Cedar DNS1500 User manual

Page 1
OWNER’S MANUAL
© 2007 CEDAR Audio Ltd
Manual version 1.00: September 2007
DNS1500
dialogue noise suppressor
interstage
Phistersvej 31, 2900 Hellerup, Danmark
Telefon [phone], fax [phone]
www.interstage.dk
-pro audio with a smile

Page 2 Page 3
Table of Contents
Introduction .................................................................................................. 5
Safety Instructions ....................................................................................... 6
Setting up the DNS1500 .............................................................................. 7
Unpacking .............................................................................................. 7
Installation Site ....................................................................................... 7
Brightness Control .................................................................................. 7
Creating A Default Setup ........................................................................ 7
Audio Connection ........................................................................................ 8
Connections ........................................................................................... 8
Locking and lock Indicator ..................................................................... 8
Front Panel Indicators and Controls ............................................................ 9
Operating the DNS1500 ............................................................................ 10
Case Studies .............................................................................................. 12
Suppressing traffic noise ...................................................................... 12
Suppressing tape hiss .......................................................................... 14
Suppressing excessive reverberation .................................................. 15
Specifications ............................................................................................ 17
EMC REGULATIONS .................................................................................. 17
License and Limited Warranty ................................................................... 18
Intentionally left blank

Page 2 Page 3
Table of Contents
Introduction .................................................................................................. 5
Safety Instructions ....................................................................................... 6
Setting up the DNS1500 .............................................................................. 7
Unpacking .............................................................................................. 7
Installation Site ....................................................................................... 7
Brightness Control .................................................................................. 7
Creating A Default Setup ........................................................................ 7
Audio Connection ........................................................................................ 8
Connections ........................................................................................... 8
Locking and lock Indicator ..................................................................... 8
Front Panel Indicators and Controls ............................................................ 9
Operating the DNS1500 ............................................................................ 10
Case Studies .............................................................................................. 12
Suppressing traffic noise ...................................................................... 12
Suppressing tape hiss .......................................................................... 14
Suppressing excessive reverberation .................................................. 15
Specifications ............................................................................................ 17
EMC REGULATIONS .................................................................................. 17
License and Limited Warranty ................................................................... 18
Intentionally left blank

Page 4 Page 5
INTRODUCTION
In 2000, CEDAR Audio launched the DNS1000 dynamic noise suppressor. This
was a stand-alone, desktop-format unit designed specifically for film production,
dubbing, outside broadcast (remote) and studio noise suppression. It was ideal
for replacing analogue units that had been in use for many years, and for use in
situations where rapid setup and processing was required ‘on the fly’.
The DNS1500 is a further development of the concepts embodied in its
predecessor, offering improved 2-channel performance and increased sample
rates of up to 100kHz. It is also fully RoHS compliant.
Quality, speed and simplicity are paramount considerations in the DNS1500
design, and its features include the following:
Near zero latency
The DNS1500 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 when using it.
Flexibility
The DNS1500 will handle a wide range of noise suppression
requirements.
Speed and ease of use
The DNS1500 offers a carefully designed user-interface that maximises
speed of use.
Audio interfaces
The DNS1500 incorporates a 24-bit digital audio interface conforming to
both AES/EBU and SPDIF standards.
Universal power supply
Its universal power supply means that a DNS1500 will work anywhere in
the world.
Powerful processor
A 40-bit floating point DSP processor capable of delivering up to
1.2GFLOPS ensures that the DNS1500 can handle the most complex
processing requirements.
Intentionally left blank

Page 4 Page 5
INTRODUCTION
In 2000, CEDAR Audio launched the DNS1000 dynamic noise suppressor. This
was a stand-alone, desktop-format unit designed specifically for film production,
dubbing, outside broadcast (remote) and studio noise suppression. It was ideal
for replacing analogue units that had been in use for many years, and for use in
situations where rapid setup and processing was required ‘on the fly’.
The DNS1500 is a further development of the concepts embodied in its
predecessor, offering improved 2-channel performance and increased sample
rates of up to 100kHz. It is also fully RoHS compliant.
Quality, speed and simplicity are paramount considerations in the DNS1500
design, and its features include the following:
Near zero latency
The DNS1500 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 when using it.
Flexibility
The DNS1500 will handle a wide range of noise suppression
requirements.
Speed and ease of use
The DNS1500 offers a carefully designed user-interface that maximises
speed of use.
Audio interfaces
The DNS1500 incorporates a 24-bit digital audio interface conforming to
both AES/EBU and SPDIF standards.
Universal power supply
Its universal power supply means that a DNS1500 will work anywhere in
the world.
Powerful processor
A 40-bit floating point DSP processor capable of delivering up to
1.2GFLOPS ensures that the DNS1500 can handle the most complex
processing requirements.
Intentionally left blank

Page 6 Page 7
SAFETY INSTRUCTIONS
Read these instructions, and follow them.
Water and moisture
The DNS1500 must not be exposed to rain or moisture. Furthermore, if it
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 DNS1500 to reach ambient
temperatures naturally before connecting the mains power.
Mounting and ventilation
You should place the DNS1500 on a flat, stable surface. Do not subject
it to strong sunlight, excessive dust, mechanical vibration or periodic
shocks. The unit 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 DNS1500 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 DNS1500 only with a dry cloth. Never use abrasive pads or
liquid cleaners such as alcohol or benzene.
Damage requiring service
The DNS1500 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.
SETTING UP THE DNS1500
UNPACKING
Unpack the DNS1500 carefully. Save the carton and all packing materials since
you may need them to transport the unit in the future. In addition to this manual,
the DNS1500 and its packaging, the box should contain the following:
mains connection lead
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 to suit local lighting
conditions:
press and hold the “Chan1” button until all the activity LEDs light
continue to hold this and adjust the brightness using the “Level” fader
CREATING A DEFAULT SETUP
You may replace the factory default setup, which comprises the settings for:
which channels are active for prccessing, the range(s), the Bypass status and
the LED brightness.
To do so, shut down the DNS1500 by holding the Bypass button for two seconds
or more.

