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SDDS Print Master
User Manual
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Sony SDDS Print Master User Manual

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SDDS Print Master Guidelines
R evision 2, October 2001
1 SDDS Print Master Format
SDDS Print Master Guidelines, Page 2 of 26
Contents
1 SDDS Print Master Format 4
2 Not es, Hints and T ips 7
3 DAS H Machines – Care and Use 10
4 DT R S Machines – Care and Use 11
1 SDDS Print Master Format
SDDS Print Master Guidelines, Page 3 of 26
5 Akai DD8 machines – Care and Use 14
6 SDDS - T he i ndust r y's best sounding for mat 17
Hear the Difference
17
6.2 System Basics
17
SDDS Products
17
6.4 Big Sound for the Big Screen
17
7 Dolby level versus operating level. Historical notes. 20
8 Subwoof er s 21
9 Glossary of Terms 25
1 SDDS Print Master Format
SDDS Print Master Guidelines, Page 4 of 26
1 SDDS Print Master Format
1.1 Medi a
T he following ar e exampl es of the types of media s ui t abl e for delivering an S DDS Printmaster. However, facilities vary from s ite t o s i te as do cus tomer s’ pr eferred delivery requirements, it is therefore advi s ed that you check with both the cus t omer and t he negati ve r ecor der site whi ch format is required.
For negatives made in: -
Use:-
USA DT RS Hi8
DASH 6 track magnetic f ilm Akai DD8plus MO
UK DT RS Hi8
Akai DD8plus MO
T he r es t of Europe DT RS Hi8 or as specified l ocally
1.2 T rack assignments
Audio Channel DAS H Channel DT R S/ MO Channel
LEFT 1 1 LEFT CENTRE 2 2 CENTRE 3 3 RI GHT CENTRE 4 4 RI GHT 5 5 SUBWOOF E R 6 6 LEFT SURROUND 7 7 RI GHT SURROUND 8 8
LEFT TOTAL (Dolby SR) 11 N/A RI GHT TOTAL (Dolby SR) 12 N/A
OPT IONAL MATERIAL 15 N/A MONO DI AL OGUE GUIDE 16 N/A
M&E LEFT 17 N/A M&E LEFT CENTRE 18 N/A M&E CENT RE 19 N/A M&E RIGHT CENTRE 20 N/A M&E RIGHT 21 N/A M&E SUBWOOF E R 22 N/A M&E LEFT SURROUND 23 N/A M&E RIGHT SURROUND 24 N/A
1 SDDS Print Master Format
SDDS Print Master Guidelines, Page 5 of 26
1.3 Synchr onisati on
Sampling fr equency 44.1kHz. i.e. 44100 samples for every 24 frames of picture.
48kHz can be us ed, but this will be s ample- r ate- conver t ed i n the camer a. Make s ure the box is CLEARLY marked i f the mast er is at 48kHz.
T imecode 25 frames per second, referenced to 50Hz, film speed 24 fps Or 30 frames per second, non drop fr ame, referenced t o 60Hz, film speed 24fps NOT E : For NTSC r ef er en ced mi x ing, the mas ter tape mus t be pr e- s tr i ped at 30fps/60Hz, then “pulled down” on the mix ing s tage to 29.97fps NTSC s yn c wi t h
44.056kHz sampling frequency. I n this case t he film speed i s 23.98 fps. T imecode mus t be r ef er enced to the di gi tal audio. Reel 1 = 1 hour start, reel 2 = 2 hour etc.
Head pop/ s ync p i p should s t ar t two seconds or 3 feet before the f i r s t frame of picture. e.g. for reel 1, pip at 1:00:06:00, first frame at 1:00:08:00.
1.4 Audio and l evels
Operating level is –20dBfs. Wide band pink noise at the s ame RMS value as this will
produce t he following SPL s in the ci nema. Please note, to compar e level s of tone and pink noise, a t r ue R MS voltmeter must be us ed. Console meter s will read di fferently for tone and pink noise.
Channel SPL C-Weighted meas ur ement
LEFT 85 LEFT CENTRE 85 CENTRE 85 RI GHT CENTRE 85 RI GHT 85 SUBWOOF E R Appr ox 91 see* LEFT SURROUND 82 RI GHT SURROUND 82
*T he s ubwoofer channel has 10dB of in band gain. For a f ull explanation of this, see the “S ubwoofers ” section on page 21. T ones should be r ecor ded on all used channels at the head of each reel . 30 seconds each of 1kHz at –20dBfs, and pink noise at the RMS level of the 1kH z tone.
Surround del ay is set in the cinema pr ocessor. No del ay on the mas ter .
Overlap. 2 seconds or 3 feet of audio fr om the s ubs equent reel must be r ecor ded
after the end of the reel . This can optionally end wi th a t ail pip.
A/D conversion. No audio pr e-emphas i s .
1 SDDS Print Master Format
SDDS Print Master Guidelines, Page 6 of 26
1.5 Medi a l abelling
T he tape or disc s houl d be l abelled wit h:
§
T he name of the film
§
T he r eel number
§
T he wor ds “SDDS master”
§
T he l anguage ver s i on
§
T he date
T he box should be labelled wit h the above things and al s o:
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T he s ampling f r equency
§
T he ti mecode fr ame r ate
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T he film s peed
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T he tr ack assignment
§
Details of tones
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T imecode s tar t time
§
T otal footage
1.6 Checking
It is strongly recommended t hat all SDDS masters are pl ayed back with picture after recording, before t he opti cal transfer is made. A di git al clone could be als o made at this time.
1.7 T est tapes
T est tapes are available fr om the Sony Cinema Pr oduct s (SCP) office, details on page Error! Bookmark not defined.. These contain 1kHz at –20dBfs plus pink noise at the RMS value of this tone.
