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The Duo Series
declickle and auto dehiss
Version 1.2
19 September 2004
Copyright CEDAR Audio Ltd, © 2004
CEDAR is a registered trademark of CEDAR Audio Ltd
Duo, declickle and auto dehiss are trademarks of CEDAR Audio Ltd
E&OE, Subject to revision at the Company's sole discretion
interstage
Phistersvej 31, 2900 Hellerup, Danmark
Telefon 3946 0000, fax 3946 0040
www.interstage.dk
- pro audio with a smile
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Table of Contents
Related Manuals for Cedar Duo Series
Summary of Contents for Cedar Duo Series
- Page 1 19 September 2004 Copyright CEDAR Audio Ltd, © 2004 CEDAR is a registered trademark of CEDAR Audio Ltd Duo, declickle and auto dehiss are trademarks of CEDAR Audio Ltd E&OE, Subject to revision at the Company’s sole discretion interstage Phistersvej 31, 2900 Hellerup, Danmark Telefon 3946 0000, fax 3946 0040 www.interstage.dk...
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Page 3: Table Of Contents
Table Of Contents Table Of Contents Introducing the CEDAR Duos ................... 1 Specifications and CE Certificates..................2 Contact Information ....................... 4 Technical Support ......................5 Safety Instructions ......................6 Getting Started ......................7 Front Panel Indicators and Controls .................. 8 General Set-up and Connections .................. - Page 4 CEDAR Duo – declickle and auto dehiss This page left blank...
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Page 5: Introducing The Cedar Duos
CEDAR Duo declickle module CEDAR Duo auto dehiss module Thank you for purchasing this CEDAR Duo audio restoration module. It is one of a family of the world’s most advanced and most effective noise removal units, and it offers outstanding processing power and performance. -
Page 6: Specifications And Ce Certificates
CEDAR Duo – declickle and auto dehiss Specifications and CE Certificates General: Power supply: 85–260VAC; 50–60Hz I/O type: Digital PCM Power consumption: 15W (standby 1W) I/O resolution: 24 bits Overall dimensions: 45 x 483 x 240mm Sample rate: 30–100kHz Weight: 3kg (net); 4kg (gross) - Page 7 CEDAR Duo – declickle and auto dehiss Declaration of conformity: Date of issue: 1 April 2004 Equipment: CEDAR Duo Manufacturer: CEDAR Audio Ltd Address: 20 Home End, Fulbourn, Cambridge CB1 5BS, UK This is to certify that the aforementioned equipment, when used in accordance with the...
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Page 8: Contact Information
CEDAR Duo – declickle and auto dehiss Contact Information Headquarters: Address: CEDAR Audio Limited, 20 Home End, Fulbourn, Cambridge, CB1 5BS, United Kingdom Telephone and Fax: T: +44 1223 881771 F: +44 1223 881778 Email: support@cedaraudio.com USA Office: Address: CEDAR Audio USA, 43 Deerfield Road, Portland, ME 04101-1805, USA... -
Page 9: Technical Support
We hope that you will never need to read this page, but should you experience difficulties with your CEDAR Duo, please contact your local dealer or CEDAR office. Alternatively, you may send an email to support@cedaraudio.com. In either case, please provide the following details: ■... -
Page 10: Safety Instructions
CEDAR Duo – declickle and auto dehiss Safety Instructions Read these instructions, follow them, and save them for future reference. ■ 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. -
Page 11: Getting Started
CEDAR Duo – declickle and auto dehiss Getting Started Unpacking Unpack the Duo carefully. Save the carton and all packing materials since you may need them to transport the unit in the future. In addition to the Duo and the packaging, the carton should contain the following: ■... -
Page 12: Front Panel Indicators And Controls
CEDAR Duo – declickle and auto dehiss Front Panel Indicators and Controls Power switch and power LEDs ■ When OFF, the Duo is in standby mode. ■ When ON, the Duo is powered up and operational. The power status is reported by the power LEDs on the right of the front panel. -
Page 13: General Set-Up And Connections
CEDAR Duo – declickle and auto dehiss General Set-up and Connections Basic Set-up When you switch on the Duo, it will present one of the following screens to you. These are the Main screens for declickle and auto dehiss, respectively. To set up the unit and access a number of less often required parameters, press the MENU option. - Page 14 CEDAR Duo – declickle and auto dehiss These offer five or six options, depending upon the product. Press the desired option to access the screen of your choice. ■ SETUP: Enter the set-up and reset screen ■ AUDIO I/O: Enter the audio set-up and monitoring screen ■...