Page 6 Page 7
SAFETY INSTRUCTIONS
Read these instructions, and follow them.
Water and moisture
The DNS1500 must not be exposed to rain or moisture. Furthermore, if it
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 DNS1500 to reach ambient
temperatures naturally before connecting the mains power.
Mounting and ventilation
You should place the DNS1500 on a flat, stable surface. Do not subject
it to strong sunlight, excessive dust, mechanical vibration or periodic
shocks. The unit 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 DNS1500 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 DNS1500 only with a dry cloth. Never use abrasive pads or
liquid cleaners such as alcohol or benzene.
Damage requiring service
The DNS1500 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.
SETTING UP THE DNS1500
UNPACKING
Unpack the DNS1500 carefully. Save the carton and all packing materials since
you may need them to transport the unit in the future. In addition to this manual,
the DNS1500 and its packaging, the box should contain the following:
mains connection lead
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 to suit local lighting
conditions:
press and hold the “Chan1” button until all the activity LEDs light
continue to hold this and adjust the brightness using the “Level” fader
CREATING A DEFAULT SETUP
You may replace the factory default setup, which comprises the settings for:
which channels are active for prccessing, the range(s), the Bypass status and
the LED brightness.
To do so, shut down the DNS1500 by holding the Bypass button for two seconds
or more.

Page 8 Page 9
AUDIO CONNECTION
CONNECTIONS
The DNS1500 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 DNS1500 is not affected by channel status data. It will echo any such data
directly to the outputs.
LOCKING AND LOCK INDICATOR
The DNS1500 will by default lock to any AES/EBU signal presented to the rear
panel AES/EBU input. If you wish to use the SPDIF input, you must disconnect
the AES/EBU input cable, or make sure that no AES/EBU signal is present.(It is
not necessary for audio to be passing for the AES/EBU connection to be
recognised.)
The unit will lock automatically to any sample rate presented up to 100kHz. If the
input signal lies outside the industry tolerances for any of the standard sample
rates, the filter table for the nearest standard will be used and scaled
accordingly.
If no lock is possible or there is some other form of I/O error, the Bypass button
will flash slowly.
FRONT PANEL INDICATORS AND
CONTROLS
Channel Selectors
You can use the DNS1500 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 DNS1500 how much noise is present in the input.
Band Gain controls
The Band Gain controls determine the maximum amount of processing that the
DNS1500 will apply in each band.
Activity LEDs
These offer a visual indication of the activity in each of the Bands.
Bypass
Allows you to monitor the processed or unprocessed signals.

Page 8 Page 9
AUDIO CONNECTION
CONNECTIONS
The DNS1500 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 DNS1500 is not affected by channel status data. It will echo any such data
directly to the outputs.
LOCKING AND LOCK INDICATOR
The DNS1500 will by default lock to any AES/EBU signal presented to the rear
panel AES/EBU input. If you wish to use the SPDIF input, you must disconnect
the AES/EBU input cable, or make sure that no AES/EBU signal is present.(It is
not necessary for audio to be passing for the AES/EBU connection to be
recognised.)
The unit will lock automatically to any sample rate presented up to 100kHz. If the
input signal lies outside the industry tolerances for any of the standard sample
rates, the filter table for the nearest standard will be used and scaled
accordingly.
If no lock is possible or there is some other form of I/O error, the Bypass button
will flash slowly.
FRONT PANEL INDICATORS AND
CONTROLS
Channel Selectors
You can use the DNS1500 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 DNS1500 how much noise is present in the input.
Band Gain controls
The Band Gain controls determine the maximum amount of processing that the
DNS1500 will apply in each band.
Activity LEDs
These offer a visual indication of the activity in each of the Bands.
Bypass
Allows you to monitor the processed or unprocessed signals.

