Cedar DH-1 De-Hisster Owner'S Manual Download

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Summary of Contents for DH-1 De-Hisster

Page 1: ...Professional Hardware Systems DH 1 De Hisser Digital Audio Restoration System SERIES 2 OWNER S MANUAL 1994 CEDAR Audio Ltd Written by Gordon Reid DH 1 Rev 02 Ver 1 06 Page 1 July 12 1996 ...

Page 2: ...ad Connections 12 Other Connections 14 SAMPLE INSTALLATION IDEAS 15 A GUIDE TO RESTORATION PROCESSING 16 FRONT PANEL INDICATORS AND CONTROLS 18 QUICK TOUR 20 WARMSTART AND COLDSTART 21 OPERATING THE CEDAR DH 1 22 Dedicated ControIs 22 PAGES 24 Control Page 25 Input Output Control Page 28 Remote Con trol 32 Status Page 33 Status Indicators 33 TUTORIAL 35 THE TUTORIAL TAPE 38 REMOTE CONTROL PROTOCOL...

Page 3: ...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 I Delta Sigma technology 103dB dynamic rang...

Page 4: ...m is used inappropriately to describe artefacts such as intermittent electrical clicks or microphone grounding These problems produce clearly identifiable events of limited duration and may be corrected by the CEDAR DC 1 De Clicker and CR 1 De Crackler using quite different methods to those described below On the other hand broadband noise is constantly present to a greater or lesser degree in eve...

Page 5: ... they tend to round off fast transients such as snare drums and samples which have a habit of introducing high frequencies very rapidly into the signal And because their raison d etre is to reduce the signal bandwidth they also tend to dull the genuine signal quite perceptibly So to summarise dynamic filters if you re not compromising the signal you may not be removing as much noise as you wish an...

Page 6: ... expander described above encounters a very quiet signal it further reduces the volume But what if there is still a significant signal at say 3kHz but very little elsewhere in the frequency spectrum The single band expander has no way of knowing that there s an important genuine signal within a limited range and it shuts this out at the same time as all other frequencies What s needed is an expand...

Page 7: ...e true Unfortunately it is The noise spectrum of a recording the spectral fingerprint can only be accurately measured if there is an otherwise silent passage within the music If the fingerprint is wrong maybe because you have captured some lingering reverb or because a compressor has been applied at some time or because the original recording engineer has faded sections in and out of the recording...

Page 8: ...eduction System and the DH 1 The DH 1 includes revolutionary new algorithms which have finally dispensed with this requirement enabling you to remove noise in a powerful yet automated fashion The DH 1 will itself analyse the noise content of a signal whether genuine sound is present or not and apply all the power of CEDAR s latest noise removal algorithms to this signal The results speak for thems...

Page 9: ... place subject to strong sunlight excessive dust mechanical vibration or periodic shocks 6 Wall or Ceiling Mounting The DH 1 has not been designed for mounting directly to walls or ceilings 7 Ventilation Good air circulation is essential to prevent internal heat build up within the DH 1 The DH 1 should be situated so that its position does not interfere with proper ventilation The DH 1 should not ...

Page 10: ...er by the cord itself 13 Cleaning Clean only with a dry cloth NEVER use liquid cleaners such as alcohol or benzene on the DH 1 NEVER use abrasive pads on the DH 1 14 Damage Requiring Service The DH 1 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 t...

Page 11: ...tal 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 DH 1 can be mounted in a standard 19 EIA rack 4 FREE STANDING USE The DH 1 can be used as a free standing unit The rack mount ears may then be replaced by the ...

Page 12: ...N L R OUT L IN LTC OUT IN VITC OUT g o QQI Q AES IN g0 SPDlF SPDIF OUT AES o o J Digital 110 SP DIF Q o o 0 o o IN OO o 0 o OUT THRU oo oo o 0 0 0 o 0 I o 0 RS 232 INTERFACE 000 1 I CAUTION 00 NOT OPEN POWER HO USE SERVICEABLE PARTS INSIOE RISK Of ElECTRIC SHOCK 3 h Lh t j Serial No I MIDI In OutlThru RS232 Interface Digital 1 0 AES EBU ...

Page 13: ...s 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 Cin phase with respect to other audio devices in the chain This will ensure that the best sound quality is obtained from your DH 1 For further information on grounding and polarity consult a pers...

Page 14: ...rofessional 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 DH 1 using a single cable terminated with XLR plugs The AES EBU output of the DH 1 may be connected to the AES EBU input of your digital mixer recording devi...

