

CEDAR
DNS1000
dynamic noise suppressor
OWNER’S MANUAL
© 2000 CEDAR Audio Ltd
Manual version 1.00: August 2000

TABLE OF CONTENTS
INTRODUCTION ..............................................................1
SAFETY INSTRUCTIONS ................................................2
SETUP ..............................................................................3
AUDIO CONNECTIONS AND INDICATORS....................4
FRONT-PANEL INDICATORS AND CONTROLS ..............5
OPERATING THE DNS1000 ............................................7
CASE STUDIES ................................................................9
Case 1: Traffic noise and other ambient sound ..................9
Case 2: Tape hiss ..............................................................11
Case 3: Excessive reverberation ......................................12
SPECIFICATIONS ..........................................................13
EMC REGULATIONS......................................................13
LICENCE AND LIMITED WARRANTY ............................14

PAGE 1
INTRODUCTION
Thank you for purchasing this CEDAR DNS1000 Dynamic Noise Suppressor.
Quality, speed and simplicity are paramount considerations in the DNS1000 design,
and its features include the following:
■Near zero latency
The DNS1000 has a group delay of less than 10 samples (typically less than
1/200th of a frame) so there is no loss of lip-sync caused by its use.
■Flexibility
The DNS1000 will handle a wide range of noise suppression requirements.
■Speed and ease of use
The DNS1000 offers a carefully designed control surface that maximises
operator comfort and speed of use.
■Audio interfaces
The DNS1000 incorporates a 24-bit digital audio interface conforming to
both AES/EBU and SPDIF standards.
■Power requirements
Its universal power supply means that a DNS1000 will work anywhere in
the world.
■Dual processors
A pair of 40-bit floating point DSP processors deliver 120MFlops so that the
DNS1000 will handle the most complex processing requirements.

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SAFETY INSTRUCTIONS
Read these instructions, and follow them.
■Water and moisture
The unit must not be exposed to rain or moisture. Furthermore, if the unit is
brought directly from a cold environment into a warm one, moisture may
condense inside it. This, in itself, will not cause damage, but may cause
electrical shorting. This could damage the unit, and even cause danger to
life. Always allow the DNS1000 to reach ambient temperatures naturally
before connecting the mains power.
■Mounting and ventilation
You should place the DNS1000 on a flat, stable surface. Do not subject it to
strong sunlight, excessive dust, mechanical vibration or periodic shocks.
The DNS1000 is not susceptible to excessive heat build-up, but should be
installed away from heat sources such as radiators and audio devices that
produce large amounts of heat.
■Power sources
The DNS1000 features a universal power supply that will work safely on any
mains supply in the range 85V to 260V, 50Hz or 60Hz AC only. The unit
should always be grounded (‘earthed’), and you should route power cables
so that they will not be walked on or pinched.
■Connections
Turn off the power to all equipment before making any connections.
■Cleaning
Clean the unit only with a dry cloth. Never use abrasive pads or liquid
cleaners such as alcohol or benzene.
■Damage requiring service
The DNS1000 contains no user-serviceable parts and should on no account
be opened or dismantled by unauthorised personnel.
It should be returned to qualified service agents when it has been exposed
to liquids, when it fails to function correctly, when it has been dropped, or
when the case is damaged.

SETUP
Unpacking
Unpack the DNS1000 carefully. Save the carton and all packing materials since
you may need them to transport the unit in the future. In addition to the DNS1000
and the packaging, the carton should contain the following:
■mains connection lead
■this manual
■a warranty registration card.
Installation site
To maintain reliability and prolong operating life, observe the following
environmental considerations:
■the temperature should be maintained between 5 and 30 Celsius
■relative humidity should be in the range 30% to 80% non-condensing
■strong magnetic fields should not exist nearby.
Brightness control
You can adjust the brightness of the front panel indicators (buttons and Activity
LEDs) to suit local lighting conditions:
■with power OFF press and hold Bypass
■continue to hold Bypass and turn the power ON
■adjust the brightness using the Level control
■release Bypass.
This setting is stored in non-volatile memory and will be recalled when you next
use the DNS1000
PAGE 3

AUDIO CONNECTIONS AND INDICATORS
Connections
The DNS1000 offers two audio connection standards. It passes its signal to both
outputs irrespective of the input used. The standards are:
■Digital SPDIF format
■Digital AES/EBU format
The DNS1000 is not affected by channel status data. It will echo any such data
directly to the outputs.
Indicators
The DNS1000 rear panel offers two pairs of LED indicators. The upper pair display
information relating to audio signal sample frequencies. The lower pair show
which input is in use.
■Frequency LEDs
If the “44” LED is lit, the input sample rate is 44.1kHz. If the “48” LED is lit, the
input sample rate is 48kHz. If both LEDs are lit, the input sample rate is 32kHz.
If one or both LEDs are flashing, the DNS1000 is receiving a signal that is close to,
but outside the industry tolerances for that sample rate. The unit will operate
correctly, but with the filterbank frequencies scaled by a corresponding amount.
■Input LEDs
If the AES LED is lit, the DNS1000 is receiving data through its AES/EBU input. If the
SPDIF LED is lit, the unit is receiving data through its SPDIF input. If data is
presented to both inputs simultaneously, the input that was first locked to audio
will retain priority.
If both LEDs are flashing alternately, the DNS1000 is unable to detect a valid signal
and can not lock to either input.
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PAGE 5
FRONT-PANEL INDICATORS AND CONTROLS
■Channel Selector
You can use the DNS1000 to process channel 1, channel 2, or both channels
presented to the active input.
■Range Selector
The Range Selector concentrates the unit’s activity into the desired part of
the audio spectrum.
■Level control
The Level control tells the DNS1000 how much noise is present in the input.
■Band Gain controls
The Band Gain controls determine the maximum amount of processing that
the DNS1000 will apply in each band.
■Activity LEDs
These offer a visual indication of the activity in each of the Bands.
■Bypass
This control allows you to monitor the processed or unprocessed signals.

PAGE 6