Page 10 Page 11
Level control
Your next job will be to identify the noise level of the audio.
With the appropriate channel(s) and range(s) selected, pull all six Band Gain
controls and the Level control down fully. Now increase the Level slowly. At first,
you will hear very little happen but, at some point determined by the noise
content of the recording, you will hear the noise disappear. You should attempt to
find the point at which this occurs.
When you place the Band Gain controls in this position, maximum processing will
occur as you increase the Level control, thus making identification of the noise
easier.
Band Gain controls
Once you have chosen the range(s) and determined the Level, you control the
action of the DNS1500’s filter bank using the Band Gain controls.
The six faders represent six frequency bands distributed from lower frequencies
(left) to higher frequencies (right) across the selected range.
You will use the Band Gain controls to control the amount of noise attenuation
performed in each band, adjusting them to suppress as much noise as possible
without introducing unwanted artefacts into the desired signal.
Noise suppression occurs in a given band when the fader is below the 0dB line.
However, there are occasions when you might wish to boost the signal in a given
band, and you can do this by moving the appropriate fader above the 0dB line.
Activity LEDs
The twelve Activity LEDs offer a visual indication of the activity in each of the six
bands controlled by the Band Gain controls.
Both LEDs off: Less than ±0.5dB activity
Green LED lit: The signal is being attenuated
Red LED lit: The signal is being boosted
The brightness of an LED offers an indication of the amount of attenuation or
boost being applied.
Note that each band controls numerous filters. Therefore, the Activity LEDs in a
given band display the overall activity in that band, and are not necessarily
indicative of the action of any single filter at that moment.
OPERATING THE DNS1500
Introduction
The DNS1500 divides a signal into a large number of well defined bands.
Sophisticated digital filters analyse each of these bands and suppress the noise
independently in each. The innovative design of this filter bank allows you to
control the DNS1500 using relatively few front panel controls.
Bypass
You can route the input directly to the output by pressing the Bypass button. This
allows you to audition the signal before and after processing. The signal latency
is not affected by the Bypass state.
Channel Selector
Your first job will be to identify the channel(s) that include(s) the unwanted noise.
Press the CHAN 1 button if you wish to process channel 1 only. Press the CHAN
2 button if you wish to process channel 2 only. Press both if you wish to process
both channels.
When processing both channels, the DNS1500 uses the same parameter values
for each (as determined by the current settings of the front panel controls) but
responds to the audio in each channel independent of the audio in the other.
Range Selector
Next, you should identify the frequency range or ranges in which the noise lies.
You can press each of the Range Selector buttons individually, or combine them
to choose any one of six possible processing ranges:
Low 20Hz - 400Hz
Mid 200Hz - 6kHz
High 4kHz - maximum
Low + Mid 20Hz - 6kHz
Mid + High 200Hz - maximum
Full Range 20Hz - maximum
The maximum sample rate varies from 12kHz at 32kHz sample rate to
approximately 45kHz at 96kHz sample rate.
To select Low + Mid or Mid + High, press the appropriate two buttons
simultaneously, or in quick succession while the first is flashing. To select Full
Range, press the Low and High buttons simultaneously or in quick succession.
Selecting a range concentrates all of the filters within the DNS1500’s filter bank
across that part of the audio spectrum.

Page 10 Page 11
Level control
Your next job will be to identify the noise level of the audio.
With the appropriate channel(s) and range(s) selected, pull all six Band Gain
controls and the Level control down fully. Now increase the Level slowly. At first,
you will hear very little happen but, at some point determined by the noise
content of the recording, you will hear the noise disappear. You should attempt to
find the point at which this occurs.
When you place the Band Gain controls in this position, maximum processing will
occur as you increase the Level control, thus making identification of the noise
easier.
Band Gain controls
Once you have chosen the range(s) and determined the Level, you control the
action of the DNS1500’s filter bank using the Band Gain controls.
The six faders represent six frequency bands distributed from lower frequencies
(left) to higher frequencies (right) across the selected range.
You will use the Band Gain controls to control the amount of noise attenuation
performed in each band, adjusting them to suppress as much noise as possible
without introducing unwanted artefacts into the desired signal.
Noise suppression occurs in a given band when the fader is below the 0dB line.
However, there are occasions when you might wish to boost the signal in a given
band, and you can do this by moving the appropriate fader above the 0dB line.
Activity LEDs
The twelve Activity LEDs offer a visual indication of the activity in each of the six
bands controlled by the Band Gain controls.
Both LEDs off: Less than ±0.5dB activity
Green LED lit: The signal is being attenuated
Red LED lit: The signal is being boosted
The brightness of an LED offers an indication of the amount of attenuation or
boost being applied.
Note that each band controls numerous filters. Therefore, the Activity LEDs in a
given band display the overall activity in that band, and are not necessarily
indicative of the action of any single filter at that moment.
OPERATING THE DNS1500
Introduction
The DNS1500 divides a signal into a large number of well defined bands.
Sophisticated digital filters analyse each of these bands and suppress the noise
independently in each. The innovative design of this filter bank allows you to
control the DNS1500 using relatively few front panel controls.
Bypass
You can route the input directly to the output by pressing the Bypass button. This
allows you to audition the signal before and after processing. The signal latency
is not affected by the Bypass state.
Channel Selector
Your first job will be to identify the channel(s) that include(s) the unwanted noise.
Press the CHAN 1 button if you wish to process channel 1 only. Press the CHAN
2 button if you wish to process channel 2 only. Press both if you wish to process
both channels.
When processing both channels, the DNS1500 uses the same parameter values
for each (as determined by the current settings of the front panel controls) but
responds to the audio in each channel independent of the audio in the other.
Range Selector
Next, you should identify the frequency range or ranges in which the noise lies.
You can press each of the Range Selector buttons individually, or combine them
to choose any one of six possible processing ranges:
Low 20Hz - 400Hz
Mid 200Hz - 6kHz
High 4kHz - maximum
Low + Mid 20Hz - 6kHz
Mid + High 200Hz - maximum
Full Range 20Hz - maximum
The maximum sample rate varies from 12kHz at 32kHz sample rate to
approximately 45kHz at 96kHz sample rate.
To select Low + Mid or Mid + High, press the appropriate two buttons
simultaneously, or in quick succession while the first is flashing. To select Full
Range, press the Low and High buttons simultaneously or in quick succession.
Selecting a range concentrates all of the filters within the DNS1500’s filter bank
across that part of the audio spectrum.

