Cedar CR-1 De-Crackler User manual

CEDAR
Professional Hardware Systems
CR-1 De-Crackler
Digital Audio Restoration System
SERIES 2
OWNER'S MANUAL
© 1994 CEDAR Audio Ltd. Written by Gordon Reid
CR- 1 SERIES 2: Rev.02 Ver.3.06 Page - 1
October 11, 1995

TABLE OF CONTENTS
TABLE OF CONTENTS .............................................................................................2
INTRODUCTION ........................................................................................................3
THE BACKGROUND TO CRACKLE REMOV AL..............................................4
SAFETY INSTRUCTIONS .........................................................................................5
SET UP ...........................................................................................................................7
Unpacking and Inspection .............................................................................7
Installation site ..................................................................................................7
Rack Mounting .................................................................................................7
Free Standing use .............................................................................................7
CONNECTIONS ..........................................................................................................8
Before Connection ...........................................................................................8
Power Connections ..........................................................................................8
Signal Lead Connections ................................................................................8
Other Connections .......................................... .. ...............................................10
SAMPLE INSTALLATION IDEAS......................................................................... 11
A GUIDE TO RESTORATION PROCESSING ...... .. .............................................12
FRONT PANEL INDICATORS AND CONTROLS .............................................14
QUICK TOUR .................................................. .. ...........................................................16
W ARMST ART AND COLDST ART ........................................................................17
OPERATING THE CEDAR CR-l SERIES 2...........................................................18
Dedicated Controls ..................... .. ..................................................................18
PAGES ...............................................................................................................20
Control Page ......................................................................................... 21
Input/Output Control Page ..............................................................24
Remote Control ....................................................................................28
Status Page ............................................................................................29
Sta
tus Indica tors...................................................................................29
NOTES AND HINTS TO USERS
REMOTE CONTROL PROTOCOLS .......................................................................33
RS232...................................................................................................................33
MID!.................................................................................................................... 35
SELF TEST MODE ......................................................................................................36
CR- 1 SERIES 2: Rev.02 Ver.3.06
Page-2
October
10, 1995

INTRODUCTION
Thank you for purchasing the CEDAR CR-1 De-Crackler. The original CR-1 was the
world's first real-time dedicated digital de-crackler, offering unique buzz removal
and distortion reduction facilities. The
CR-1 SERIES 2 offers even greater
processing power and performance -power exceeding that obtained using digital
signal processors (DSPs) installed
in desk-top (or larger) computer systems
(excepting, of course, the CEDAR Production Systems.
The
CR-1 SERIES 2 is designed for professional use, although it will work perfectly
well
in a domestic environment, and its features include the following:
• The latest 'SERIES-2' CEDAR hardware.
• Digital Audio interfaces conforming
to tile AES/EBU and SP-DIF standards.
• 24-bit input and output resolution when using AES/EBU interfaces
• Three sample rates supported
on digital inputs: 32kHz, 44.1 kHz and 48kHz
• Two sample rates supported
on analogue inputs: 44.1 kHz and 48kHz
• Balanced analogue inputs and outputs for connection to professional
analogue equipment.
• ADC and DAC converters using the latest
64x over-sampling /1- I. (Delta-
Sigma) technology.
• >103dB dynamic range
AID and >93dB dynamic range D/A
• Mountable in a 19" EIA rack.
• Remote control via MIDI and RS232 interfaces.
• SMPTE/EBU timecode capabilities via optional upgrade
• Input and output LED bar-graph
VU meters.
• Twin
40 -bit 'I'Ioating point DSP processors delivering 50MFIops to handle the
most complex audio processing requirements.
• High levels of artificial intelligence designed into the
CR-1 program
algorithms making
it extremely simple to use.
CR- 1 SERIES 2: Rev.02 Ver.3.06 Page - 3
October
10 . 1995

THE BACKGROUND TO CRACKLE REMOVAL
The term 'crackle' is often used to describe many different audio phenomena -low
level high density ticks, surface noise, buzz, and some forms of amplitude
distortion·.
Fortunately, these degradations exhibit quite similar audio characteristics, and
we
have found that a single process -the unique CEDAR 'Split & Recombine' -is
capable of removing crackle, removing buzz, and significantly reducing many
instances of distortion.
The
CR-1 has been designed to perform real-time crackle removal, buzz removal,
and distortion reduction (which, for the remainder of this manual we shall refer to as
simply 'crackle removal').
The operation of the
CR-1 is totally digital, and any signal presented to the
analogue inputs is internally converted to a suitable digital format by the analogue-
to-digital converter (ADC). Following crackle removal the processed signal
is then
converted back from digital format
to analogue by the internal digital-to-analogue
converter (DAC).
For use with records, films, video, and tape,
no other device offers the power,
facilities, or accuracy of the
CR-1 SERIES 2.
• Distortion comes
in two families; amplitude-based distortions and time-
based distortions. Examples of the former are microphone diaphragm
grounding and overdriven mixer inputs; examples of the latter include tape
over-modulation and compression.
CR -1 SERIES 2: Rev. 02 Ver.3.06
Page-4
October 10, 1995

