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Author Topic: What causes DTS to drop out at reel splices? Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 12-19-2002 07:55 AM                    Does SR-D (or SDDS for that matter) actually read through (clear) splicing tape? Hmm...it would be an interesting test to run a tape down enough film to make a loop.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 12-19-2002 09:23 AM                     I'll wager it wont track. Particularly if you get the tape on the side the contacts the drum. The thickness of the tape alone will push the soundtrack out of focus. Steve  |  IP: Logged Mark J. Marshall Film God Posts: 3188 From: New Castle, DE, USA Registered: Aug 2002 posted 12-19-2002 09:41 AM                    quote: in a situation like this everything is relevant.... until it is removed by elimination. OK, ...I'm eliminating it. I'm assuming that he means am I splicing reels or changing over to reels. The problem occurs on reel splices not reel changeovers. And not to be too picky, but you can run platters and changeovers at the same time. quote: It is best to have the DTS reader the last thing on top of the projector head It is. The order is Kelmar bracket, SDDS, then DTS reader. Looks pretty funny that way IMO, but that's the way it is! quote: Please make sure that your OFFSET is not more than '70'. It is. The DTS is the last thing in the film path just above the projector head. Here's a very technical question. What are the lengths of the different "bits" that can appear on the DTS time code? The little white dots and dashes I'm talking about. What are their lengths? I'm thinking if there a problem something like: 1) a small gap in the splice between the two edges of film that lets light through, or 2) the timecoode on one of the reels is offset by a couple of millimeters, or 3) the splicer has sufficient play in it to add or subtract a milimeter or two, or something that would offset the two timecodes sufficiently to make a "dot" look like a "dash" if you will, or vice versa, then perhaps what's happening is the DTS is picking up a bogus serial number ID on the reel and therefore STOPPING the playback because it doesn't have the sound data for that bogus serial number. Consider a morse code "H" which is "....", and lets say the first two dots are on the end of the first reel, and the last two dots are on the beginning of the next reel, and the operator makes a slightly poor splice by leaving a small gap in between. "..| |.." may end up looking like ".-." ("R") instead of "...." ("H"). Or ".| |." may look like "..." instead of "..", etc. Or take it the other way - if you overlap, you could have a "..." instead of a ".-.". That's my theory anyway. I guess the question for Karen is: what has to happen in order to make the DTS stop playing "immediately". Immediately is the key word because as soon as the splice goes through, the sound stops. Then after two or three seconds, it comes back. BTW, the DTS code is there. Someone suggested that the code would not have started in time on the film and that's not the case. It's there. Thanks for the feedback! Mark  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 12-19-2002 09:55 AM                    ok here is one final suggestion. Are the CD discs clean. Free of scratches and finger prints?  |  IP: Logged Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 12-19-2002 09:57 AM                        I once had a print that consistently dropped out at a specific point. It turned out that the film itself was defective (?) It was too fat! It wouldn't fit in the splicer right. A few feet into the reel it was ok but the first bit was weird. I don't know what would cause this and it's probably not your problem but interesting just the same. The effect was that it would lose signal. (The green led on the reader would go out) The reader I had didn't have the "Don't adjust this adjustment" sticker on it so I could adjust the tracking on the fly and then adjust it back until I finally got a new reel and it cured the problem. Weird  |  IP: Logged Mike Rendall Film Handler Posts: 78 From: Southampton, Hampshire, UK Registered: Nov 2002 posted 12-19-2002 10:45 AM                     We have had the problems with SR-D dropping out at reel ends before mainly because we run second run stuff and previous projectionists either stand on the end of reels and get them so dirty or paint the edges with so much tipp-ex that it completely obliterates the SR-D and some of the analogue track also! Now, our SR-D rarely drops out even on old prints. I heard a rumour years ago that the software on the flash rom on a DA-20 was upgraded by a film (I think it was independance day) and since has better error correction?? For information, we have CP65/DA20/Dts6D.  |  IP: Logged Karen Hultgren Master Film Handler Posts: 492 From: Agoura Hills, CA, USA Registered: Mar 2000 posted 12-19-2002 06:57 PM                        In DTS's case, 25 fps should make no difference. Karen at DTS khultgren@dtsonline.com  |  IP: Logged Karen Hultgren Master Film Handler Posts: 492 From: Agoura Hills, CA, USA Registered: Mar 2000 posted 12-19-2002 07:18 PM                        Mark, A splice will not cause a drop-out in DTS. As mentioned, if the offset setting in the player is above '70', that can cause a momentary drop-out. If the offset is over '70' that is enough to empty the buffer of timecode. The buffer can hold up to 4 seconds of timecode. When it empties, the DTS player will drop out. So, if the outgoing reel ends and the incoming reel's timecode hasn't made it to the buffer before it empties, the unit will momentarily drop out until the buffer refills. Please check your offset. It is under the front plate on DTS 6/-6D players. It takes more than 4 seconds of no timecode or unreadable timecode for the player to drop out. You will probably see the reader start blinking or go out before the drop-out occurs if the timecode is unreadable. If you are getting drop-outs with every print, then check your offset. To test that the player's buffer is working properly, temporarily block timecode and verify the DTS player does not to analog drop out for 4 seconds. If only one reel change keeps dropping out, then you probably have a bad reel and you need to get a replacement from the distribuator. Karen at DTS khultgren@dtsonline.com  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 12-20-2002 03:17 AM                        Question: If there is some film missing, at a bad splice or one with cut reference frames, the dts processor has to leap ahead when this occurs. Is it not just possible that there are rare situations when the processor`s software fails to make that leap and drops out for a very brief moment to adjust the audio playback to the incoming timecode? We all know how complex software processes are and how unforeseen things happen even in a generally very reliable system...  |  IP: Logged Mark J. Marshall Film God Posts: 3188 From: New Castle, DE, USA Registered: Aug 2002 posted 12-20-2002 09:57 AM                    Karen, et al... If I were to take a DTS encoded LOTR trailer, and chop it in half at a particularly loud point and splice the beginning of a DTS encoded Star Trek trailer to it, what's supposed to happen when that splice goes through assuming both trailers exist on the CD in the drive? Would it keep playing LOTR for four seconds to empty its buffer even though it should recognize the ST trailer pretty much right away? Or would it stop LOTR immediately right at the splice and start playing Star Trek?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 12-20-2002 04:30 PM                     It would immediately jump to Trek.  |  IP: Logged Karen Hultgren Master Film Handler Posts: 492 From: Agoura Hills, CA, USA Registered: Mar 2000 posted 12-20-2002 05:05 PM                        Mark, Once the splice goes through, the sound would immediately change. The timecode for the incoming trailer would already be loaded into the buffer. Remember the the reader is mounted onto the projector *before* the picture gate. That ia plenty of time for the buffer to be loaded with timecode from the incoming trailer. The test I told you about was to block timecode and test to see if the DTS sound stops after 4 seconds. This tests that the buffer is storing and emptying properly. Karen at DTS khultgren@dtsonline.com  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 12-21-2002 05:04 AM                        *EDIT* After I posted this I re read the thread and realized that Mark did say you can run both c/o's and platters not Can't like I thought. Im going to leave my post here as both a monument of stupidity and a lesson that you should always re read stuff before you make a reply. It also gives everyone the chance to laugh at my expense (I like to bring a smile to peoples faces). Sorry Mark! I just looked at this thread today and found it very interesting. I saw that Mark said that you cant run changeovers and platters at the same time. Why cant you? You could build reels 1-3-5-7 on a platter leaving the heads and tails on the print just splicing head to tail (in frame of course) and use reels for 2-4-6 and changeover from the platter machine to the reels. Why would you ever do this? I dont know but you could if it tickled your pickle... (maybe you get a replacement reel 5 mins before the show or something and this would be a creative way to show the new reel without delaying the start time??? or you have a Miniwind platter and a really long movie just use the last reel as a changeover if you are capable) Sorry for yet again bringing a thread off topic  |  IP: Logged Mark J. Marshall Film God Posts: 3188 From: New Castle, DE, USA Registered: Aug 2002 posted 12-23-2002 08:39 AM                    quote: It would immediately jump to Trek. That's why I think it's misreading the time code and thinking the reel id is something other than what it actually is. I'm going to try some blocking the time code experiments at the splice to see if I can get it to stop dropping, and let everyone know what happens. It would be really interesting to see a log of some sort from the DTS to see what it's actually thinking that it's reading. Sean: That's funny! I've done that too, and I have to say that it's mighty big of you to leave it up there. I worked at the Univ of MD College Park theater and we would have at some points three movies built up on a five tier platter, and the trailer pack built up on a large reel. And we'd change over from the trailer reel to the platter. We did that because since we only had one theater, we only got one copy of each trailer. We could also change over from 35mm trailers to a 16mm feature, or whatever which was kind of cool also.  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 12-23-2002 12:03 PM                        It would also be very interesting to know when exactly the dropouts occur. Exactly on the splice or just before or after it. Is it always the same reels on which the system drops out?  |  IP: Logged

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