2 Notes, Hints and T i ps
SDDS Print Master Guidelines, Page 7 of 26
2 Notes, Hints and Tips
2.1 Setting up t he st u di o
T he dubbing theat r e monit or i ng s ys tem shoul d be equalised to the i ndus tr y standard ISO-2969 “X” curve, as used in cinemas. The method us ed to achi eve this is beyond the scope of this text, but details can be found in the DF P- 3000 Quick Start Guide, available fr om S ony Cinema Pr oduct s (SCP) office, details on page Error! Bookmark not defined.. This is usually carried out before t he pr oj ect is begun.
It is important to r ecord the mas ter at the correct level. The audio i s transferred digitally into the camer a, with no oppor tunit y for level adjustments. A r ef er ence “tes t tape” is available f r om the SCP office. Correct studio alignment can be achi eved by following thes e s teps :
§
Play back the 1kHz section of the S DDS test tape. This is recorded at exactly
-20dBfs.
§
T his should r ead house operati ng level at the cons ol e. This is usually 0VU in the USA and 0dB u in the U K . It is also known as “Dolby Level”.
§
Play back the pink noise s ecti on of the t es t tape. Monitor each loudspeaker in turn and s et the moni t or i ng l evels using a S P L meter to t he values shown in section 1.4 on page 5.
§
Send 1kH z at house oper ati ng l evel to the mast er machine. This should r ead
-20dBfs on the r ecor d machi ne met er s . It should al s o r ead oper ating level (unity gain) through the machine at the cons ol e.
If no test tape i s available:
§
Send 1kH z at house oper ati ng l evel to the mast er machine, make s ur e i t reads –20dBfs at the machi ne meter s .
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Check for unity gain through the machi ne, back at the cons ole.
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Measure t he out put of this machine with a t r u e R MS voltmeter, and t hen s end pink noise at the s ame l evel . For 0VU operating level this is 1.23 Vrms.
§
Use t his pink noise to s et the monitor i ng levels as in section 1.4.
2.2 Str iping and syncing
DASH and DT R S tapes should be for matted and pr e- s t r i ped wit h timecode before t he session. I t is imperative that the timecode and digi t al audio ar e l ocked together . T he simplest way to achi eve t hi s is to s tr i pe the tape fr om the machi ne’s internal generator. The optical transfer rooms are s et up wi th a 25fps PAL or a 30fps B&W NTSC v i deo s ync. T imecode i s only used for positional information. The s peed s ync comes from the digi tal audio i ts el f, which is locked t o video, and tr ans f erred di gi t ally to the camer a.
T he r ecommended s et up for studios is to us e a mas t er video s ync, to whi ch everything i s locked; projector, playback and mast er machines. This will give t he bes t results. However some old pr oj ector s run from the mai ns only, without provision for video s ync. I n this case, timecode mus t be gener ated fr om the mai ns - lock ed pr oj ector . T his is usually OK, but it is particularly important to ensur e t he timecode to digital lock is correct. Here we will have a s i t uat i on wher e ti mecode is used for speed i nf or mation
2 Notes, Hints and T i ps
SDDS Print Master Guidelines, Page 8 of 26
in the dubbi ng theat r e and di gital audio i s used when the negative i s made. Extra car e must be t aken.
If NT S C vi deo sync is used i n the dubbi ng theatr e, it is very important that the master tapes are pr e- s tr i ped wi t h 30 non-drop f r ame ti mecode at 60Hz. T his will then mean that the timecode tr ack, control track and A/D conver ter are all running at the same s peed, second for second. 30 frames of code f or 44100 samples and 24 frames of picture. During r ecordi ng of the mast er , the machine mus t be “pulled down” us ing the Fs shift function. This has the effect of locking the A/D converter with the NT S C
29.97 fps video input. T his means that the machi ne tr ans por t , the ti mecode and t he A/D converter will all run slow. 29.97 fps and 44.056kHz. T he pr oj ector in this case will be r unning at 23.96 fps. Therefore 24 frames of picture will still equal 44100 samples.
NE VER stripe at 29.97 NDF. T he “s econds ” of the NDF code will be of longer duration than the “s econds ” of the contr ol track. Therefore 44100 samples of audio will not equal 30 frames of code and 24 frames of picture.
Obviously, if a 48kHz master is required, then similar rules appl y , but the r ecor di ng sampling fr equency would be 47.952kHz in this case.
2.3 Multi-format print masters
T he S DDS format has been car efully designed to enabl e it to fi t in well with other digital audio pr int master sessions, as the moni tor i ng s tandards are compati bl e. T he RMS pink noise at -20dBfs specification is the s ame as DT S and SR D, however some small differences may be found wi th SRD due to his tor ical RMS measurement techniques. T his is currently being addr essed by Dolby and s hor t l y all formats will be within 0.5dB. T o s ave time at the session, the S DDS master can be taken as a par allel feed and all masters can be recor ded at the s ame t ime. However it is very important that the SDDS master is then played back with picture to check for errors.
2.4 Foreign language pr i nt masters
Normally the pr ocedur e i s to r ecor d the mas ter along wi th all other formats as above, then, if time i s short, to us e the S DDS master to make the L tRt . This fold-down process is not ideal for monitoring the mas ter , but allows the S DDS master to be checked t o s ome ex tent. Ideally a s epar at e playback pass should be made (clones can be made at this time, perhaps).
2 Notes, Hints and T i ps
SDDS Print Master Guidelines, Page 9 of 26
2.5 T he i mpor t ance of checking S DDS masters
Digital machines are us ually reliable i n use. However they are s t ill prone to errors such as:
§
Head errors – age or dirt
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Alignment problems
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Losing s ync
§
Slippi n g sync on playback
§
Faulty patch leads
§
T ape dr op out s
§
Weird noi s es from faul ty converters or aliasing
It is therefore vi tal to listen back to all masters with picture. This will avoid cos tl y reshooti ng of negatives. The mast er may not be moni tor ed when it is transferred to film as all soundtracks are s hot in one pass.