SAFETY INSTRUCTIONS
CAUTION:
1. Read all of these instructions
All safety and operating instructions should be read before the CR-1 SERIES
2 is operated.
2. Save these instructions for future reference.
3. Follow all warnings and instructions.
4. Water and Moisture
The CR-1 SERIES 2 should not be used near water, and must not be
exposed to rain or moisture. If the CR-1 is brought directly from a cold
environment into a warm one, moisture may condense inside the unit. This,
in itself, will not damage the CR-1 , but may cause hazardous electrical
shorting to occur. This could severely damage the CR-1 and even cause
danger to life.
ALWAYS allow time for the CR-1 to naturally reach ambient
temperatures before connecting the mains power.
5. Mounting
The CR-1 SERIES 2 should be carefully mounted in a 19" EIA rack, or
placed on a flat, stable surface. If used on a cart or free stand, care should
be taken when moved: uneven surfaces or excessive force may cause cart
and CR-1 to overturn. Do not position the CR-1 in a place subject to strong
sunlight, excessive dust, mechanical vibration or periodic shocks.
6. Wall or Ceiling Mounting
The CR-1 SERIES 2 has not been designed for mounting directly to walls or
ceilings.
7. Ventilation
Good air circulation is essential to prevent internal heat built-up within the
CR -1 SERIES 2. The CR-1 should be situated so that its position does not
interfere with proper ventilation. The CR-1 should not be placed in any
situation which impedes the flow of air through the vents at the front and
rear. Do not place the CR-1
on a soft surface.
8. External Heat Sources
The CR-1 SERIES 2 should be installed away from significant heat sources
such as radiators, and (if possible) away from other audio devices such as
amplifiers that produce large amounts of heat. Installation
in racks with
devices such as signal processors or tape machines should not be a
problem.
CR- 1 SERIES 2: Rev.02 Ver.3. 06
Page - 5
October 10, 1995

9. Power Sources
The CR-1 SERIES 2 features an auto-switching power supply which will
work safely on any mains supply
in the ranges 95v/130v and 190v/260v,
50Hz or 60Hz AC only.
You should never attempt to modify or adjust the internal power
supply
in any way. It contains no user serviceable parts.
10. Grounding or Polarisation
The CR-1 SERIES 2 should always be grounded (or 'earthed').
11. Power Cord Protection
Power connectors should be routed so that they will not be walked on or
pinched.
12. Extended Periods of Non-Use
The CR-1 SERIES 2 is not disconnected from the mains power as long as it
is connected to the wall outlet, even if the unit itself has been switched off.
Therefore, if the
CR-1 is not to be used for an extended period of time,
unplug the unit from the wall. Pull the connector out by the plug, never by the
cord itself.
13.
Cleaning
Clean only with a dry cloth. NEVER use liquid cleaners such as alcohol or
benzene on the
CR-1 SERIES 2. NEVER use abrasive pads on the CR-1.
14. Damage Requiring Service
The CR-1 SERIES 2 should be returned to qualified service personnel when:
• objects have fallen into the unit
• liquid has been spilled into the unit
• the unit has been exposed to rain
• the unit fails to function or appears to operate abnormally
• the unit has been dropped,
or the case damaged.
15.
Servicing
The user should not attempt to service the CR-1 SERIES 2 beyond the
instructions contained
in the User's Manual. All other servicing should be
referred to qualified service personnel.
CR- 1 SERIES 2: Rev.02 Ver.3. 06
Page - 6
October 10. 1995

SETUP
1. UNPACKING AND INSPECTION
Be careful not to damage the CR-1 SERIES 2 during unpacking. Save the
carton and all packing materials since you may need them to transport the
CR-1 SERIES 2 in the future.
In addition to the packaging, the carton should contain the following:
• mains connection lead
• this manual
• two blanking plates
2. INSTALLATION SITE
The CR-1 SERIES 2 may be used in most areas, but to maintain reliability
and prolong operating life observe the following environmental
considerations:
• Nominal temperature should
be maintained between 5° and 35°
Centigrade (41 ° and 95° Fahrenheit).
• Relative humidity should be
in the range 30% to 60% non-
condensing.
• Strong magnetic fields should not exist nearby.
3. RACK MOUNTING
The CR-1 SERIES 2can be mounted in a standard 19" EIA rack.
4. FREE STANDING USE
The CR-1 SERIES 2 can be used as a free-standing unit. The rack-mount
ears may then
be replaced by the blanking plates if desired.
To replace the ears with the blanking plates:
• Unscrew the three bolts which attach each ear to the chassis of the
CR-1.
• Attach the blanking plates
IJsing the same retaining bolts. Do not
over-tighten these bolts as doing so may cause damage to the CR-1.
CR- 1 SERIES 2: Rev.02 Ver.3.06 Page - 7
October
10, 1995

