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Model CP500 Digital Cinema Sound Processor Users' Manual Issue 2 Part. No.
Users' Manual For Model CP500 Digital Cinema Sound Processor Dolby Laboratories Incorporated U.S.A. 100 Potrero Avenue, San Francisco, CA 94103 Tel: 415-558-0200; Fax: 415-863-1373; www.dolby.com U.K.
TABLE OF CONTENTS SECTION 1 INTRODUCTION 1.1 About the Dolby CP500 ....................................................................... 1-1 1.2 About This Manual............................................................................... 1-1 SECTION 2 OPERATING INSTRUCTIONS 2.1 The CP500 Front Panel ........................................................................ 2-1 2.1.1 Soft Keys: SK1 to SK8......................................................... 2-1 2.1.2 Hard Keys.......................
ii SECTION 4 TROUBLESHOOTING 4.1 During the Show................................................................................... 4-1 4.1.1 If Film Sound Is Lost:............................................................ 4-1 4.1.2 If One Channel Fails or is Distorted...................................... 4-3 4.1.3 If Switching to Bypass Does Not Restore Sound .................. 4-3 4.1.4 If You Hear Extraneous Noises When Playing a Digital Film ..........................................................
SECTION 1 INTRODUCTION 1.1 About the Dolby CP500 Dolby Laboratories has continuously established new benchmarks for motion picture sound. The CP500 Digital Cinema Processor maintains that tradition, setting new standards for performance, value, flexibility, and convenience. Once installed, the Dolby CP500 Cinema Processor becomes the heart of your theater sound system. All sound sources are connected to the CP500, which processes the signals appropriately and feeds them to the power amplifiers.
1-2 For the sake of clarity, boldface type is used for all specific references to the CP500 controls and their labels, such as Mute, and front-panel Main Fader. In addition, indicator lights on the CP500 are referred to in the text as LEDs (light-emitting diodes). WARNING The CP500 was adjusted initially by a specially-trained engineer so that your theater would have the same standard playback characteristics as the dubbing theaters in which all Dolby films are mixed.
SECTION 2 OPERATING INSTRUCTIONS 2.1 The CP500 Front Panel 2.1.1 Soft Keys: SK1 to SK8 (SK1) (SK5) (SK2) (SK6) (SK3) (SK7) (SK4) (SK8) The buttons located on each side of the LCD display are called "soft keys" (SK). They do not have a single fixed function. Their function is software controlled and can change based on the current screen displayed. The purpose of each key is shown on the display screen. 2.1.
BYPASS INDICATOR Indicates continuous red when unit is in bypass mode. SOFT KEYS 1 - 8 Used to select the function shown next to the switch in the front panel display. MUTE ON INDICATOR Flashes when mute is activated. MAIN FADER/MULTI-FUNCTION CONTROL Controls sound level and also is used for data selection in menu operations. (SK1) (SK5) (SK2) (SK6) (SK7) (SK4) (SK8) Displays fader setting. Ranges from 0 to 10. Normally set to 7.0 This display shows '- -' when in data entry mode.
2-3 CANCEL Many of the screens used during set-up or diagnostics contain a "Pop-Up" screen within the main screen. The CANCEL key is used to cancel the current pop-up operation being performed and restore any data that was changed during the pop-up screen operation to its original value. OK This key is used to accept and store the current setting in a pop-up screen. EXIT This key is used to signal completion of an adjustment procedure or select the previous screen.
2-4 2.2 System Password Many of the CP500 alignment functions are normally protected from unauthorized access by using a system password. A password is stored by the installation technician after the system is aligned in order to block any changes to the B-chain alignment, calibrated level settings, or time delays. Knowledge of this password is required to enter these special CP500 menus. 2.3 Normal Operation 2.3.
2-5 2.3.2 Format Selection Select the desired film soundtrack format or your non-sync source by pressing the appropriate softkey. The LED next to the key illuminates, the text next to the softkey is reversed (dark), and the format number appears under Current Format to confirm that the format was selected. Common formats are as follows: x 01 Mono: for all optical prints of any vintage with conventional mono optical (“Academy”) soundtracks.
