Film-Tech Forum ARCHIVE: Sony DFP-R2000 Problem

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Posted by Chase Taylor (Member # 778) on 09-20-2005, 01:29 PM:

I'm having a problem with my SDDS system (DFP-D2000 and DFP-R2000). I think I've tracked down the problem to the reader. I'm only getting the Left, Center, and Left Surround channel with normal play back. When I cover up the sound track side of the SDDS track at the reader I get all six channels (I assume that I'm getting the backup tracks from the other side. When I cover up the non sound track side of the SDDS track I loose all channels. I know there is probably some detail I've left out that you guys need. Thanks for the help.

Chase Taylor

Posted by Monte L Fullmer (Member # 2797) on 09-20-2005, 02:06 PM:

..wonder if you have an LED getting ready to poop out for that outboard track .. it does happen when the LED begins to fade.

A slick little trick is to cover up that one LED with black tape and let the inboard LED take over completely. Or, turn off the power supply that is driving that one LED..be easier.

-Monte

Posted by Brad Miller (Member # 2) on 09-20-2005, 02:10 PM:

No don't do that, because the "backup" tracks are of noticeably lower quality and that sounds terrible.

I've actually never heard of this so I unfortunately don't have anything to recommend other than to get out the scope and check the alignment on the reader.

Posted by Monte L Fullmer (Member # 2797) on 09-20-2005, 02:20 PM:

quote: Brad Miller
because the "backup" tracks are of noticeably lower quality and that sounds terrible.

..interesting. Wonder why that the inboard track is more crappier than the outboard track. You think that SONY would want the same for both tracks so there wouldn't be that much of a noticable difference between the two. Would it be a processor adjustment then per each track that could be out or something.

Granted, I'm just guessing here since I haven't worked with SDDS and that format is extremely rare to find around here.

thx, Brad. - Monte

Posted by Brad Miller (Member # 2) on 09-20-2005, 02:28 PM:

4 of the 8 channels are full quality and the other 4 are low quality on each side of the film. If the inboard side fails, the outboard can continue. During normal operation the 4 high quality tracks from each edge are used together to obtain 8 high quality channels.

Posted by Monte L Fullmer (Member # 2797) on 09-20-2005, 03:08 PM:

Ouch! that kinda sucks the big one then when one side starts to crap out.

But, another question then: why of the two different qualities - high and low? Wouldn't you think that, once again, SONY would want all 8 tracks, each from both sides, to be equal in quality?

(unless it's a go-figure thingey).

thx-Monte

Posted by Daryl C. W. O'Shea (Member # 1303) on 09-20-2005, 03:38 PM:

I'm sure they would, but thankfully SONY has no control over physics. Thus they can only fit what will fit, and that's 4 high quality and 4 lower quality tracks per side.

Posted by Chris Trainor (Member # 9) on 09-20-2005, 06:51 PM:

Monte:

Not enought real-estate on the edges of the film to fit in the data rate needed for all high quality tracks and backups. Sony however is already running the highest bitrate for digital sound on film (in theory DTS can be higher, but for regular 35mm stuff doesn't choose to use that ultrahigh bitrate).

In theory with some of Sony's newer compression codecs that are out there they could come out with a model that probably had higher quality sound on all tracks including backup, but I dont' think anyone would buy it after the shafting they got from Sony on SDDS. [Smile]

--chris

Posted by Monte L Fullmer (Member # 2797) on 09-21-2005, 04:18 AM:

Thx all, for your help on this topic for me, since I'm in the dark with SDDS

Yet, another question: I've heard of some theatres that can run SDDS without any problems, yet I've heard of other theatres can run SDDS for only a week or two then big time dropoffs in error rates to where there is output issues - all related to where the tracks are on the film: where there is most wear being on the edge of the print.

Are both above right, or is an individual theatre problem?

thx-Monte

Posted by Dominic Espinosa (Member # 2122) on 09-21-2005, 04:56 AM:

quote: Monte L Fullmer
..wonder if you have an LED getting ready to poop out for that outboard track .. it does happen when the LED begins to fade.

I know this is simple but it hasn't been asked yet. Have you tried other SDDS tracks? Does it do it on everything? I've actually seen 2 trailers and a feature reel with bad SDDS tracks on them in the last month.

As for the actual issue I'd try Monte's original suggestion and Brad's suggestion of checking reader alignment.