CASE STUDIES
The following case studies describe just three of the ways in which you can use
the DNS1500. You can apply the DNS1500 equally to recorded signals and to
‘live’ signals at the point of recording or transmission.
1. SUPPRESSING TRAFFIC NOISE
The DNS1500 can suppress background noises such as road traffic, aircraft, air
conditioning, wind, rain, and many other common soundstage, location, and OB
problems that contaminate audio. If your signal exhibits any of these problems,
you can suppress them as follows.
First, identify the frequency range(s) in which the noise lies.
You should be able to do this by listening to the problem. However, if this proves
difficult, you can use the following method.
It is not important that you find the perfect settings at the first attempt. In
particular, you will be able to refine your Level and Band Gain settings once you
have found the correct range.
Begin as follows:
Select the correct channel(s)
Ensure that the DNS1500 is not in Bypass
Select Full Range
• Set all six Band Gain controls to -24dB
• Raise the Level control until the noise disappears
At this point you have determined an approximate setting for the Level. This is
necessary for determining the range but it is likely that you will refine this later in
the procedure.
When the Level is close to the ideal setting, you should see the Activity LEDs
flicker in response to the signal content.
Now continue as follows:
• Raise the Band Gain controls to 0dB (no processing occurs)
• Adjust the Band Gain controls to suppress the noise
You should always attempt to suppress the noise with the minimum of damage to
the desired signal.
In all likelihood, you will find that the leftmost Band Gain controls are pulled down
significantly, whereas the central and rightmost are close to 0dB. This tells you
that the problem does not lie in the upper frequencies, so you should use the
Range Selector to select Low+Mid. Then repeat the steps marked “•”.
If you now find that you are using all six faders in similar fashion, it is likely that
the noise is distributed across the entire Low+Mid range. However, if the
suppression is still heavily biased towards the left hand faders, you should now
select the Low range alone and repeat the procedure.
If you select Low alone and cannot suppress the noise, it is probable that there is
considerable noise energy in the Mid band, so you should return to using
Low+Mid ranges.
For many problems such as traffic noise, the noise will lie primarily in the range
50Hz - 1.5kHz. In this case, Low+Mid will be the correct choice.
Second, optimise the Level control.
Listening carefully to the audio, refine the Level setting so that the noise is
correctly identified without introducing audible artefacts. If this proves difficult,
you can return the Band Gain controls to -24dB for this stage.
The DNS1500 takes a short period to “settle” after moving the Level control
(especially in the lower ranges) so you should not adjust it rapidly.
Third, refine the Band Gain controls for optimum suppression.
Set all six Band Gain controls to 0dB. Now increase and decrease the Gain in
each band separately while listening to the effect that each has on the noise. This
will identify the bands that contain the majority of the noise. (Do not be alarmed if
all six bands contain significant noise. This is not unusual.)
Let’s assume that the
greatest improvement occurs
when you reduce the Gain in
bands 3 and 4. This
suggests that the noise is
concentrated in an
approximate range of 200Hz
to 1kHz. You should now find
the optimum positions for all
six faders. The greatest cuts
will lie in bands 3 and 4,
whereas bands 1, 2, 5 and 6
should remain as close to
0dB as possible to ensure
that minimal signal damage
occurs in the bands that do
not contain much noise.
The final configuration may
look like this:

CASE STUDIES
The following case studies describe just three of the ways in which you can use
the DNS1500. You can apply the DNS1500 equally to recorded signals and to
‘live’ signals at the point of recording or transmission.
1. SUPPRESSING TRAFFIC NOISE
The DNS1500 can suppress background noises such as road traffic, aircraft, air
conditioning, wind, rain, and many other common soundstage, location, and OB
problems that contaminate audio. If your signal exhibits any of these problems,
you can suppress them as follows.
First, identify the frequency range(s) in which the noise lies.
You should be able to do this by listening to the problem. However, if this proves
difficult, you can use the following method.
It is not important that you find the perfect settings at the first attempt. In
particular, you will be able to refine your Level and Band Gain settings once you
have found the correct range.
Begin as follows:
Select the correct channel(s)
Ensure that the DNS1500 is not in Bypass
Select Full Range
• Set all six Band Gain controls to -24dB
• Raise the Level control until the noise disappears
At this point you have determined an approximate setting for the Level. This is
necessary for determining the range but it is likely that you will refine this later in
the procedure.
When the Level is close to the ideal setting, you should see the Activity LEDs
flicker in response to the signal content.
Now continue as follows:
• Raise the Band Gain controls to 0dB (no processing occurs)
• Adjust the Band Gain controls to suppress the noise
You should always attempt to suppress the noise with the minimum of damage to
the desired signal.
In all likelihood, you will find that the leftmost Band Gain controls are pulled down
significantly, whereas the central and rightmost are close to 0dB. This tells you
that the problem does not lie in the upper frequencies, so you should use the
Range Selector to select Low+Mid. Then repeat the steps marked “•”.
If you now find that you are using all six faders in similar fashion, it is likely that
the noise is distributed across the entire Low+Mid range. However, if the
suppression is still heavily biased towards the left hand faders, you should now
select the Low range alone and repeat the procedure.
If you select Low alone and cannot suppress the noise, it is probable that there is
considerable noise energy in the Mid band, so you should return to using
Low+Mid ranges.
For many problems such as traffic noise, the noise will lie primarily in the range
50Hz - 1.5kHz. In this case, Low+Mid will be the correct choice.
Second, optimise the Level control.
Listening carefully to the audio, refine the Level setting so that the noise is
correctly identified without introducing audible artefacts. If this proves difficult,
you can return the Band Gain controls to -24dB for this stage.
The DNS1500 takes a short period to “settle” after moving the Level control
(especially in the lower ranges) so you should not adjust it rapidly.
Third, refine the Band Gain controls for optimum suppression.
Set all six Band Gain controls to 0dB. Now increase and decrease the Gain in
each band separately while listening to the effect that each has on the noise. This
will identify the bands that contain the majority of the noise. (Do not be alarmed if
all six bands contain significant noise. This is not unusual.)
Let’s assume that the
greatest improvement occurs
when you reduce the Gain in
bands 3 and 4. This
suggests that the noise is
concentrated in an
approximate range of 200Hz
to 1kHz. You should now find
the optimum positions for all
six faders. The greatest cuts
will lie in bands 3 and 4,
whereas bands 1, 2, 5 and 6
should remain as close to
0dB as possible to ensure
that minimal signal damage
occurs in the bands that do
not contain much noise.
The final configuration may
look like this:

Page 14 Page 15
2. SUPPRESSING TAPE HISS
The DNS1500 can suppress the tape hiss that mars many older recordings. It will
also improve the signal/noise ratio of dialogue tapes that have been poorly
copied as well as those that are many generations old.
First, identify the frequency range(s) in which the noise lies.
You should follow the procedure laid down in case 1 to determine the range(s) in
which the problem lies. For most instances of tape hiss, you will find that the
Mid+High ranges are most appropriate. In a few cases you may find that the
High range alone is most suitable. It is not as common to require suppression in
the Low range because hiss is usually less prominent at lower frequencies, and it
may also be masked by the genuine audio in the range.
Second, optimise the Level control.
To determine the correct Level, you should again follow the procedure described
in case 1.
Third, refine the Band Gain controls for optimum suppression.
As in case 1, you should start with all six Band Gain controls at 0dB. You should
then increase and decrease each control individually to find the bands that
contribute most hiss to the signal. Because tape hiss often exhibits a “white”
profile at Mid and High frequencies, you may find that satisfactory results are
achieved with the Band Gain controls set in a horizontal line.
However, hiss is generally
less annoying at very high
audio frequencies.
Consequently, you may be
able to reduce the amount of
processing in the uppermost
bands. This will help to
ensure that any low
amplitude signal components
lying at high frequencies
(which provide much of the
“air”, “ambience” or “life” in a
signal) are passed with little
or no attenuation.
The final configuration may
look like this:
3. SUPPRESSING EXCESSIVE REVERBERATION
In many situations, the DNS1500 can suppress excessive reverberation. This can
be useful in TV production when you need to match the audio from a large
recording studio or soundstage to visual images set in a small room or other
enclosed space. Suppressing reverberation can also be beneficial in increasing
the intelligibility of poor dialogue recordings.
The method used to suppress reverberation is quite different from that applied in
cases 1 and 2, and is as follows:
First, set the range in which the reverberation lies.
In general, reverberant spaces include soft materials that absorb high
frequencies more rapidly than middle and lower frequencies. Even bare rooms
with hard walls include these materials: they are the actors.
Consequently, you will find that Low+Mid is almost always the most appropriate
combination of ranges for suppressing reverberation.
Second, set the Band Gain controls.
You should set all six Band Gain controls to -24dB. This will ensure that (provided
the other controls are set correctly) the DNS1500 processes the “tails” of the
sound without adversely affecting the desired signal.
Third, optimise the Level control.
Starting at its minimum
position (-80dB) increase the
Level control slowly. At some
point before full noise
suppression becomes
apparent, you will hear the
tails of louder sounds
become truncated.
You can adjust the amount of
truncation of the reverb
using the Level control rather
than the Band Gain controls.
The final configuration may
look like this:

Page 14 Page 15
2. SUPPRESSING TAPE HISS
The DNS1500 can suppress the tape hiss that mars many older recordings. It will
also improve the signal/noise ratio of dialogue tapes that have been poorly
copied as well as those that are many generations old.
First, identify the frequency range(s) in which the noise lies.
You should follow the procedure laid down in case 1 to determine the range(s) in
which the problem lies. For most instances of tape hiss, you will find that the
Mid+High ranges are most appropriate. In a few cases you may find that the
High range alone is most suitable. It is not as common to require suppression in
the Low range because hiss is usually less prominent at lower frequencies, and it
may also be masked by the genuine audio in the range.
Second, optimise the Level control.
To determine the correct Level, you should again follow the procedure described
in case 1.
Third, refine the Band Gain controls for optimum suppression.
As in case 1, you should start with all six Band Gain controls at 0dB. You should
then increase and decrease each control individually to find the bands that
contribute most hiss to the signal. Because tape hiss often exhibits a “white”
profile at Mid and High frequencies, you may find that satisfactory results are
achieved with the Band Gain controls set in a horizontal line.
However, hiss is generally
less annoying at very high
audio frequencies.
Consequently, you may be
able to reduce the amount of
processing in the uppermost
bands. This will help to
ensure that any low
amplitude signal components
lying at high frequencies
(which provide much of the
“air”, “ambience” or “life” in a
signal) are passed with little
or no attenuation.
The final configuration may
look like this:
3. SUPPRESSING EXCESSIVE REVERBERATION
In many situations, the DNS1500 can suppress excessive reverberation. This can
be useful in TV production when you need to match the audio from a large
recording studio or soundstage to visual images set in a small room or other
enclosed space. Suppressing reverberation can also be beneficial in increasing
the intelligibility of poor dialogue recordings.
The method used to suppress reverberation is quite different from that applied in
cases 1 and 2, and is as follows:
First, set the range in which the reverberation lies.
In general, reverberant spaces include soft materials that absorb high
frequencies more rapidly than middle and lower frequencies. Even bare rooms
with hard walls include these materials: they are the actors.
Consequently, you will find that Low+Mid is almost always the most appropriate
combination of ranges for suppressing reverberation.
Second, set the Band Gain controls.
You should set all six Band Gain controls to -24dB. This will ensure that (provided
the other controls are set correctly) the DNS1500 processes the “tails” of the
sound without adversely affecting the desired signal.
Third, optimise the Level control.
Starting at its minimum
position (-80dB) increase the
Level control slowly. At some
point before full noise
suppression becomes
apparent, you will hear the
tails of louder sounds
become truncated.
You can adjust the amount of
truncation of the reverb
using the Level control rather
than the Band Gain controls.
The final configuration may
look like this:

Page 16 Page 17
SPECIFICATIONS
General
Power supply: 85–260VAC; 50–60Hz Power consumption: 20W
Overall dimensions: 70 x 230 x 285 mm Weight: 2.1kg (net); 3kg (gross)
Audio
I/O type: Digital PCM Sample rates: 32, 44.1, 48 kHz
I/O resolution: 24 bits Varispeed: approx. ±4%
Data formats: SPDIF or AES/EBU Processor power: 120 Mflops
Latency: <10 samples Process resolution: 40 bits
EMC REGULATIONS
In order to comply with EMC regulations, you must connect the DNS1500 using
metal-shelled connectors and good quality shielded cable suitable for digital
audio.
Declaration of conformity
Date of issue 1 October 2007
Equipment CEDAR DNS1500
Manufacturer CEDAR Audio Ltd
Address 20 Home End, Fulbourn, Cambridge CB21 5BS, UK
This is to certify that the aforementioned equipment, when used in accordance
with the instructions in this manual, fully conforms to the protection requirements
of the following EC Council Directives: on the approximation of the laws of the
member states relating to:
89/336/EEC Electromagnetic Compatibility
Applicable standards: EN 55103-1:1996
EN 55103-2:1996
73/23/EEC Low Voltage Equipment
Applicable standard: EN 60065:1998
E&OE.
The Company reserves the right to change specifications without notice.
Intentionally left blank

Page 16 Page 17
SPECIFICATIONS
General
Power supply: 85–260VAC; 50–60Hz Power consumption: 20W
Overall dimensions: 70 x 230 x 285 mm Weight: 2.1kg (net); 3kg (gross)
Audio
I/O type: Digital PCM Sample rates: 32, 44.1, 48 kHz
I/O resolution: 24 bits Varispeed: approx. ±4%
Data formats: SPDIF or AES/EBU Processor power: 120 Mflops
Latency: <10 samples Process resolution: 40 bits
EMC REGULATIONS
In order to comply with EMC regulations, you must connect the DNS1500 using
metal-shelled connectors and good quality shielded cable suitable for digital
audio.
Declaration of conformity
Date of issue 1 October 2007
Equipment CEDAR DNS1500
Manufacturer CEDAR Audio Ltd
Address 20 Home End, Fulbourn, Cambridge CB21 5BS, UK
This is to certify that the aforementioned equipment, when used in accordance
with the instructions in this manual, fully conforms to the protection requirements
of the following EC Council Directives: on the approximation of the laws of the
member states relating to:
89/336/EEC Electromagnetic Compatibility
Applicable standards: EN 55103-1:1996
EN 55103-2:1996
73/23/EEC Low Voltage Equipment
Applicable standard: EN 60065:1998
E&OE.
The Company reserves the right to change specifications without notice.
Intentionally left blank