2-6 Format 10 is the format that the auto-digital system will switch to when good Dolby Digital data is detected. It is marked with an “a” (for automatic) on the screen. Format 10 is defined as the “target” format, in this case. To enable the auto-digital feature: Press Menu. MENU SK7 Then, press SK7. Pressing SK7 alternately enables and disables the auto-digital feature. To disable the auto-digital feature: You may disable auto-digital operation by pressing the MENU key and SK7.
2-7 Operation with Custom Format Screen and Special Configurations If the installation engineer has configured your CP500 to be different from the standard screen, the same operating methods apply. Formats designated with an “s” are source formats for the auto-digital feature, and the format(s) designated with an “a” is the target format(s). Disabling and enabling the feature works in the same way as described above. 2.3.
2-8 2.3.5 Mute Function The MUTE key is useful if the film breaks or runs out, while the projector is active, since it suppresses the very loud signal that occurs when leaders or tails pass through the sound gate. When you press the MUTE key, the volume will automatically fade all the way down on all channels. A green LED, MUTE ON, located above the fader level display will flash, indicating that the CP500 outputs are muted.
2-9 The following occurs when the CP500 is in the bypass mode: x Only the front panel main fader operates, no other remote fader will work. x All other commands from the front panel keys are ignored by the unit. x The optical preamp output of the selected projector remains operational and is fed to the CP500 output card. x Even when a stereo print is playing, a mono signal is fed to all the screen speakers.
2-10 2.4.1 Manual Bypass Selection The CP500 can be manually switched to bypass using either of two methods: 1. Open the front panel and operate the pushbutton switch located on the right-hand side of the unit. Use this method in an emergency situation, or POWER / BYPASS 2. Perform the following steps: Press the MENU key. MENU SK1 Press System Setup (SK1). Press Bypass (SK8). A pop-up box appears, warning that the CP500 is now set to bypass operation.
2-11 2.5 Customizing Features 2.5.1 Setting the LCD Display Contrast The Contrast level of the front panel LCD display can be adjusted by following these menu steps: press: screen shows: Menu Format Selection key press: screen shows: System Setup Menu Selection Begin the procedure by pressing the MENU key, Press System Setup (SK1), key Press CP500 Controls (SK1). press: screen shows: CP500 Controls System Setup FORMATS key Menu Cancel OK Exit Press LCD Contrast (SK1).
2-12 2.5.2 Setting Mute Speed The length of time it takes for the sound to fade from normal setting to muted (when the MUTE key is pressed) is adjustable. To make this adjustment, press: screen shows: Menu Format Selection Press the MENU key, key press: screen shows: System Setup Menu Selection key System Setup (SK1), press: screen shows: CP500 Controls System Setup key CP500 Controls (SK1), Mute Speed Adjustment (SK7).
2-13 2.5.3 Customizing the Format Display Screen There are two types of Format Selection display screens. The unit is shipped in Standard Mode, which allows selection of eight commonly used formats. There also exists a Custom Mode which allows the user to program the softkeys to show formats of his own choosing, along with changes to the fader setting and projector selection for each of these softkeys.
2-14 FORMATS To assign formats to the softkeys press the Assign Formats key (SK1). FORMATS Menu Cancel OK Exit A copy of the existing format selection screen is displayed. Pressing any softkey causes a pop-up box to appear, allowing any format to be assigned to that softkey. This example shows the display after SK4 has been pressed for assignment. Rotating the front panel knob will move the display through the formats available. When the desired format is shown, select it by pressing the OK key.
2-15 FADER SETTINGS Assigning fader settings to the softkeys is done in a similar fashion. FORMATS Menu Cancel OK To assign fader settings, press Assign Fader Settings (SK2). Exit Once again a copy of the format selection screen is displayed. Pressing any softkey causes a pop-up box to appear allowing a fader setting to be entered for that softkey. This example shows the display after SK4 has been pressed to set a fader value for SK4, Format 10, Dolby Digital.
2-16 ASSIGNING A PROJECTOR FORMATS Menu Cancel OK Assigning or "linking" a projector selection to the softkeys is done in a similar fashion. To assign projector selection, choose Assign Projectors (SK5). Exit Once again a copy of the format selection screen is displayed. Pressing any softkey causes a pop-up box to appear allowing a projector selection to be entered for that softkey. This example shows the display after SK4 has been pressed to link a projector to SK4, Format 10, Dolby Digital.