3 DASH Machines – Care and U s e
SDDS Print Master Guidelines, Page 10 of 26
3 DASH Machines – Care and Use
3.1 Models
T here ar e fi ve model s in current use
§
Sony PCM3324
§
Sony PCM3324A
§
Sony PCM3324S
§
Sony PCM3348
§
Sony PCM3348HR
T he top t wo machines from thi s list can be us ed but are not recommended. T he others have eas y provision for Fs shift pull down and have a us ef ul 0.2dB per segment calibration mode.
3.2 Head cleaning
Ensure t he utmos t care when cleaning heads on thes e machines . Move i n a s i de to side dir ecti on only. Moving up and down can damage the head per manent l y and replacement is extremely costly. Clean with isopr opyl alcohol and an appr oved chamois cleaning st ick.
3.3 Pre-st r iping
Although you can manage wi th advance r ecor d mode, it is far better to pr e-s tr i pe all tapes. Format at single s peed us i ng advance r ecor d wi th all tracks armed. SCPC do es not recommend us ing the “Pr eS tr i ping” function, which formats at 4X speed.
3.4 Number of reels on a t ape
It is best to have one tape per reel , as this makes replacing r eel s much easier . However tape cos t s are high. If more than one r eel per tape is recorded, then it is recommended that continuous timecode i s recorded t hr oughout the tape. Synchronisation errors will then be mini mis ed. T he box must be clearl y labelled wi th start and end ti mes . There mus t be an absolute mi ni mum of 1 minute bet ween reel s. Five minutes is recommended.
3.5 Punch-ins
If drop-ins or punch-ins are necessary, make sur e the crossfade t i me on the machi ne is set to minimum. This is also another good r eas on for pre-formatting.
4 DTRS Machines – Care and Us e
SDDS Print Master Guidelines, Page 11 of 26
4 DTRS Machines – Care and Use
4.1 Models
DT RS machine ar e s emi -pr ofessional machines designed f or “large” home s tudios . T hey became qui ckly adopted as a s t andar d 8 track digital tape machine in European dubbi ng s tudios . It is still often the for mat of choice for moving mater ial between studios. T here ar e two mak es and s ever al models, the mos t important of which are listed below.
§
T ascam DA88 – the or i ginal
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Sony PCM800
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T ascam DA98
At present the SDDS masters must be i n standard 16 bit format. New hi gh bit rate modes are now available, but the camer a s i t es only have s tandar d PCM800s and DA88s so they can’t play back the new for mats .
4.2 L evels
Note that the DA88 and PCM800 are f act or y set so that +4dBu = –16dBfs. An allowance f or this has to be made if mixing with studio oper ati ng l evels other than 0dBu (as 0dBu = –20dBfs). The machi ne i ts el f can be modi fi ed for different levels, or console input/out put trims can be used. I f in doubt, check using the SDDS DT RS test tape. The DA98 has software s el ectable l evels for +4dBu =-16, -18 and –20dBfs.
4.3 Clean air
T here is a cooling f an in the DA88 and PCM800, which s ucks air through the machi ne. T here is no f ilter and t he onl y entry hole is the cassette dr awer. T his means that any dirt, cigarette s moke etc. in the air is pulled dir ectl y over the heads, which is very bad for the per for mance of the machine. It is recommended that the ai r around t he machines is kept as clean as possible, with no smok i ng in the same r oom. T here is a simple modi f i cation to change t he di r ection of the fan and add a f ilter. T he machine seems to be s lightly hotter after this mod, so careful checks must be made after war ds . Details are on Eddie Ciletti’s web s it e www. tangi ble- technology.com
4.4 Errors
Errors can occu r for a var i ety of reasons. Problems caused by dirty or worn heads can be checked for by playing back the mast er after recording. However, many recent problems we have found wer e all caused by tape path misalignment. This means that the tape will play back fine on the machi ne on which it was recorded, but causes errors on other machines.
4 DTRS Machines – Care and Us e
SDDS Print Master Guidelines, Page 12 of 26
4.5 Compatibility
Note that there i s no di fference i n line up pr ocedur e bet ween the T as cam DA-88 and the Sony PCM-800. Both machines use t he same S ony Hi-8 transport, and both machines are manufactur ed by T EAC.
4.6 Maintenance
Check the head hour s regularly (see bel ow) . Every 250 hours the uni t should be cleaned manually and the tape path alignment checked. T his should be per for med by an experienced engineer with the correct tool s and tes t tapes. Every 1000 hours the machine shoul d be fully aligned with probable r epl acement of the pi nch roller and r eel tables and the possible r eplacement of the heads . Real world ex per i ence has shown that the heads last for between 750 and 1200 hours.
4.7 Cleani ng
T he error rate of a k nown good tape should be checked r egul arl y (see bel ow – if the error LED lights it’s far too late!) . When the error rate begins to r is e, a cleani ng tape should be us ed and then the errors checked again. If there is no impr ovement, the machine shoul d be cl eaned manually and r e- aligned. Note that each pass of the cleaning tape will reduce the head life by appr ox imatel y 5 to 10 hours. Manual cleaning does not reduce head life, but there i s a danger that the head will be damaged (tur n anti-clockwise only) and als o the s tr ong possibility that the tape path alignment will be altered. It is therefore al ways advisable to check the alignment after manual cleaning.
4.8 Head hour display
T o i nvoke t he head hour display, hold S T OP+ PLAY whilst powering on. The di s pl ay will say “d XXXX” where XXXX is the tot al head hour s
4.9 Error rate di splay
Hold FF+ST OP+PLAY and power on. Within 2 seconds press STOP (for DA88) or PLAY (for PCM-800). The di s pl ay says “test”. Press REMOTE. Meters 1 and 2 now show head errors in play mode. A “tes t ” tape wi th a t one s houl d be made when the heads are new. The s t ate of the head and alignment can then be moni t or ed us ing this tape. Newly recorded tapes should als o be check ed for error rate per iodi cally. An “in-spec” machine will not show anything on the meter s .