Page 18 Page 19
6. WAIVER
The waiver by either party of a breach of the provisions hereof by the other shall not be construed as a
waiver of any succeeding breach of the same or other provisions, nor shall any delay or omission on the
part of either party to exercise any right that it may have under this Licence operate as a waiver of any
breach or default by the other party.
7. NOTICES
Any notices or instruction to be given hereunder shall be delivered or sent by first-class post or telecopier
to the other party, and shall be deemed to have been served (if delivered) at the time of delivery or (if
sent by post) upon the expiration of seven days after posting or (if sent by telecopier) upon the expiration
of twelve hours after transmission.
8. ASSIGNMENT AND SUB-LICENSING
The Licensee may at his discretion assign the System and in doing so shall assign this License its rights
and obligations to the purchaser who shall without reservation agree to be bound by this License. The
original Licensee and any subsequent Licensees shall be bound by the obligations of this License in
perpetuity.
9. LIMITATION OF LIABILITY
The Company‘s maximum liability under any claim including any claim in respect of infringement of the
intellectual property rights of any third party shall be, at the option of the Company either:
(a) return of a sum calculated as the price received for the System by the Company from its immediate
customer depreciated on a straight line basis over a one year write-off period; or
(b) repair or replacement of those components of the System that do not meet the warranties contained
within this Document.
The foregoing states the entire liability of the Company to the Licensee.
10. CONSEQUENTIAL LOSS
Even if the Company has been advised of the possibility of such damages, and notwithstanding anything
else contained herein the Company shall under no event be liable to the Licensee or to any other persons
for loss of profits or contracts or damage (whether direct or consequential) arising in connection with the
System or any modification, variation or enhancement thereof and including any documentation or data
provided by the Company or for any other indirect or consequential loss.
11. ENTIRE AGREEMENT
The Company shall not be liable to the Licensee for any loss arising in connection with any
representations, agreements, statements or undertakings made prior to the date of supply of the System
to the Licensee.
12. TERMINATION
This Licence may be terminated forthwith by the Company if the Licensee commits any material breach of
any terms of this License. Forthwith upon such termination the Company shall have immediate right of
access to the System for the purpose of removing it.
13. SEVERABILITY
Notwithstanding that the whole or any part of any provision of this Document may prove to be illegal or
unenforceable the other provisions of this Document and the remainder of the provision in question shall
remain in full force and effect.
14. HEADINGS
The headings to the Clauses are for ease of reference only and shall not affect the interpretation or
construction of this Document.
15. LAW
This Document shall be governed by and construed in accordance with English law and all disputes
between the parties shall be determined in England in accordance with the Arbitration Act 1950 and
1979.
LICENSE AND LIMITED WARRANTY
1. DEFINITIONS
In this Licence and Limited Warranty the following words and phrases shall bear the following meanings:
‘the Company’ is CEDAR Audio Limited of 20 Home End, Fulbourn, Cambridge CB21 5BS, UK;
‘the System’ means an instance of the DNS1500 sound-reprocessing system comprising hardware
and software held on non-volatile memory (‘firmware’) developed by the Company;
‘this Document’ means this License and Limited Warranty.
2. ISSUE AND USE OF THE SYSTEM
2.1 The terms and conditions of this Document are implicitly accepted by any person or body corporate
who shall at any time use or have access to the System, and are effective from the date of supply of
the System by CEDAR Audio Limited to its immediate customer.
2.2 The Company hereby grants to the Licensee and the Licensee agrees to accept a
non-exclusive right to use the System.
3. PROPERTY AND CONFIDENTIALITY
3.1 The System contains confidential information of the Company and all copyright, trade marks, trade
names, styles and logos and other intellectual property rights in the System including all
documentation and manuals relating thereto are the exclusive property of the Company. The
Licensee acknowledges that all such rights are the property of the Company and shall not question
or dispute the ownership of any such rights nor use or adopt any trading name or style similar to
that of the Company.
3.2 The Licensee shall not attempt to reverse engineer, modify, copy, merge or transcribe the whole or
any part of the System or any information or documentation relating thereto.
3.3 The Licensee shall take all reasonable steps to protect the confidential information and intellectual
property rights of the Company.
4. LIMITED WARRANTY AND POST-WARRANTY OBLIGATIONS
4.1 The Company warrants that the System will perform substantially in accordance with the
appropriate section of its accompanying product manual for a period of one year from the date of
supply to the Company‘s immediate customers.
4.2 The Company will make good at its own expenses by repair or replacement any defect or failure
that develops in the System within one year of supply to the Company‘s immediate customer.
4.3 The Company shall have no liability to remedy any defect, failure, error or malfunction that arises as
a result of any improper use, operation or neglect of the System, or any attempt to repair or modify
the System by any person other than the Company or a person appointed with the Company‘s prior
written consent.
4.4 In the case of any defect or failure in the System occurring more than twelve months after its supply
to the Company‘s immediate customer the Company will at its option and for a reasonable fee make
good such defect or failure by repair or replacement (at the option of the Company) subject to the
faulty equipment having first been returned to the Company. The Company will use reasonable
efforts to return repaired or replacement items promptly, all shipping, handling and insurance costs
being for the account of the Licensee.
4.5 The above undertakings 4.1 to 4.4 are accepted by the Licensee in lieu of any other legal remedy in
respect of any defect or failure occurring during the said period and of any other obligations or
warranties expressed or implied including but not limited to the implied warranties of saleability and
fitness for a specific purpose.
4.6 The Licensee hereby acknowledges and accepts that nothing in this Document shall impose upon
the Company any obligation to repair or replace any item after a time when it is no longer produced
or offered for supply by the Company or which the Company certifies has been superseded by a
later version or has become obsolete.
5. FORCE MAJEURE
The Company shall not be liable for any breach of its obligations hereunder resulting from causes beyond
its reasonable control including, but not limited to, fires, strikes (of its own or other employees),
insurrection or riots, embargoes, container shortages, wrecks or delays in transportation, inability to
obtain supplies and raw materials, or requirements or regulations of any civil or military authority.