2-17 Press the FORMATS key to return to the format selection screen. FORMATS Notice that a small indicator (CUST) now appears next to the Current Format area, indicating that 'Custom' screen mode is active. Any fader settings and projector selections are also displayed. In this example, the screen tells you that the fader setting has been adjusted to 6.5 and Projector 1 has been selected.
SECTION 3 MAINTENANCE AND ADJUSTMENTS The installation of the Dolby CP500 in your theater indicates a commitment to providing a high-quality presentation to your audiences. However, the presence of even the very best equipment does not in itself guarantee the best results. A number of routine maintenance and adjustment procedures, requiring no special test equipment or technical knowledge, are necessary to realize the full potential of the sound system on a day-to-day basis.
3-2 3.1.2 Dolby Level Adjustment Proper decoding of Dolby encoded soundtracks requires careful level matching between each channel of each soundhead and the CP500 (see Appendix C for a discussion of why Dolby Level is important). When the CP500 is first installed, the installer makes this adjustment for you. We recommend that you routinely check Dolby Level, but only adjust it to compensate for the normal aging of the exciter lamp.
3-3 press: screen shows: Begin the Dolby Level adjustment by pressing the following: Menu Format Selection key press: screen shows: Menu Selection MENU key Diagnostics key press: screen shows: Diagnostics (SK3) Set Dolby Level key Diagnostics Set Dolby Level (SK2) Auto Level (SK7) FORMATS Menu Cancel OK Exit A pop-up screen appears which allows you to select Projector 1 or 2 as the Dolby Tone input source.
3-4 3.1.3 Digital Sound System The Digital Soundhead should be kept clean and free of dust and dirt for best performance, just like the analog soundhead. Wiping the external surfaces with a clean cloth on a regular basis will keep the head looking new. The optical path should be inspected regularly and kept clean with a photographer’s lens cleaning kit (available from most camera stores). Use care not to scratch the lens.
3-5 3.2 Print Cleanliness A high fidelity Dolby-equipped theater system is like a high-quality home stereo system: it can sound only as good as the program material played through it. Just as a good home stereo clearly reproduces the annoying pops and clicks on poorlyreceived radio signals, a good theater system reproduces pops, crackles, and other noises from worn and dirty film prints.
SECTION 4 TROUBLESHOOTING Your theater sound system consists of a number of critical audio components in addition to the Dolby CP500. Thus, the first step when something goes wrong with the sound is to find the source of the problem. The troubleshooting chart, starting on page 4-7, can be helpful. If the troubleshooting chart is not sufficient for finding and solving the problem right away, the procedures in the following manual sections should be helpful.
4-2 4.1.2 If One Channel Fails or is Distorted 1. Open the front door of the CP500 and switch to Bypass using the pushbutton switch in the lower right corner. A mono signal is then fed to all three screen channels. If the problem in one channel persists, the power amplifier or speaker for that channel is probably at fault. If the problem is not in the Center channel, switch the faulty amplifier off, being sure that it is not shared with the Center channel, and finish the show in that condition.
4-3 4.1.5 Excessive or Inappropriate Sound From Surround Speakers 1. As an emergency measure to continue the show, switch off the surround channel power amplifier(s). At your next opportunity, find out if the problem is related to the film itself or the theater sound system. The problem is most likely to be in: x x x x x 4.1.6 Power amplifier gain settings; Damaged loudspeakers rattling, etc.; Solar cell alignment in the projector (if the problem is analog sound); Cat. No.
4-4 Next, turn off the power amplifiers so as not to disturb the audience. The CP500 is equipped with several sets of LEDs which indicate the presence of signals. These LEDs can assist in fault diagnosis. If you have only a small amount of time between shows, then you may wish to perform this procedure after the theater has closed. NOTE: The signals do not flow straight across the unit from left to right. 4.2.
4-5 Next in the signal path for all formats are the LEDs on the Cat. No. 675A card that are located seven slots from the right hand side of the unit (J14). The top six LEDs indicate that signals are present in the respective channels. This card functions as the equalizer card. The Cat. No. 675A, as discussed previously, shows lights, but if this card does not, then one of the two Cat. No. 675A cards is defective. The last point in the signal processing chain for all formats is the Cat. No.