The manual's in the Manuals section (duh) and it has everything I've ever needed for our SDDS unit outside of some issues we had with our APR board which were resolved by Cinematech.
I don't happen to have their number handy but I'll look for it tomorow at work.

--Dom

Posted by Brad Miller (Member # 2) on 09-21-2005, 05:45 AM:

Well Monte, you're right and you're also right.

Some projectors are notorious for being able to run a film dry and damage the SDDS / SRD tracks very quickly (Christie is generally the worst) and other projectors tend to be able to run a film for thousands of passes dry without any noticeable abrasion (Century is known for this). However ANY projector can run an SDDS / SRD track indefinitely if FilmGuard is used on it.

The reason for the quick wear on some projectors when running the film dry is because if there is any dirt or emulsion deposit on the gate it acts like a knife and literally scrapes the emulsion right off...which means there is missing data on the audio track. A print that is properly lubricated doesn't "shed" during projection, so afterwards the projector is still essentially clean. A clean projector at the end of a show is what it takes to be able to run SDDS / SRD prints for any length of time.

Posted by Chase Taylor (Member # 778) on 09-21-2005, 10:33 AM:

Same problem on each print I try. I've never aligned an SDDS reader only a SRD reader I'm sure it is not much different. Thanks for the help.

Chase Taylor

Edit:
Is there any documentation on how to align the DFP-R2000.

Chase

Posted by Mark J. Marshall (Member # 1409) on 09-21-2005, 12:13 PM:

Edit: Correcting myself. The SIDE channels are mono. That is, left, left-extra, and left-surround are mixed as a single LEFT backup track, and then there is also a backup center channel that's compressed. On the other side, right, right-extra, and right-surround are mixed as a single RIGHT backup channel, and there is also a compressed subwoofer backup track. So each side contains four full range channels, and TWO backup tracks.

Which makes things really interesting in an eight channel setup because the left-extra or right-extra channel (depending on which side failed) lights up all of a sudden.

If I have one side of SDDS failing, I drop things out to analog. Even SR played through A sounds better than SDDS in DCM mode in my opinion.

Posted by Michael Schaffer (Member # 1204) on 09-21-2005, 12:33 PM:

I think you are right. One side (the analog soundtrack side) contains RE, R, Rs and Sw. The other side contains Ls, L, LE, C.
Each side only contains a mono sum of the opposite side plus the C and and Sw channels are mirrored 1:1 on the respective other side. Are the C and Sw backup channels actually more compressed than the regular C and Sw channels? I don't remember. Anyway, so there are 6 channels total on each side.
The problem you described with the extra channels suddenly lighting up is certainly quite well audible when you have a print that is actually 6 channels. If possible, I would switch off the amps or mute the LE and RE tracks in the setup software when you play 6 channels. Then it is much less noticeable.

Chase - in addition to the SDDS literature Brad provides here, all the manuals are on sdds.com.

Posted by Chris Trainor (Member # 9) on 09-21-2005, 01:31 PM:

Chase, right here on Film-Tech is the manual titled: SDDS adjustment of ccd output gain for DFP-R2000 (SCTB98-001)

That tells you how to align a R2000. The only 'special' equipment you generally need is a 100mhz scope (not too hard to find these days).

--Chris

Posted by Dominic Espinosa (Member # 2122) on 09-22-2005, 04:33 AM:

...And if you can't figure it out, give the guys over at Cinematech a call. They're pretty damn useful:
888-250-SDDS (7337)

--Dom

Posted by Steve Guttag (Member # 268) on 09-22-2005, 09:26 AM:

The back up Center and S/W channels are not compressed any more than the normal ones, as it has been explained to me.

You should NOT see the LC and RC channels suddenly pop up when in DCM (Digital Conealment Mode). The Back up channels (aka "prime" channels) are indeed a mono sum but there is also data to have the appropriate level of the prime channel play out of the various speakers however I think it is only on a 256 level scale. Thus, listening to just the back up channels will simulate the original but it is a bit choppy sounding and it is a mono mix.

The way the concealment works is that the level coming out the channels should not be dramatically different than main channels. Thus, when a splice goes through it doesn't call attention to itself. If you merely block one "eye," you will definately hear the level jumps...it is meant only for a momentary back up, not a continual thing. Very few people pick it off when a splice goes though. Minde you, a spilce will have all chanels go though Digital Concealment though not at the same time since SDDS staggers the tracks.

Posted by David Stambaugh (Member # 1102) on 09-22-2005, 12:01 PM:

quote:
Mind you, a splice will have all channels go though Digital Concealment though not at the same time since SDDS staggers the tracks.