4.10 T ape gets stuck inside
If errors occu r , sometimes the machi ne won’t eject, for “safety” r easons . To ej ect, enter test mode as above. Instead of pressing RE MOT E, press EJECT . T he tape will now ej ect. Next turn off the machi ne and back on to exit test mode. If the tape is damaged, do not continue t o us e the machi ne!
4 DTRS Machines – Care and Us e
SDDS Print Master Guidelines, Page 13 of 26
4.11 Hints for making pr int masters on DTRS machines
If possible play back the mas ter in a di fferent machine to which it was recorded. If a DA98 is available. This can be us ed i n “confidence” mode. This plays back the audio off tape whilst recording us i ng r ead after write heads . Bear in mind t he f ollowing
§
T he audi o output of the DA98 is delayed by 6 frames. T he pr oj ector must be advanced t o compensate for this.
§
T he tr acks are ar med i n pairs in this mode. Please ens ure t hat no noi se, hiss etc. is recorded on unused tr ack s , especially in a 5 . 1 format film. T racks 2 and 4 LC an d R C ar e s t ill played back in the cinema, so any noise pr es ent on them will be r epr oduced in the ci nema.
§
It is not possible to dr op- in/punch-i n in this mode.
5 Akai DD8 machines – Care and U s e
SDDS Print Master Guidelines, Page 14 of 26
5 Akai DD8 machines – Care and Use
5.1 Models
T here ar e two models of the DD8. Camera s it es have the mos t recent model, which is the DD8 plus.
5.2 Medi a
Masters should be s upplied on 2.6Gb MO car t r i dges , with 1 reel per side.
Not e: please check w ith the opt i cal transfer facility and t he f ilm distributor before using Akai DD8 MO di s cs for SDDS masters. Not all optical transfer
facilities have Akai machines. It is not a s tandar d requi r ement. If you’re not sure, mix to DT RS .
5.3 At the opt ical camera t r an s f er facility
T he audi o will be tr ans f erred di gi tally via AE S into the camer a. The camer a i s synchronised to a PAL video sync. T imecode i s used for positional information, and i s synchronised wi th a CB electronics Bi-phase to ti mecode conver ter . T he eas i es t and safest method i s for the camer a f acility to make a “s t r aight across” tr ansfer without re­assigning tr ack s , changing sync et c. Please bear this in mind when making master s .
5.4 T rack assignment
It would gr eatl y help the tr ans f er facility if the st andar d tr ack assignment is adhered to. T his can be found at section 1.2 on page 4. Tracks can be swapped inter nally when making cl ones etc. This can be set up in two ways . Either
§
“routing inputs” by pressing SYS T EM – INPUT S, or
§
“track mappi ng” by pressing S YS T EM – MORE – MORE – TRACKS. This lets you swap r ound t he out put assignments of recorded tr acks .
5.5 Synchr onisati on at the dubbi n g t h eat r e
Sampling F r equency 44.1kHz with Film speed 24 FPS. R emember! 44100 samples for every 24 frames of picture.
T he DD8 can be synchr oni s ed i n several ways.
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Video S ync ( r ecommended)
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Biphase
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Word s ync
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T imecode onl y (not recommended, and will not work with NT SC pu lldown)
5 Akai DD8 machines – Care and U s e
SDDS Print Master Guidelines, Page 15 of 26
If a P AL sync i s used, this is set up as follows
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Press SYSTEM – DI GI
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Set Sample R ate to 44.1kHz
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Set Digital Sync t o PAL Video s ync
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Press SYNC
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Set Ext. time s our ce to 25FPS
Please note t hat if NTSC s yn c i s used i n a “pulled down” set up, the s ampling frequency must also be pulled down to 44.056. T his is set up as follows.
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Press SYSTEM - DIGI
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Set Sample R ate to 44.056
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Set Digital Sync t o NT SC 29.97
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Press SYNC
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Set Ext time s our ce to S MPT E 29.97 nd
T hen record the mas ter in the us ual way.
5.6 L evels
Reference l evel = -20dBfs
It is important to s el ect the correct analogue oper ating level in the DD8, as the audi o will be di gi t ally transferred i nt o the camer a. Therefore l evels can’t be al ter ed at the optical transfer site. Use t he f ollowing t able as a gu i de.
Studio Operating L evel
Set Akai ref to
T one at Gives
+4dBu or 0VU -20 +4dBu
-20dBfs
0dBu or –4VU -16 0dBu
-20dBfs
+2dBu or –2VU -18 +2dBu
-20dBfs
-4dBu or –8VU -12 -4dBu
-20dBfs
T o change t he s etting on the DD8, perform the following.
§
Press SYSTEM – MORE – LEVELS
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T he l evel can now be changed
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Press EXIT. T he new setting mus t be s aved, either in the pr oj ect or as a defaul t in the F l ash ROM (recommended).
Please r emember that it is important to listen back to the S DDS master, to check for clicks, dropouts, bad connections etc.
5.7 Problems with MO dr i ves
One fault of the Akai DD8 is the f act that it doesn’t report disk reading errors. If it fails to r etri eve a f ile, it will simply mute one tr ack for, say, half a s econd, and t hen carry on as normal. Otherwise it may not play a t r ack at all. These pr obl ems are caus ed by:
§
Fragmentation – If a r eel contains a l ot of punch-ins or has been edited a l ot ,
the dri ve may have pr obl ems acce ssing all the s mall sections.