4-6 The next LEDs in the digital sound path are on the Cat. No. 675A AC-3 Decoder card, located two slots from the right hand side of the unit (J19). This card has three columns of eight LEDs. The top four LEDs in each column indicate signals present in the L, Ls, and C channels respectively. The bottom four LEDs in each row indicate signals present in the R, Rs, and SW channels.
4-7 Symptom Probable Cause Recommended Action NO SOUND AT ALL No sound, front panel dark, no bypass LED No power to either main or bypass systems. See if mains panel fuse or circuit breaker feeding the CP500 is blown. Verify all power connectors are fully inserted into their sockets. If power is present, see if CP500 bypass transformer is installed correctly. Verify that Cat. No. 682 card is fully seated in its connector. No sound, and switching to Bypass doesn’t restore sound.
4-8 Symptom Probable Cause Recommended Action The analog exciter lamp or power supply may have failed or the wrong projector may be selected. Solar cell connections may be loose or damaged. The Cat. No. 661 optical preamp may have failed. Digital exciter lamp/LED not working, If signal present LEDs on the Cat. No. 661 (J3) are not flashing, verify exciter operation and solar cell connections as described above. Substitute known good Cat. No. 661.
4-9 Symptom Probable Cause Recommended Action Fader level display indicates “AU” and front panel fader has no effect Auditorium analog fader selected. Select front panel fader. Fader level display changes when no change in CP500 front panel fader has been made Remote fader is being operated; If in Custom screen, new format with different fader setting selected In the screen menu structure, go to MENU/System Setup/CP500 Controls and disable the auditorium fader.
4-10 Symptom Probable Cause Recommended Action RUMBLES, WHISTLES, HUM etc. IN SOUND Rumble in sound, regardless of format Whistles in sound Hum (power line frequency) in sound Audio grounding scheme may need changing. Audio grounding scheme may need changing. Malfunctioning exciter lamp or lamp power supply. Call service engineer. Call service engineer. Cover the solar cells with a business card or other opaque object.
4-11 Symptom Probable Cause Recommended Action TROUBLE IN ONE OR MORE CHANNELS One channel fails. Defective power amplifier, external crossover, or wiring for that channel. Place the CP500 in bypass. All three screen speakers should become active. If not, there is a fault in the power amplifier, external crossover, or wiring for the missing channel. Check if the amplifier concerned is on and check for blown fuses.
4-12 Symptom The sound from two or more channels is distorted (you can detect the distortion at the booth monitor at normal listening level). Probable Cause Malfunctioning 2-channel power amplifier. Recommended Action If two distorted channels are served by the same 2-channel amplifier, the problem may be in the amplifier. See the manufacturer's instructions. Call service engineer. When a stereo film is projected, the sound appears to be coming from the wrong speakers.
4-13 Symptom There is distortion when you play nonsync sound, but sound from the film is not distorted. Probable Cause The non-sync source is introducing distortion. Recommended Action Change the non-sync selection in case the track being played is distorted. If you have control of the output level of the device (cassette deck, CD player, etc.), it will be useful to turn down its volume especially if you have to operate the non-sync with the fader a long way below 7.
4-14 Symptom Probable Cause Recommended Action CHANGEOVER AND CONTROL TROUBLES Projector changeover command does not change to sound output of the selected projector and the front panel LEDs do not light according to the projector selected. Defective changeover relay or switch. If possible, check that the relay or switch contacts actually open and close as the changeover command is issued several times. Defective wiring from relay or switch to terminals on rear of the CP500.
4-15 You can hear pops and thumps during projector changeover. If your projector changeover relay power is DC, a diode should be soldered across the winding of the relay to prevent noise from the relay winding from leaking into the audio wiring. This diode may be missing or defective. If possible, check that the diode is installed across the relay winding. If you are familiar with such electronic components, check to see that it is not blown.
a APPENDIX A HOW TO IDENTIFY SOUND TRACKS ON PRINTS A Dolby Digital film print or a stereo optical print (A-Type or SR), or a mono optical print should be identified as such on both the film can and leader. However, with handling, the identification may be lost. If you are not sure if you have a stereo analog print, play a reel and find a section with music and/or effects only (on dialogue or narration, stereo soundtracks look much the same as mono soundtracks).