Power
Balanced Balanced Connector
Timecode
Analogue Analogue with integral
Input and Output
Inputs Outputs fuse holder
I
-I
LTC VITC
t t t j j
R - IN - L R - OUT - L IN - LTC -OUT IN -VlTC -OUT • CAUTION
• •
POWER
A~O IA~ 0
RISK ;'~~~oc. ~
w@} ~ 00 .. \@~
, 0 0 0 ~~.
o o
o
~A\'~A\ .~.
AES - IN - SPOIF SPDIF - OU~ - AES IN OUT THRU I •
RS 232 INTERFACE
8 0 0 0· @@@
0
•
~
o. • ~
00
~
L---, J
Digital 110
SP-DIF I I
I MIDI
In/OutlThru RS232 Interface
Digital
110
AESIEBU

CONNECTIONS
The CR-1 SERIES 2 may be connected to most of the professional audio
equipment currently available. Three types of audio input and output are provided
(one analogue and two digital) and these will satisfy most users' interconnection
requirements. Full descriptions of these connectors will
be found later in the
manual.
1. BEFORE CONNECTION
• To prevent problems and possible equipment damage, turn off the
power to all equipment before making connections.
•
Be sure to insert plugs firmly into sockets. Loose connections may
cause hum and noise.
• When unplugging any lead, do
so by grasping the plug, not the lead.
2. POWER CONNECTIONS
Ensure that the CR-1 SERIES 2 is switched OFF before inserting the mains
lead.
NOTE: Users with 2-pin mains supplies:
When the CR-1 SERIES 2 is connected to other audio components, the AC
hum of the unit may be increased or decreased by reversing the direction of
the power connector
in the socket. Check that the cord is in the favourable
position ('in-phase') with respect to other audio devices
in the chain. This
will ensure that the best sound quality
is obtained from your CR-1.
For further information
on grounding and polarity consult a person familiar
with studio grounding techniques.
3. SIGNAL LEAD CONNECTIONS
Refer to the Rear Panel diagram:
The
CR-1 SERIES 2 offers three audio connection standards: one analogue
and two digital. These are:
• balanced analogue audio I/O
• digital SP-OIF format audio data
• digital AES/EBU format audio data
Note that the CR-1 SERIES 2 always passes its output to all three signal
outputs irrespective
of the input used, but that the digital data will only be
formatted for either AESIEBU or SP-OIF, as defined
by the userparameters.
CR- 1 SERIES 2: Rev.02 Ver.3.06 Page - 8
October 10. 1995

(i)
Balanced analogue audio 1/0 (Pin 2 -
'hot')
This standard is used in professional audio equipment. Connect the
output from your source
to the balanced analogue inputs of the CR-1
SERIES 2 using standard XLR plugs. You will require two such
connections: one for each channel.
The balanced audio output may be used to connect the
CR-1 SERIES
2 directly to audio equipment such as mixing desks and professional
recorders featuring balanced XLR inputs and outputs.
(ii) Digital SP-DIF format audio data
The SP-DIF format is used by domestic and semi-professional digital
audio devices such
as DAT machines, some ADCs, and some CD
players. Both audio channels are carried along a single cable,
so you
may connect the SP-DIF output from your source to the SP-DIF input
of the
CR-1 SERIES 2 using a single cable terminated with RCA (or
'phono') plugs.
The SP-DIF output of the
CR-1 SERIES 2 may be connected to the
SP-DIF input of your recording device or external DAC.
(iii) Digital AES/EBU format audio data
The digital AES/EBU format is used by professional digital audio
devices including mastering systems, DASH recorders, and high
quality ADCs & DACs. Both channels of audio are carried along a
single cable, so you may connect the AES/EBU output from your
source to the AES/EBU input of the
CR-1 SERIES 2 using a single
cable terminated with XLR plugs.
The AES/EBU output of the
CR-1 SERIES 2 may be connected to the
AES/EBU input
of your digital mixer, recording device or external
DAC.
24-bit Digital data resolution:
The CR-1 SERIES 2 features 24-bit input and output resolution
whenever the AES/EBU digital input and output are utilised.
Dithering:
The CR-1 SERIES 2 also features TPDF (Triangular Probability
Density Function) dithering. This
is applied to the digital data when
the SP-DIF output format is selected. Dithering
is always applied to
the data presented to the DACs.
CR- 1 SERIES 2: Rev.02 Ver.3.06 Page-9
October
10, 1995