§
Dirt and age – it is extremely important to s er vice the dri ves regularly (see
below). For SDDS masters it is recommended that a newl y formatted di s c i s used, and the amount of punch-ins/editing is kept to a mi ni mum.
5 Akai DD8 machines – Care and U s e
SDDS Print Master Guidelines, Page 16 of 26
5.8 Drive s er vicing
T here ar e no official service i nter vals for drives, but servicing at least once a year is recommended. Servicing can only be perf or med by a s pecialist MO dr i ve s er vicing company.
Moreover, it is absolutely vital to have no s moking in the s ame r oom as these dr i ves . T hey are i ncr edibl y susceptible to air bor ne dus t and dir t . Cigarette s mok e combi nes the wor s t of all environments, as it is also s ticky. I f you have pr obl ems with MO dr i ves and s mok ing occu r s in the s ame r oom, this is almost certainly the r eas on for the problems.
6 SDDS - T he indus tr y' s best sounding for mat
SDDS Print Master Guidelines, Page 17 of 26
6 SDDS - The industry's best
sounding format
Sony Dynamic Digital Soundâ (SDDSâ) is the motion picture industry's most advanced digital sound format, designed exclusively for cinema presentation. In developing SDDS, Sony applied decades of innovative experience in professional and home audio to deliver
the highest quality sound presentation. SDDS has been engineered to give filmmakers increased creative freedom and ultimately to preserve the integrity of the master soundtrack. With SDDS, today’s moviegoers can now experience a film's sound exactly as heard by the director and sound engineers on the mixing stage.
6.1 Hear the Difference
Digital sound has changed the way people see movies. The clarity and vibrance of SDDS truly heightens the movie going experience. While other digital formats are limited to the same
5.1 channels as home systems, SDDS provides movie audiences with up to eight channels of crystal clear discrete audio. The additional two channels increases sonic detail and headroom adding impact to the presentation.
6.2 System Basics
SDDS is a sound-on-film format comprised of the SDDS soundtrack, optically printed on both edges of 35mm film and the SDDS playback hardware – a reader and processor. As the film is projected, the SDDS soundtrack is scanned, its data is processed, and ultimately converted into analogue audio signals for the cinema's loudspeakers and amplifiers.
6.3 SDDS Products
Sony manufactures a range of products that fit the exhibitor's needs. For new cinemas, there is the DFP-D3000 system that includes analogue and control functions and can serve as the central processor in any cinema, also available as an analogue only processor.
For retrofit applications there is the add-on DFP D2500 that simply
adds SDDS to any existing system.
Both systems use the DFP-R3000 Reader to scan the soundtrack. The reader mounts to the top of any 35MM projector.
6.4 Big Sound for the Big Screen
The days of narrow ‘shoe box’ small screens are over. Today, the emphasis is on making cinema going an event. There is a trend towards building, larger, wider screens to maximise the experience. SDDS enables filmmakers and theatre owners to fill big auditoriums with six or eight channels of discrete digital sound through five screen loudspeakers, two surround channels and a full-frequency sub-woofer channel. The glory days of 70mm big sound have returned with SDDS. None of the latest home theatre environments can compete.
6 SDDS - T he indus tr y' s best sounding for mat
SDDS Print Master Guidelines, Page 18 of 26
6.5 Fur t her details – Why is it the bes t sounding syst em?
In normal operation the S DDS playback equipment uses both sides of the film for playback. However, if one s i de i s damaged, the uni t will play in “digital concealment mode”. This uses extra back up t r acks for the l os t information. There i s a backup centre and s ubwoofer . T he l ef t and r ight channels are mix ed to cr eate l ef t mix backup and r i ght mix backup. T hese ar e played thr ough the appr opr i ate s peaker s at coded volume l evels . T he effect of going i nto “DCM” i s seamless. There i s always a di gi t al centre s o di alogue i s not disturbed. The two s ides are s epar ated f r om each other by about 17 frames.
T he data r at e off film is 2.2Mbits/sec, rather than 370kbits/second.
T he data compr ession is Sony’s accl a i me d AT RAC, used i n br oadcasting and i n minidisk players. The compr ession ratio is only 5:1, rather than 10:1 or 13:1.
T here is no data s har i n g between channels , all channels are f ull range 20kHz (even the subwoof er ) .
T he tr ack is printed i n the cyan layer. This is the deepes t layer and ther ef or e the mos t resistant to scratches. T he r eader s also us e patented di ffuse light, which also counteracts scratches. In normal use, with a well printed t r ack , the S DDS track will last as long as the pictur e.
T he cinema equ i pment is built to S ony’s high broadcast standards. It features 28 band digital EQ on all channels (2 band paramet r i c on the s ubwoofer). All I/O is balanced.
T he pi ctur e below shows the high resolution, small dot size of SDDS (on the l eft) .
6 SDDS - T he indus tr y' s best sounding for mat
SDDS Print Master Guidelines, Page 19 of 26
6.6 T est imonials
“Eight channel SDDS is awesome! I t makes a huge di fference on Pear l Harbor. I ’ve never heard a movi e s ound s o r eal . By all means, seek out a t heat r e f eat ur i ng S DDS 8 to exper i ence Pear l Harbor the way we i n t ended i t. ”
Michael Bay, Director, Pearl Harbor
“T he s ens e of being t otally enveloped i n hi gh-detail sound was particularly noticeable on this (SDDS 8) soundtrack”
François Groult, chief sound mixer,
“T he Messenger: The stor y of Joan of Arc”
“While the i ncr eas ed ‘s cr een resolution’ does indeed hel p wi th the defi ni ti on of busy scenes, five channels have as much place on quiet films such as ‘Erin Brockovich’. I always find t hat just having thr ee s cr een s peaker s on inti mate films forces me t o play too many el ements in the cen t r e hor n; otherwise, it’s distracting to have s ounds banging around t he exi t signs near the lef t and r i ght speakers. With SDDS, I can us e the lef t - cent r e and r i gh t - cent r e s peaker s for a n at u r al - f eeling, narrow s t er eo i mage throughout the whol e movi e, going wi der as necessary for exterior scenes.”