Page 15: ...nt ii MIDI IN OUTITHRU The operation of the DH 1 may be controlled using the Musical Instrument Digital Interface MIDI Refer to the chapter on Remote Control Protocols for further instructions iii RS232 The DH 1 may be controlled using the standard RS232 serial communications protocol Refer to the chapter on Remote Control Protocols for further instructions DH 1 Rev 02 Ver 1 06 Page 14 July 12 199...

Page 16: ... digilal in dlgiialoul digital in SOURCE RECORDER MIXER elleclsrelUrn line in line oul l AMP DH l 2 OH 1 used on the effects loop within a studio environment analogue or analogue or anabgueor analogue or analogue or line oul digllal in digiial oul digilal in dignaloul digilal in DH l r CEDAR r RECORDER I SOURCE Jt Dr O Ilier rYorKSlalioniedilo linein AMP 3 OH 1 used in line prior to an editor or a...

Page 17: ... CEDAR De Hiss products HISS 1 HISS 2 DH 1 De Hiss they confuse the processes and create unmusical side effects In addition De Hissing at this stage will make it almost impossible to identify and remove clicks and scratches at a later time De Crackling should be the next process because even small crackles can cause the same problems as in ii above Azimuth Correction can be carried out either befo...

Page 18: ...r material Next remove crackle and buzz and reduce distortion if appropriate Then apply Azimuth Correction to material with phase and balance problems Finally apply noise reduction DH 1 Rev 02 Ver 1 06 Page 17 July 12 1996 ...

Page 19: ...Power Signal Signal LCD Status Function Control Switch Meters Meters Screen Indicators Keys Wheel Headphone Level Control CD Headphones Socket CD Input Level Control Output Attenuation Control ttl 1 t Fl F2 F3 F4 F5 I Function Contrast Keys Control ...

Page 20: ...D screen Please refer to the following chapters for full instructions 5 Status Ind icators Indicate the status of the analogue and digital inputs and whether the DH 1 SERIES 2 is in idle or processing modes Also indicate the possible causes should the unit fail to function 6 Dedicated Function Keys Certain functions are fundamental to operating the DH 1 and these are controlled by the Dedicated fu...

Page 21: ... ratio SIN from the ADCs This work must be carried out by qualified service personnel so please refer to your authorised dealer or directly to CEDAR Audio to have this modification performed 11 Output Attenuation Control A digital gain control with range 0 to 1 OdB in 1dB steps 12 Function Keys Use along with the LCD screen Please refer to the following chapters for full instructions 13 Contrast C...

Page 22: ...tputting to a consumer format machine such as a low cost DAT recorder press A function key F1 to select SP DIF format Press PAGE twice to return to the Control Page Note The OH 1 defaults to AESIEBU PROFESSIONAL format so skip both instructions 5 i and 5 ii if your OH 1 is connected to a system such as the Sony PCM1630 6 Play your material through the DH 1 7 Press function key F2 to select the LEV...

Page 23: ... are LEVEL 0 00 ATTEN 40 0 AMB 0 00 Other default values are Digital Output AES EBU Input Source AES EBU Receiver Error Level 1 Lock MIDI Channel 1 Bypass OFF A to 0 frequency 44 1 kHz Pre Post Post Warmstart The DH 1 remembers the latest parameters used and the page that was active at the time that the system was last switched off On start up the DH 1 will display the message Warmstart on the scr...

Page 24: ...of approximately 0 1 mS in any digital to digital signal passed through the DH 1 in Bypass mode All delays are group delays i e are constant at all frequencies and are measured at a sample rate of 44 1kHz Page Use this Function Key to move between Pages Pre Post It will often be useful to compare the original Signal with the post processing output of the DH 1 The current status will be indicated o...

Page 25: ...l We recommend a peak level of approximately ato 3dB as shown on the Input Signal Meters Output Attenuation Avoid clipping using the Output Attenuation Control This is not a compressor or limiter and acts purely as a digital gain control with variable gain from OdB to i0dB in idB steps DH 1 Rev 02 Ver 1 06 Page 23 July 12 1996 ...

Page 26: ...unit was last used All the controls for the DH 1 are contained in the PAGES each of which is selected by pressing the dedicated PAGE function key The Pages are cycled and will appear in the following order Control Page I O Control Page Remote Control Page These and a further description of the Dedicated Controls are now covered in turn Note There is a fourth normally hidden page called the Status ...