- Page 15 CEDAR Duo – declickle and auto dehiss ■ Serial number Reports the serial number of this unit. Audio I/O ■ Output Press the OUTPUT option repeatedly to cycle through 16, 18, 20 and 24-bit output wordlength options. You should choose the option most suitable for the next device in the audio chain.
- Page 16 CEDAR Duo – declickle and auto dehiss ■ Digital AES/EBU format audio data The AES/EBU format is used by professional digital audio devices. You should connect the AES/EBU output from your source to the AES/EBU input of the Duo using a single cable terminated with an XLR plug.
- Page 17 ■ DSPn: NN NN mm This provides information about each of the SHARC processors within the Duo. ■ NN NN: These are status codes that should be reported to CEDAR Audio in the event of a failure ■ mm: This field reports two messages, "OK" or "ERROR"...
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Page 18: Memories
CEDAR Duo – declickle and auto dehiss Memories Your Duo offers 99 memory locations in addition to the current workspace. The workspace is volatile, so it is useful to be able to store and recall set-ups. You do so using the MEMORY screens, as follows. - Page 19 CEDAR Duo – declickle and auto dehiss ■ CANCEL: Exits from this screen without making any changes, and returns you to the MEMORY screen ■ DONE: Saves the name changes, exits from this screen, and returns you to the MEMORY...
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Page 20: Remote Control (Midi) Implementation
CEDAR Duo – declickle and auto dehiss Remote Control (MIDI) Implementation Standard MIDI control messages may be used to control all the Duos' audio parameters. The only system parameters that can be altered from the front panel but which cannot be edited via MIDI are the display contrast and the MIDI channel. - Page 21 CEDAR Duo – declickle and auto dehiss MIDI Controller Numbers (Auto dehiss only) Command Comments ■ 0-63 = Left/Right Process mode ■ 64-127 = Mid & Side Level A 0-127 maps to -99.5dB to 0dB (left or mid) Level B 0-127 maps to -99.5dB to 0dB...
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Page 22: Declickle: Removing Impulsive Noises
CEDAR Duo – declickle and auto dehiss Declickle: Removing impulsive noises You will find all the parameters specific to declicking and decrackling on the Main screen: There are six options: ■ THRESH ■ MODEL ■ DETECT ■ L-R ■ MENU ■... - Page 23 CEDAR Duo – declickle and auto dehiss The model value ranges from 00 to 99 on an arbitrary scale, and the current values are displayed both numerically and on the horizontal bar-graphs. Detect Allows you to select the most appropriate detection mode for the material being processed. The options are: ■...
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Page 24: Declickle Tutorial
CEDAR Duo – declickle and auto dehiss Declickle tutorial Detect Your first job is to choose the correct detection mode for the material to be restored. Listen to the audio, and decide whether it contains well-defined clicks, whether it suffers from grungy clicks and crackle, or whether the problems lie somewhere between. -
Page 25: An Introduction To Click And Crackle Removal
CEDAR Duo – declickle and auto dehiss An Introduction to Click and Crackle Removal Clicks Clicks are impulsive noises of short duration. The simplest audio declicker is an attenuator which, at the precise moment that a click is detected, mutes the audio, thereby reducing the impact of the click. The minimum duration of the mute (actually a high speed fade-out and fade-in) is typically 2.5ms, and even a small... - Page 26 CEDAR Duo – declickle and auto dehiss The next stage is Linear Interpolation. Whereas Sample and Hold takes account of one good sample adjacent to the scratch, linear interpolation takes account of two adjacent good samples and the elapsed time between them. In this algorithm the corrupted data is replaced by a straight line joining the last good sample and the next available good sample.
- Page 27 CEDAR Duo – declickle and auto dehiss Modern interpolators are based on signal modelling. By analysing the signal over a region of several milliseconds the algorithm can build a model of the underlying signal and use the information to replace each click with an interpolation that fits this model.
- Page 28 CEDAR Duo – declickle and auto dehiss Various Forms of "Crackly" Signal Defects...
- Page 29 Declickle CEDAR's Declickle algorithm was born out of research into the dual problems of declicking and decrackling difficult signals such as those including overblown brass instruments, solo strings, and human singing. In attempting to solve these difficulties, our researchers discovered that a single, new algorithm yielded better results than applying separate declick and decrackle processes.