Larry Blake, supervising sound edit or & rerecording mixer,
Erin Brockovich
“Movie t h eatr es equipped t o pr es ent films in eight full channel s can build an d mai ntai n a gr eat er marketing edge over home t h eat r es . ” “Listening to the t hr ee- channel music became an annoying and di s tr acti ng disappoi nt men t , even with a 12 foot (wide) screen. Obviously my ear lier notion had been mis taken. T he S DDS eight-channel advantage will work in any theatr e.”
John F Allen, Boxoffice 1997
7 Dolby level versus operating level. Historical notes.
SDDS Print Master Guidelines, Page 20 of 26
7 Dolby level versus operating level.
Historical notes.
T he current standard for digital cinema s ound has a headr oom of 20dB above the studio r efer ence level. T his is usually 0VU in USA/France/S pain/I taly and 0dB u in the UK. If you look closely at a VU meter, 0VU is also marked as 100% . It now seems ludicrous that –20dB should be mark ed as 100% . However, when the meter was first invented, it was decided, for safety that there would be at least 10dB of headroom above thi s 0VU mark. This is because t he meter integrates the l evel over time and gives an average readi ng. It will miss instantaneous peaks. It therefore t ends to under read, depending on progr am mater ial. In the f ilm wor l d the fl ux level of magnetic f ilm was set at 0VU=185nWb/m. This allows roughly 10dB of headroom, remembering that maximum level on magnetic t ape i s not a s t r i ct l y defined poi nt, but that the ons et of saturation and di s tor t ion is gradual. This reference l evel of 0VU then translated to an SPL of 85dBc i n the cinema. With the advent of digital recording there i s no “ons et of tape s aturati on grey area” s o it is even more impor t ant to have l ot s of headroom to allow f or instantaneous peaks. 20dBs was decided on, which s eemed to s ui t the instantaneous peaks found in film s ound t r ack s .
In the UK the film meter i ng hi s t ory is slightly different. Reference l evel practises tend to come fr om the br oadcast sector and t he BBC i n particular was a gr eat setter of standards. Here you are t o f ind BBC PPM met er s . Marked fr om 1 to 7, with the higher numbers being 4dB s apart. PPM4 is usually 0dBu, PPM5, 0VU. The r efer ence level is usually 0dBu, PPM4. T he maxi mum (broadcast) level is then PPM6, 8 dBs above reference l evel. PPMs catch all the peaks so give a tr uer picture of the level . T ape fl ux levels can be s et much higher . 0dBu=200nWb/m was the s t andar d agr eed on for magnetic f ilm. T hese meter s are ver y convenient for mixing engineer s – dialogue peaks about 4 and mus ic about 5 is a s i mpl e maxi m.
When Dolby began their involvement with film s ound and noi s e r educt ion in the 1970s, they found a di fference of 0.75dB between USA and U K. This is acco un t ed f or by the difference between 185nWb/m and 200nWb/m. T he s imple r emedy for this would have been to change t he f lux level alignment of the mag machines , but in some cases the electrical operating l evel was changed i ns t ead, with potentially confusing r es ults .
In a U S A s t udi o, operating level and “Dol by level” are al ways the s ame. But in Germany still today, a s i t uat i on exists where Dol by level is -4.75dB with respect to operating level . The reas ons for this are pur el y histor ical and caus e enor mous confusion. German broadcasting tr adit ionally used t he DI N system wher e t he ref er ence level was the maxi mum broadcas t level. This was set for +6dBu=320nWb/m on magnetic f ilm and T ype 1 PPM met er s were us ed. T o make a wor l dwi de f ilm, the reference t one has to be 185nWb/m, which then equals 85dBc i n the ci nema. It was decided to keep the + 6dB= 320nWb/m standar d and then record tone at –4.75dB with respect to r efer ence l evel, this equates to 185nWb/m. This was then called “Dol by Level”. This all worked fi ne, but with the ons et of digital cinema s oundt r ack s , a bi z arre
-4.75dB=-20dBfs scenario was produced and t he r eas ons why are bei ng los t. T o counteract this, Dolby is now r ecommending t hat new s tudios follow the “Amer i can” system of having the s ame Dolby level and r efer ence l evel. T his makes sense as the DIN maximum sys tem has now largely disappear ed in the f ilm indus tr y.
8 Subwoof er s
SDDS Print Master Guidelines, Page 21 of 26
8 Subwoofers
- taken from tech note T N99051701 “setting the s ubwoof er s ”, by Craig Connelly
8.1 I nt roduct ion
T he topi c of setting s ubwoofer levels is the s ubj ect of numerous articles and even more numer ous opinions, but of only a s i ngle pr opos ed s tandar d ( S MPT E RP 200, and IT U 10-11R/T emp/11-E). There ar e many reasons for this. First, the us e of the moder n digital audio s ubwoofer is unique in comparison to the other channels and i t is recorded with a di fferent monitoring r efer ence. The pur pos e of the s ubwoofer has changed wi th the evoluti on of cinema s ound, from compensating f or the poor low frequency response and bass power capability of older screen speaker s, to addi ng power to low fr equency effects even in theatres having full range s cr een s peakers and capable amplifiers. Secondly, different post production facilities and even different engineer s have followed their own alignment conventions. Finally, equipment and even meter standards are di fferent when comparing the US A, Europe, and els ewher e. T his wordy article i s only an overview and i s not meant to compr is e a s peci fi c calibration process or set of instructions.