Page 27: ...Right Control F2 Level Control F3 Atten Attenuation Control F4 Amb Ambience Control F5 Clear The controls and therefore the DH 1 itself act in the following manner A Oltl once Level AilenLO lion 1 ___ OulplJ Inpul I Figure 1 The 0 1 1 process overview and the stages at which the CONTROL PAGE controls modify the signal You can optimise the beneficial effect of the DH 1 by setting each of these cont...

Page 28: ...ffects or loss of high frequencies caused by over or under processing are heard in the output signal It may be adjusted as follows Press F3 to select the ATTEN control A box will appear around the numerical display to indicate that the control is selected Rotate the a dial clockwise and or anti clockwise to alter ATTEN in steps of 0 1 Rotating the a dial slowly will result in delicate adjustments ...

Page 29: ...ntically unless such adjustment would move a channel beyond the limits of the scale In this mode the numeric readouts beneath the control bars displays the average value of the left and right channels values Left Only the left channel is affected and the numeric readouts beneath the control bars displays the left channel s values Right Only the right channel is affected and the numeric readouts be...

Page 30: ...ions in the 1 0 Control Page A DIGITAL OUTPUT This option defaults to AES EBU To toggle between the two output modes AES EBU and SP OIF press the Function Key marked A on the LCD screen AES EBU FORMAT When AES EBU is selected both the phono and XLR connectors will carry AES EBU specification audio data You should patch the output from the XLR connectors to your recording device The OH 1 features 2...

Page 31: ... lit 32 kHz signal presented to inputs 44 1 kHz LED lit 44 1 kHz signal presented to inputs 48 kHz LED lit 48 kHz signal presented to inputs CLOCK DETECTION If the DH 1 fails to detect a digital signal within the following limits the 44 1 kHz and 48kHz LEOs will flash continually This will be irrespective of any other system settings Acceptable ranges 44 1kHz 48kHz 32kHz 4 4 4 SAMPLE RATE OF A TO ...

Page 32: ...id digital input to either of these and selecting AES Sync or SP OIF Sync as appropriate will lock the OH 1 to the external clock If the external clock falls within the acceptable ranges of each of the standard sample rates 44 1kHz 48kHz 32kHz the clock frequency will be shown on the LEOs If the external clock lies outside these ranges the OH 1 will still function and good audio will be produced a...

Page 33: ... This indicates that the incoming digital audio data is of poor quality i e very noisy or jittery and that undetectable data errors are likely These errors will not be corrected by any standard AES EBU or SP OIF device and may lead to audio degradations 4 Valid This is the most stringent test of the incoming data and will cause the LED to flash if the 0 H 1 determines that any of the data containe...

Page 34: ... control the DH 1 over MIDI MIDI CHANNEL Ensure that button A is highlighted by a box It is then possible to change the MIDI Channel turn the Ct dial clockwise to increase or anti clockwise to decrease the MIDI Channel To toggle this function on off press the Function Key marked A On Coldstart the MIDI Channel defaults to 1 RS232 CEDAR Audio Ltd do not produce software for remote devices to contro...

Page 35: ...garding any errors which have occurred since the unit was switched on Three items of information will always be reported by the DH 1 These are DSP1 Status Crashed Timed Out Running OSP2 Status Crashed Timed Out Running 110 Condition Error Emphasis Sample Rate If a remote control error is detected a fourth field will appear Comms Error Illegal Checkbyte Illegal Command Size STATUS INDICATORS The fr...

Page 36: ...have been doing so since the unit was switched on If the DIG ITAL LED is flashing the most serious error will be detailed at this point Errors are fully detailed in the DH 1 Service Manual If no error is detected the 1 0 status will display the Emphasis condition OFF The Emphasis bit is not set The DAC de emphasis will not be engaged 50 15 The Emphasis bit is set to 50 15 S The DAC de emphasis wil...

Page 37: ... effects and then further reduce the LEVEL by a small amount which ultimately only experience can teach you to judge Note The sensitivity of LEVEL is very high and the setting should be controlled using the very accurate numerical readout not the coarse fader representation WARNING If you are using the analogue inputs you must not adjust the front panel INPUT LEVEL CONTROL after you have found a s...

Page 38: ...educed effect As you reduce ATTEN you may notice one of two detrimental effects occurring If there were twitters present after step 3 and if you reduce ATTEN beyond the optimal level for the specific material being processed the twitters may be re introduced as a form of high frequency noise modulation If there was loss of high frequencies present after step 3 you will notice that this loss is gra...