Page 18 Page 19
6. WAIVER
The waiver by either party of a breach of the provisions hereof by the other shall not be construed as a
waiver of any succeeding breach of the same or other provisions, nor shall any delay or omission on the
part of either party to exercise any right that it may have under this Licence operate as a waiver of any
breach or default by the other party.
7. NOTICES
Any notices or instruction to be given hereunder shall be delivered or sent by first-class post or telecopier
to the other party, and shall be deemed to have been served (if delivered) at the time of delivery or (if
sent by post) upon the expiration of seven days after posting or (if sent by telecopier) upon the expiration
of twelve hours after transmission.
8. ASSIGNMENT AND SUB-LICENSING
The Licensee may at his discretion assign the System and in doing so shall assign this License its rights
and obligations to the purchaser who shall without reservation agree to be bound by this License. The
original Licensee and any subsequent Licensees shall be bound by the obligations of this License in
perpetuity.
9. LIMITATION OF LIABILITY
The Company‘s maximum liability under any claim including any claim in respect of infringement of the
intellectual property rights of any third party shall be, at the option of the Company either:
(a) return of a sum calculated as the price received for the System by the Company from its immediate
customer depreciated on a straight line basis over a one year write-off period; or
(b) repair or replacement of those components of the System that do not meet the warranties contained
within this Document.
The foregoing states the entire liability of the Company to the Licensee.
10. CONSEQUENTIAL LOSS
Even if the Company has been advised of the possibility of such damages, and notwithstanding anything
else contained herein the Company shall under no event be liable to the Licensee or to any other persons
for loss of profits or contracts or damage (whether direct or consequential) arising in connection with the
System or any modification, variation or enhancement thereof and including any documentation or data
provided by the Company or for any other indirect or consequential loss.
11. ENTIRE AGREEMENT
The Company shall not be liable to the Licensee for any loss arising in connection with any
representations, agreements, statements or undertakings made prior to the date of supply of the System
to the Licensee.
12. TERMINATION
This Licence may be terminated forthwith by the Company if the Licensee commits any material breach of
any terms of this License. Forthwith upon such termination the Company shall have immediate right of
access to the System for the purpose of removing it.
13. SEVERABILITY
Notwithstanding that the whole or any part of any provision of this Document may prove to be illegal or
unenforceable the other provisions of this Document and the remainder of the provision in question shall
remain in full force and effect.
14. HEADINGS
The headings to the Clauses are for ease of reference only and shall not affect the interpretation or
construction of this Document.
15. LAW
This Document shall be governed by and construed in accordance with English law and all disputes
between the parties shall be determined in England in accordance with the Arbitration Act 1950 and
1979.
LICENSE AND LIMITED WARRANTY
1. DEFINITIONS
In this Licence and Limited Warranty the following words and phrases shall bear the following meanings:
‘the Company’ is CEDAR Audio Limited of 20 Home End, Fulbourn, Cambridge CB21 5BS, UK;
‘the System’ means an instance of the DNS1500 sound-reprocessing system comprising hardware
and software held on non-volatile memory (‘firmware’) developed by the Company;
‘this Document’ means this License and Limited Warranty.
2. ISSUE AND USE OF THE SYSTEM
2.1 The terms and conditions of this Document are implicitly accepted by any person or body corporate
who shall at any time use or have access to the System, and are effective from the date of supply of
the System by CEDAR Audio Limited to its immediate customer.
2.2 The Company hereby grants to the Licensee and the Licensee agrees to accept a
non-exclusive right to use the System.
3. PROPERTY AND CONFIDENTIALITY
3.1 The System contains confidential information of the Company and all copyright, trade marks, trade
names, styles and logos and other intellectual property rights in the System including all
documentation and manuals relating thereto are the exclusive property of the Company. The
Licensee acknowledges that all such rights are the property of the Company and shall not question
or dispute the ownership of any such rights nor use or adopt any trading name or style similar to
that of the Company.
3.2 The Licensee shall not attempt to reverse engineer, modify, copy, merge or transcribe the whole or
any part of the System or any information or documentation relating thereto.
3.3 The Licensee shall take all reasonable steps to protect the confidential information and intellectual
property rights of the Company.
4. LIMITED WARRANTY AND POST-WARRANTY OBLIGATIONS
4.1 The Company warrants that the System will perform substantially in accordance with the
appropriate section of its accompanying product manual for a period of one year from the date of
supply to the Company‘s immediate customers.
4.2 The Company will make good at its own expenses by repair or replacement any defect or failure
that develops in the System within one year of supply to the Company‘s immediate customer.
4.3 The Company shall have no liability to remedy any defect, failure, error or malfunction that arises as
a result of any improper use, operation or neglect of the System, or any attempt to repair or modify
the System by any person other than the Company or a person appointed with the Company‘s prior
written consent.
4.4 In the case of any defect or failure in the System occurring more than twelve months after its supply
to the Company‘s immediate customer the Company will at its option and for a reasonable fee make
good such defect or failure by repair or replacement (at the option of the Company) subject to the
faulty equipment having first been returned to the Company. The Company will use reasonable
efforts to return repaired or replacement items promptly, all shipping, handling and insurance costs
being for the account of the Licensee.
4.5 The above undertakings 4.1 to 4.4 are accepted by the Licensee in lieu of any other legal remedy in
respect of any defect or failure occurring during the said period and of any other obligations or
warranties expressed or implied including but not limited to the implied warranties of saleability and
fitness for a specific purpose.
4.6 The Licensee hereby acknowledges and accepts that nothing in this Document shall impose upon
the Company any obligation to repair or replace any item after a time when it is no longer produced
or offered for supply by the Company or which the Company certifies has been superseded by a
later version or has become obsolete.
5. FORCE MAJEURE
The Company shall not be liable for any breach of its obligations hereunder resulting from causes beyond
its reasonable control including, but not limited to, fires, strikes (of its own or other employees),
insurrection or riots, embargoes, container shortages, wrecks or delays in transportation, inability to
obtain supplies and raw materials, or requirements or regulations of any civil or military authority.

Page 20
CEDAR DNS1500
Designed and manufactured by
CEDAR Audio Ltd
20 Home End
Fulbourn
Cambridge CB21 5BS
United Kingdom
www.cedaraudio.com
[e-mail]
Serial number:
Inspected:
QC Engineer:
interstage
Phistersvej 31, 2900 Hellerup, Danmark
Telefon [phone], fax [phone]
www.interstage.dk
-pro audio with a smile