8.2 Setting t he acous t i cal reference l evel on the dub st age.
A s i gnal , generally wide band pi nk noise, is sent through the dubbi ng cons ol e to each of the monit or i ng s yst em’s screen s peakers at the electrical reference level (also known as Dolby L evel). Using a r eal time t hir d octave analys er , the moni tor system is adjusted for the pr eferred acous t ical response at each loudspeaker, given the properties of the l ouds peaker , the r oom, the s cr een, and t he “X-cur ve” of SMPT E 202M. The electri cal gain of each channel in the monit or ing s ys tem is then adjusted t o give an acoustical reference level in the r oom from each screen speaker.
8.3 Setting t he subw oof er acoustical gain using a s cr een speaker as a
reference.
T he channel used f or subwoof er or LFE (low frequency effects) in the dubbing theatr e is then adj usted as above, except that the S PL is measured di fferently. To make this adjustment properly, a mul t i - channel real time analys er must be us ed. Analyser bands in the fl at-r es pons e r egi on of a s cr een speaker (generally, the centr e s peaker ) are taken as a r efer ence. T hese bands will not individually measure 85dB SPL, but will be somewhat less, depending on the bandwidt h of the analys er ’s bands, typically about 70 dB SPL for a 1/3 -octave analys er as required by SMPT E 202M. This flat-response region, between the low fr equency roll off caused by the l ouds peaker cabinet and the high fr equency roll off due to the s cr een and X- cur ve, is referred to as the in-band (acoustical) response of the monitor speaker. T he s ubwoofer electrical gain is adjusted such that the anal ys er channels in its in-band r egion are 10dB greater than those in the screen s peaker’s in-band regi on. This is referred t o as “10dB of in -band gain” (subwoof er level relative to each screen s peaker level).
8 Subwoof er s
SDDS Print Master Guidelines, Page 22 of 26
4063100
160
250
400
6301K1.6K
2.5K4K6.3K
10K
16K
Center channel loudspeaker response
4063100
160
250
400
6301K1.6K
2.5K4K6.3K
10K
16K
Digital subwoofer (LFE) channel response
10dB higher SPL
T he meas ur ement is made acous t i cally, not electrically. Typically, each band of the analyser in the pass band of the s ubwoofer will then measure about 80 dB SPL. If a screen speaker and the L FE subwoof er loudspeaker are each measured wit h a wide band SPL meter, the s ubwoofer will typically measure appr ox i matel y 5.5 dB higher.
8.4 W hy we do it this way.
T he r eas on for lowering the electr i cally recorded l evel of the s ubwoofer channel and making it up by turning up the playback gain dates back to 70mm film. T he s ubwoof er recording level was lowered t o pr event saturation of the magnet ic t r ack and the playback gain was increased to compens ate. The l oss of signal to nois e per formance was inconspicuous because the s ubwoofer signal was sent through a l ow pass filter and di d not reproduce hi ss. T his level difference conventi on has been retained in the digital world, where i t serves to give addi ti onal effective headr oom for the playback of low fr equency sound effects through the s ubwoof er loudspeaker.
8.5 W hat it means.
T he cons equence of having 10dB more acoustical gain in the s ubwoofer monitoring channel is that the dubbi ng engi neer will tend to tur n down the electrical recording level of the s ubwoofer by about 10dB compared to what she woul d have done wi thout the incr eas ed moni tor gain. However, unlike the s cr een speaker channels , the engi neer does not use a cons ol e met er to check the electr i cal recording level of the s ubwoofer (except perhaps to guar d agai ns t overload condi ti ons ).
8.6 Setting t he digi t al screen speaker s in the ci n ema.
In the cinema, the s cr een s peakers are adj us ted i n the al mos t same manner as they were on the dubbi ng s tage. This calibration, which encompasses the ci nema processor’s main fader, equalizers, power amplifiers, crossovers, loudspeakers, screen , and r oom r es pons e, is referred to as the B- chain alignment. Consider the digi tally driven loudspeaker alignment first, as it is the mos t important. An electrical reference signal, generally wide band pi nk noise gener ated wi thi n the cinema pr ocessor at a specific l evel , is used to align each of the s creen s peakers to give the des ir ed r es pons e (the X- cur ve or other reference r es pons e) and acoustical reference level for each individual speaker (again, 85 dBc, slow r espons e, measured wit h a wi de- band S PL meter). T his procedure t ies the cinema pr ocessor’s electrical reference to an acoustical reference in the cinema, similar to what was done on the dubbing s tage.
8 Subwoof er s
SDDS Print Master Guidelines, Page 23 of 26
8.7 Setting t he digi t al subwoof er in the ci n ema.
In a s imilar way as on the dubbi ng stage i n S tep 3, the l evel of the digi tal subwoof er is set by using a mul ti - channel real time analys er and adj us ti ng the electrical gain of the monitor system to achieve 10dB of in-band acoustical gain, relative to a s cr een speaker. T he cons equence of this adjustment is that signals which wer e r ecor ded appr ox i mat el y 10dB lower for the s ubwoofer will now play back in the ci nema at the same acous t i cal level as they did when the dubbing engi neer recorded t hem on the dubbi ng s tage, because the playback conditions have been acoustically matched between the dubbi ng s t age and t he ci nema ( as closely as variations in rooms and loudspeakers will allow).