APPENDIX B DOLBY TEST AND DEMONSTRATION FILMS Several test and demonstration films produced by Dolby Laboratories are available from your equipment supplier. For proper system maintenance, the Cat. No. 69T test film is required and the Cat. No. 251 Jiffy Test Film is strongly recommended. The Cat. No. 69T test film should be formed into endless loops for ease of use. Other test films (Cat. Nos. 69P, 97, 151, 566) are for use only by a trained engineer with special test equipment.
B-2 This is where the Dolby Level Tone on the Cat. No. 69T test film comes into play. The tone on this film is very carefully recorded at the standard reference Dolby Level. When you perform the Dolby Level calibration on the CP500 as this film plays, you are making sure that the tone on the film is converted to a standard reference voltage at the inputs to the decoders. Thereafter, signals from Dolby soundtracks will be converted to the correct voltages for mirror-image decoding.
B-3 Tests provided on the Cat. No. 251 include: Level Set, Channel Identification, Channel Level and Loudspeaker Equalization, Loudspeaker and Amplifier Condition, Projector Wow and Flutter, Overall System Performance, Visual “Quick-checks,” and a Noise and Interference Test. Duration: Picture format: Sound format: B.3 8 minutes 35mm color, can be screened either 1.85:1 wide-screen or 2.35:1 anamorphic Dolby Digital, and Dolby SR Cat. No. 69P, Cat. No. 97, Cat. No. 151, and Cat. No.
APPENDIX C THE EVOLUTION OF DOLBY FILM SOUND Thanks to such developments as multichannel sound, the motion picture viewing experience today is more exciting and involving than ever before. And what the audience hears today is very much the result of a continuing effort to improve film sound originally undertaken by Dolby Laboratories more than twenty years ago. Indeed, the evolution of motion picture sound over the past two decades is, in great part, that of Dolby film sound technologies. C.
C-2 to the older speakers. The result was to ignore the improved high-frequency response of the newer, better units. To forestall compatibility problems, in the late 1930s a de facto standardization set in, the theater playback response that today is called the “Academy” characteristic. Theater owners knew what to expect from the films, and therefore what equipment to install. Directors and sound recordists knew what to expect from theater sound systems, and thus what kind of soundtracks to prepare.
C-3 By the 1970s, however, the film industry declined overall, with fewer films and fewer theaters. The expense of magnetic release prints, their comparatively short life compared to optical prints, and the high cost of maintaining magnetic theater equipment led to a massive reduction in the number of magnetic releases and theaters capable of playing them. Magnetic sound came to be reserved for a only handful of first-run engagements of “big” releases each year.
C-4 Much of the new technology, including noise reduction and equalization, also is applied to 70 mm magnetic releases (also originally designated as Dolby Stereo). Although 70 mm release prints continue to be very expensive, Dolby improvements brought a resurgence of interest in this “big” format for road shows where the ultimate in picture and sound presentation is particularly likely to be reflected in box office figures. There are six magnetic tracks on 70 mm film, two of which carry low bass effects.
C-5 projectors and a digital decoder which interfaces with the theater’s existing Dolby cinema sound processor. C.6 About Dolby AC-3 Conventional digital audio is coded by a technique called pulse code modulation (PCM). As good as it sounds, however, PCM-coded audio coded takes up so much more space than analog audio that it was necessary to invent an entirely new medium, the Compact Disc, to bring digital sound into the home.
C-6 mean more than just special or dramatic effects. The objective is high quality sound reproduction overall—dialogue and music, as well as effects. Dolby technology is a means, not an end. It can be likened to an artist’s palette that provides the director with a full range of colors, where before there were but a few. Above all, Dolby formats have been developed to enhance that very special experience of going to the movies.
APPENDIX D FOLD-OUT DRAWINGS The following pages contain system drawings which may be useful to you. Software Menu Tree Circuit Card Locations and Signal Flow Information NOTE: Cat.No.222 SR/A modules are primarily intended for playback of 35mm photographic sound-tracks, and have headroom capabilities based on that medium. As a result, use of Cat.No.222SR-A modules is not recommended for playback of 35 mm magnetic print-masters or SR encoded 70mm magnetic film.