Page 39: ...uld be grateful to receive feedback from our users regarding their experiences with the DH 1 Any suitable hints and tips will be included in this tutorial in later versions of the manual WARNING Some users may use commercial test CDs or signal generators to test the operation of components within their audio systems The DH 1 will generate distortion if a digital FSD full scale deflection sine wave...

Page 40: ...ers are introduced Consequently you must if possible find a LEVEL between the hiss and the side effects ATTEN and AMB can then be set as before and provided that the LEVEL is not too high there should be minimal loss of either ambience or brightness Note that the introduction of the track will require heavier processing than the rest because the noise is much more noticeable before the louder pass...

Page 41: ... bytes together form a signed integer Command Numbers Command Values OxF7 Clear Errors command Any value OxF8 Select Page command 1 OxF9 Pre Post command OxFA Bypass command 6 7 15 1 Any other value 0 1 1 Any other value 0 1 2 3 1 Any other value OxCO Digital Output Format Ox80 OxOO 1 Any other value DH 1 Rev 02 Ver 1 06 July 12 1996 Clear all error messages Control Page I O Control Page Status Pa...

Page 42: ...ny value Ox33 Alter Right ATTEN Any value Ox24 Set Left AMB Any value Ox34 Alter Left AMB Any value Ox25 Set Right AMB Any value Ox35 Alter Right AMB Any value DH 1 Rev 02 Ver 1 06 July 12 1996 Analogue SP DIF AES EBU Toggle Refresh 44 1 kHz 48kHz SP DIF Sync AES EBU Sync Toggle Refresh 1 Lock 2 Code 3 Trans 4 Valid Toggle Refresh Left LEVEL x 100 t Left LEVEL x 100 Right LEVEL x 100 t Right LEVEL...

Page 43: ...used as the basis for an automation system Note The absolute parameter values are not transmitted or received so the user must ensure that any changes are relative to a desired starting value which can be set using MIDI DUMP If a MIDI DUMP of all control page parameters and the Pre Post state is required pressing ENTER at any time will initiate the DUMP Additional MIDI Command The DH 1 will receiv...

Page 44: ...ou to press each of the Function Keys except ENTER and each of the Dedicated Function Keys Pressing a key will cause the display to change from OFF to ON ROUTINE 2 ATTENUATION KNOB TEST The DH 1 SERIES 2 will invite you to turn the Attenuation knob to check that the value displayed on screen matches the position of the knob ROUTINE 3 ex dial S PI WHEEL TEST Rotate the a dial to check that values c...

Page 45: ...ase repeat the self test If the message recurs please contact your dealer for assistance WARNING The DH 1 SERIES 2 contains no user serviceable parts 00 NOT UNDER ANY CIRCUMSTANCES attempt to service your unit ROUTINE 7 DSP2 TEST As above TEST COMPETED Your DH 1 SERIES 2 will now prompt you to press ENTER one more time to return you to operating mode whether all tests have been passed or not Some ...

Page 46: ...Function Keys 18 19 22 24 Gunging 25 27 glugging 35 Grounding 10 Head phone 18 HeJ t 9 HISS 1 16 HISS 216 humidity 1 1 hysteresis 5 I O 22 28 I O Control Puge 24 input 12 18 28 29 Input Level 19 22 23 Input Source 21 J1734 LCD Screen 18 LEVEL 20 21 25 26 35 36 limitt r23 LOCAL OFF 41 LOCAL ON 41 Lock 31 lock out 22 LTC 14 InZlgnetic fields 11 Memory 43 meters 42 1 111013 14 21 32 4 1 MIDI Chi1l1ne...

Page 47: ...Designed and Manufactured by CEDAR Audio Ltd 5 Glisson Road Cambridge CB12HA Tel Fax 44 0 223464117 DH 1 Rev 02 Ver 1 06 Page 45 July 12 1996 ...

Page 48: ...HE AFOREMENTIONED EQUIPMENT FULLY CONFORMS TO THE PROTECTION REQUIREMENTS OF THE FOLLOWING EC COUNCIL DIRECTIVES ON THE APPROXIMATION OF THE LAWS OF THE MEMBER STATES RELATING TO 89J3361EEC ELECTROMAGNETIC COMPATIBILITY APPLICABLE STANDARDS EN 50081 1 92 EN 50082 1 92 73 23 EEC LOW VOLTAGE EQUIPMENT APPLICABLE STANDARD BSEN 60 065 1994 SIGNED GORDON REID POSITION MANAGING DIRECTOR DATE 19 DECEMBER...

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