8.8 Optical subwoof er defined.
T he opti cal subwoof er has a di fferent function than the digi tal subwoof er . It serves to enhance t he bass response of the opti cal playback. It is totally artificial, synthesized in the ci nema pr ocessor by combining the L , C ( -3dB), and R signals from the decoded optical Lt,Rt and s ending the s um through a l ow pass filter. The cut off frequency of this filter may be 50Hz, 80Hz, 100Hz, 120Hz or some other frequency, depending on the ci nema pr ocessor and the i ns taller’s judgement. A hi gh pass filter may also be applied, if it is not already a component of the opti cal preamplifier, to r educe low frequency artefacts caused by ground nois e t iming (GNR ) errors and s t r eaki ng nois e on the pr int. T he end r es ul t is a s i gn al containing fr equency components which over lap those bei ng s ent to, though not necessarily reproduced by , the s creen speakers. In Hollywood, the dubbi ng engi neer may not have listened to this signal on the dubbing stage ( i n part because t he DS 4 without a cat. 160 card does not create i t ) and so made no arti s ti c deci s i ons based on it. It is merely an enhancement created i n the cinema t o gi ve the effect of more bass extension in the s cr een speakers and has no correspondence to any discrete s i gnal on the dub s t age. Note that it also has a much lower dynamic r an ge than the digi tal subwoof er signal. The di gi tal subwoof er signal, in contrast, was creatively recorded on its own discrete channel (Sub or LFE) of the pr i nt master and i s used f or specific l ow frequency sound effects.
8.9 Setting t he opt ical subwoof er .
T he opti cal (analogue) subwoofer is adjusted to match the optical screen speakers and effectively extend thei r low frequency response, again using a mu l t i - channel real time analyser to compar e bands in the pass band of a s cr een speaker and the pass band of the subwoofer , and setting in-band acoustical levels acco r d i ng l y . In this case, there i s no in-band acous ti cal gain difference, as the s ubwoofer signal is just the l ow fr equency components of the s cr een speaker signals.
4063100
160
250
400
6301K1.6K
2.5K4K6.3K
10K
16K
Center channel loudspeaker response
4063100
160
250
400
6301K1.6K
2.5K4K6.3K
10K
16K
Analog subwoofer channel response
Same SPL
Full range s cr een s peakers need less help fr om the s ynt hesi z ed opti cal subwoof er signal than do ol der speakers with poor bass extension. Experienced cinema en gi neer s may chose t o r educe the nominal level of the opti cal subwoof er , lower the fr equency
8 Subwoof er s
SDDS Print Master Guidelines, Page 24 of 26
of its low pass filter, or even eliminate the s ynthes i z ed s i gnal altogether, depending on the capabilities of the scr een loudspeakers and the audi tor i um’s acoustical response.
8.10 Subwoof er polarity.
As a s i de not e, it is often difficult to deter mine the correct polarity of the s ubwoofer , digital or analogue. Even if pink noise i s sent to t he s ubwoofer and cent r e channels simultaneously, in many cas es there will be no appar ent difference i n combined wi de band S PL measurement when s witching s ubwoofer polarity. In the end t he bes t polarity may come down to an aesthetic j udgemen t on the part of the ci nema technician, based on listening to actual films.
8.11 R ule-of-t humb met hods.
Measuring t he l evel of a s ubwoofer with a wi de-band S PL meter is of questionable value except as a r ul e- of - t humb method t o r e-check a theatr e that has already been properly calibrated. T he r eas ons for this include the fact that the meas ur ed acous t i cal output of a s u bwoof er (or any loudspeaker system) depends on the bandwi dt h of the signal ultimately being meas ur ed. T hat will be affected by the bandwi dt h of the i nput test signal, any equalizer or low pass filter settings, the audi tor i um’s response, the loudspeaker cabinet response, and the accu r acy of the C wei gh t i ng r es pons e at low frequencies of the SPL meter used for the meas ur ement. A s ubwoofer signal with a wider bandwidth may measure t he s ame as another with a n arrower bandwidth but higher level (as indicated by analyser bands within the pass band of the s ubwoofer), using the s ame s peaker cabinet. Considering the DF P-D3000, the bandwidth of the pink noise s ent to the s ubwoof er is affected by a l ow pass filter that can be adj us ted from 80Hz to 330Hz—a di fference of three octaves or eight times in acoustical energy. No s t andards exist for such wide band S PL measurements of subwoof er s.
Although the meas ur ed S PL of wide band pi nk noise t hr ough the s ubwoofer will change i f the s ubwoofer ’s low pass filter is adjusted, this will not change t he actual playback level of the di gital LFE channel from film. So l ong as the filter frequency is not set too l ow, the s i gnal s recorded on the dubbing s tage will determine what is heard in the ci nema when the pr oper in-band gai n difference i s established acoustically, as previously described. This is why an engineer who us es a wi de- band SPL meter to set the di gital subwoof er level is engaging in s elf-deception. In gener al, a low pass filter setting for the digi tal subwoof er (LFE) of 125 Hz, 160 Hz, or even 200 Hz should s er ve i n most installations, and all settings should s ound the same when playing digi tal multichannel material. A l ow pass filter setting of 125 Hz will give a wi de band s ubwoofer SPL pink noise meas ur ement of appr ox i mat el y 91 dBc. T his rule-of- thumb r es ult is only appr oxi mate and s houl d not be used f or the pr i mar y alignment of a t h eat r e.
9 Glossary of T erms
SDDS Print Master Guidelines, Page 25 of 26
9 Glossary of Terms
T erm Also K nown As Descripti on
Sync pi p Head pop 1kHz tone of 1 frame
duration us ed for synchronizing s ound and pictur e
Domestic ver s i on Original version T he or i gi nal language
mix
M&E International version Music and s ound
effects only, no language specifi c dialogue
Dialogue premi x DX premix Only the dialogue
Left total, Right total LtRt, SR, SVA Matrixed “anal ogue”
track
Confidence pass Control Playback check
Overlap Pull Up Audio after the end of
a r eel from the s t art of the nex t reel, to facilitate manual reel changeovers
SPL Sound Pr essure Level Level of acoustic
sound in the air
dBfs DB full scale Level of a di gi tal
signal, where 0dBfs is the maxi mum level.
Punch-in Drop-in T he pr ocess of editing
a r ecor di ng by pressing t he r ecor d button whilst playing back
9 Glossary of T erms
SDDS Print Master Guidelines, Page 26 of 26
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