Does this happen regardless of how carefully the splice is made or what kind of splicing tape is used? The SDDS shows I've seen have never had detectable dropouts around the reel-change splices (lab splices are another story). The first "Lord of the Rings" comes to mind. I didn't notice a single dropout during the entire 3 hours. "Spider-Man" was shown in SDDS-8 and I didn't notice any sound anomalies in it. If it's going into concealment mode, it seems to be pretty much inaudible, at least in those limited examples. Admittedly there's only 1 theater around here with SDDS.

Posted by Steve Guttag (Member # 268) on 09-22-2005, 04:45 PM:

Yes, every splice will result in Digial Concealment on both sides of the film but not at the same time (due to the staggared tracks). So yes, you've been fooled too by the Sony DCM method.

Posted by Mark J. Marshall (Member # 1409) on 09-22-2005, 05:48 PM:

quote: Steve Guttag
The back up Center and S/W channels are not compressed any more than the normal ones, as it has been explained to me.

quote: SDDS DFP-D2000 Operation Manual Page 2(E)
In addition, the following four channels of compensation signals are read from the opposite sides of the film.
P side

Rmix (mixed R, RC, and SR)
SW' (compressed SW)
S side

Lmix (mixed L, LC, and SL)
C' (compressed C)

quote: Steve Guttag
You should NOT see the LC and RC channels suddenly pop up when in DCM (Digital Conealment Mode).

We do indeed see the LC and/or RC channels come alive on the LED display when one side is failing, but only on the eight channel setups. Are we the only ones that have that "feature"?

Posted by Steve Guttag (Member # 268) on 09-22-2005, 07:15 PM:

Mark...the manual does claim as you say. i will therefore go with that since my information is strictly from memory in a class once upon a time.

As to your experiences with LC and RC turning on in DCM...I doubt that your unit is unique and it probably does that on all of them...however, again, as it was explained to me...in DCM, the prime channel is indeed a mix of the three channels (Left or Right) and that contained within the data is a rough level for all three so, in theory, if LC contributed zero to the L' back up track, it should play back the L' signal at zero...apparantely theory and reality have drifted a bit. It is pretty moot now that the format is essentially dead from a development standpoint. However it performs is how it will perform so long as your unit is in operation (don't be looking for upgrades).

Posted by Chase Taylor (Member # 778) on 09-24-2005, 07:33 PM:

I followed the instructions and got the results that were shown on the form, but still have the same problem. Any other ideas?

Chase Taylor

Posted by Monte L Fullmer (Member # 2797) on 09-25-2005, 01:56 AM:

Edited post. A tech needs to come there and really tune up that condition of yours then. Sounds like it's beyond your limits in searching out this problem.

[ 09-25-2005, 12:07 PM: Message edited by: Monte L Fullmer ]

Posted by Aaron Sisemore (Member # 145) on 09-25-2005, 04:04 AM:

quote: Chase Taylor
I followed the instructions and got the results that were shown on the form, but still have the same problem. Any other ideas?

Call Robbie Hidalgo at Cinematech TOLL FREE at 888-250-SDDS I believe he is ext 705 but if you sit thru the whole voice message he will tell you to wait or press a number to get him directly.

Explain the problem to him, he will do his best to talk you thru it right over the phone.

-Aaron

Posted by Michael Schaffer (Member # 1204) on 09-25-2005, 11:10 PM:

quote: Chase Taylor
I followed the instructions and got the results that were shown on the form, but still have the same problem. Any other ideas?

Yes: change over to projector 2 input and see what it does then. The symptoms you describe are very strange. The problem does not seem to be a reader problem, but how the data from the tracks are handled.

I don't remember how you change over, it may be as simple as connecting two pins on the automation input as with Dolby processors, or you may be able to do it from the software. It's been too long for me to remember, so you have to look it up yourself.

The level information for the backup tracks is supposed to work - in theory - exactly as Steve described. But I have seen the effect of the Extra channels waking up in DCM mode myself many times.

Posted by Steve Guttag (Member # 268) on 09-26-2005, 06:29 AM:

To switch to projector 2, connect pin 2 to pin 14 on the automation connector. It will make the switch after the programmed delay (settable in software but standard at 7 seconds).

Posted by Chase Taylor (Member # 778) on 09-26-2005, 07:24 AM:

Thanks guys! I'll give it a try.

Chase Taylor