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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:

Содержание DNS1500

Страница 1: ...MANUAL 2007 CEDAR Audio Ltd Manual version 1 00 September 2007 DNS1500 dialogue noise suppressor interstage Phistersvej 31 2900 Hellerup Danmark Telefon 3946 0000 fax 3946 0040 www interstage dk pro audio with a smile ...

Страница 2: ...ating 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 ...

Страница 3: ...ating 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 ...

Страница 4: ...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 ma...

Страница 5: ...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 ma...

Страница 6: ... 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 car...

Страница 7: ... 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 car...

Страница 8: ...ented 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 ...

Страница 9: ...ented 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 ...

Страница 10: ...he 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 f...

Страница 11: ...he 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 f...

Страница 12: ...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 ...

Страница 13: ...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 ...

Страница 14: ...mplitude 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...

Страница 15: ...mplitude 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...

Страница 16: ...table 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 approximati...

Страница 17: ...table 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 approximati...

Страница 18: ...em 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 CE...

Страница 19: ...em 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 CE...

Страница 20: ...udio Ltd 20 Home End Fulbourn Cambridge CB21 5BS United Kingdom www cedaraudio com info cedaraudio com Serial number Inspected QC Engineer interstage Phistersvej 31 2900 Hellerup Danmark Telefon 3946 0000 fax 3946 0040 www interstage dk pro audio with a smile ...

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