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Page 30: Auto Dehiss: Reducing Broadband Noise
CEDAR Duo – declickle and auto dehiss Auto dehiss: Reducing broadband noise Process Mode Auto dehiss offers four combinations of processing modes: ■ Noise detection mode may be either Auto or Manual In auto mode, the Duo processor automatically determines the noise level contained within the signal, whereas in manual mode the noise level is set by the user. - Page 31 CEDAR Duo – declickle and auto dehiss Auto Mode There are six options: ■ BIAS ■ LF BIAS ■ ATTEN ■ L-R / M-S (shown above in L-R mode) ■ MENU ■ AUTO-OFF Bias (dB) The Bias control allows you to tune the automatic algorithm for different applications and tastes;...
- Page 32 CEDAR Duo – declickle and auto dehiss L-R / M-S ■ Select which channel or channels you are adjusting by repeatedly pressing the L-R / M-S button. ■ Toggle between Left/Right and Mid & Side modes by pressing and holding this button for three seconds or more.
- Page 33 CEDAR Duo – declickle and auto dehiss If the Level is too high, auto dehiss will treat some low-level signal as if it was noise and attenuate it. This may make the signal sound muffled. LF Bias (dB at 0Hz) The LF Bias control allows fine control of the algorithm below 5kHz.
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Page 34: Auto Dehiss Tutorials
If necessary, you should pass the signal through the Duo declickle processor or other CEDAR declick and decrackle processes before applying the auto dehisser. Manual Mode (L-R channel mode selected) Set the auto dehiss processor in MANL (manual) mode, and ensure that the MANL-OFF control is in the MANL position. - Page 35 CEDAR Duo – declickle and auto dehiss Switch the processing off, and listen to the source material. Does the noise appear to be present at all frequencies? If not, is it predominantly high-frequency (hiss) or low-frequency (rumble)? If the former, turn the processing on again, and reduce the LF Bias. This will reduce the Level below 5kHz, and reduce the amount of noise detected at these frequencies.
- Page 36 CEDAR Duo – declickle and auto dehiss Bias Tutorial Since the auto dehisser is operating in Auto mode, it should in most cases be unnecessary to adjust the Bias. However, there are occasions where you may wish to bias the operation of the unit toward identifying greater or lesser amounts of noise in the signal (hence the name).
- Page 37 CEDAR Duo – declickle and auto dehiss Decrease the amount of attenuation from -40.0 to 0.0, at which point you will hear that the processed signal is identical to the unprocessed signal. This is because the Attenuation control is limiting the amount of noise removal to 0dB - i.e. there is no effect.
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Page 38: A Short History Of Noise Reduction
CEDAR Duo – declickle and auto dehiss A Short History of Noise Reduction It would be best to describe first what we mean by the term 'broadband' noise, defining it to be an effect that adds (or subtracts) a random amplitude at all times to (or from) all frequencies within the audio spectrum. - Page 39 CEDAR Duo – declickle and auto dehiss An Expander is another device with a threshold control, but unlike the gate, this applies a progressive gain reduction, the amount of which is determined by the user. For example, if a signal drops 3dB below the threshold, the Expander may reduce the signal volume by 6dB, 12dB, or any other figure, depending upon the expansion ratio.
- Page 40 Perfect restoration of hissy audio is theoretically impossible, but there are many techniques that CEDAR has developed to reduce the audible effect of hiss with as few side effects as possible. Our earlier dehissers, such as the DH-1, DH-2, DHX, Dehiss-2 and Dehiss-3 (which were optimised for reasonably consistent broadband noises such as tape-hiss) were sometimes called ‘auto dehissers’...
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Page 41: Licence And Limited Warranty
In this Licence and Limited Warranty the following words and phrases shall bear the following meanings: 'the Company' means CEDAR Audio Limited of 20 Home End, Fulbourn, Cambridge CB1 5BS, 'the System' means an instance of the sound-reprocessing system comprising hardware and software held on EPROM/FLASH memory ('firmware') developed by the Company and with respect to the software any updates or replacements thereof;... - Page 42 CEDAR Duo – declickle and auto dehiss 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.
- Page 43 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;...
- Page 44 CEDAR Duo – declickle and auto dehiss Serial Number: Inspected by: Date: Manufactured by: CEDAR Audio Ltd 20 Home End Fulbourn Cambridge CB1 5BS Web: www.cedaraudio.com Email: info@cedaraudio.com Tel: +44 1223 881771 interstage Phistersvej 31, 2900 Hellerup, Danmark Telefon 3946 0000, fax 3946 0040 www.interstage.dk...