Film-Tech Forum ARCHIVE: 35mm Digital Sound Playback Preference?

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Posted by Phil Hill (Member # 371) on 04-24-2010, 09:26 PM:

If you have the required hardware and the print has the ability to playback Dolby Digital, DTS, and SDDS, which one would you choose as your 1st choice and why?

Posted by Bernie Anderson Jr (Member # 410) on 04-24-2010, 09:37 PM:

DTS! Always liked the dynamics and the mix in DTS. Still remember the first time I've heard DTS in a packed theatre for opening night of Jurassic Park. When they played the flying dts disc logo before the film, the crowd went wild. Then SDDS and then DD.

Posted by Cameron Glendinning (Member # 3516) on 04-24-2010, 09:37 PM:

DTS due to better stereo effect in the surrounds than the same Dolby Digital track.
Please note Phil that I do not have much experience with SDDS

Posted by Steve Guttag (Member # 268) on 04-24-2010, 09:50 PM:

Easy...

SDDS. By far, the best sounding of the three. Every time I've done an A/B/C comparison of the three, having tuned them using the same analyzer, SDDS has always won.

Furthermore, SDDS, when available, has 5-screen channels (my preferred sound arrangement) and some talented recording engineers use it.

#2 for me is Dolby Digital, unless the print is beat. It has a pretty natural sound to it.

#3, DTS...it has always been too strident for me. DTS with EV speakers, in particular can be quite painful (if they are using the DH1 driver, like on the TS9040 or TS940). I don't understand the comment about DTS' surrounds...they are compromised since part of their frequency range goes to the subwoofer. Dolby and SDDS, on the other hand, have full range surrounds. DTS no longer needs to perform this economy to get the 6-channels to fit...however, for legacy processors, they still have to encode the subwoofers on the surround channels. DTS can also carry the torch on 5-screen channels, which they do for some 70mm reissues.

At the Uptown, years ago, when folks would ask what digital I was running, and I told them it was Dolby...they would bring up "compression" and such...so I told them I would randomly switch between Dolby and DTS during the show...then they would have to tell me which reels sounded best (I would switch sound on a changeover). Those that could tell (and many couldn't) would always pick Dolby over DTS without knowing it until I told them. They just had preconceived notions about Dolby having this horrible compression as compared to DTS.

Steve

Posted by Brad Miller (Member # 2) on 04-24-2010, 10:10 PM:

My findings have been the same as Steve's (provided the SDDS was done fairly...I never use the SDDS internal EQ as the pink noise is HF deficient which results in a shrill-sounding end product).

I do find SRD and SDDS to be very close, but SDDS does have an ever so slight edge. That being said I hardly ever run SDDS because at least I can get the Dolby processor repaired if it breaks. Not quite so easy with the SDDS.

DTS is a fine format, but it is the last on my list. The sound is sterile to my ears. As with Steve, blind listening ABC tests in my own screening room consistently produce the same results with other people. SDDS first, SRD second (some people can't tell the difference), but DTS always comes in as their last choice.

Phil, if you will get off of your ass and come visit me, I'll let you do the listening test for yourself. We still owe you a trip to Chuck-E-Cheese anyway. [Razz]

Posted by Peter Castle (Member # 1997) on 04-24-2010, 10:19 PM:

Definitely SDDS. Having had that choice for 15 years, I've found that SDDS gave the best sound and was the most likely to be still working on older prints. Maybe the EQ was doen better the first time for SDDS. DTS is just too much trouble, even if discs were never a problem for us - lip synch was always a worry, especially with two projectors. And Dolby was more than likely to drop out on prints we got - and more recently Dolby is poor, even on prints of good quality.

Posted by Phil Hill (Member # 371) on 04-24-2010, 10:42 PM:

quote: Grand-Poopie-BAH
Phil, if you will get off of your ass and come visit me...

I'm riding my ass "Francis the Talking Mule" to your abode and should arrive sometime in late summer. [thumbsup]

Save a pizza and a pizza boy for me. [Wink]

Posted by David Stambaugh (Member # 1102) on 04-24-2010, 10:53 PM:

My opinion doesn't count for s**t here since I'm a non-professional, but SDDS always sounded the best to me at the local Regal Cinema World 8 which had all 3 sound formats. That theater is gone now. Can't tell you why SDDS was better but it was.

Posted by Tony Bandiera Jr (Member # 2365) on 04-24-2010, 11:23 PM:

Those who know me well enough here will be shocked by my answer:

SDDS has the best sound to my ears.

DTS has always sounded good to me and I prefer it slightly over Dolby Digital which sounds a bit harsh to me (opposite of Steve's experience.)

Hey Phil, detour to UC Irvine and take a listen to my new screening room there, and I can introduce you to some hot college studs. [Big Grin]

Posted by Phil Hill (Member # 371) on 04-24-2010, 11:34 PM:

quote: Tony Bandiera Jr
...I can introduce you to some hot college studs.

Hubba Hubba! [beer]

Posted by Tony Bandiera Jr (Member # 2365) on 04-24-2010, 11:37 PM:

Thought that would get a rise out of you. [Big Grin]

Posted by Monte L Fullmer (Member # 2797) on 04-25-2010, 01:36 AM:

True, what I've heard that SDDS really can knock the socks off the other formats. Yet, DTS has the lowest compression rate at 4x, whereas SRD is 12x and SDDS at 8x compression..

Sony really did have something there, but where the track is at on the film itself and how the processor processes the optical track into mono since it has to bypass the other default processor in the rack is what really make it a sore subject to some.

Posted by Ian Parfrey (Member # 5122) on 04-25-2010, 01:56 AM:

SR.D

For practical reasons as opposed to quality.

The vast majority of prints released have, in addition to the SR analogue track, a Dolby Digital track effectively making it a defacto standard.

Here in Australia, it's almost guaranteed that there will be a DD track, whereas SDDS tracks are getting rarer and to find (playable) DTS discs with a print is a lottery at the best of times.

As for audio quality, I agree with the others here in that SDDS- to me- sounded better and more detailed than the others.

Trouble is, just because it sounds better doesn't make it my automatic choice. The support for SDDS is almost gone, and if the DTS discs are damaged or non existant, then no matter how good it sounds, you aint getting no digital audio.

Posted by Manny Montes (Member # 5639) on 04-25-2010, 03:06 AM:

I like the way SDDS sounds, but I've seen too many prints where the SDDS track is either non-existant or damaged and drops out.

So i'd probably say:
#1. DTS
#2. SR.D
#3. SDDS

But if every print had SDDS from now on, and every theater did "film done right" it would be
#1. SDDS
#2. DTS
#3. SR.D

Posted by Peter Castle (Member # 1997) on 04-25-2010, 03:45 AM:

quote: Monte L Fullmer
Sony really did have something there, but where the track is at on the film itself and how the processor processes the optical track into mono since it has to bypass the other default processor in the rack is what really make it a sore subject to some.

In our SDDS setup, we had Dolby Digital and DTS backup so that, automatically, an SDDS failure reverted to another digital - the times that happened can be counted on the fingers of one foot.

Posted by Joe Redifer (Member # 3) on 04-25-2010, 03:46 AM:

I must have never heard a properly calibrated SDDS auditorium. We had the first SDDS installed in all of Colorado (the best state in the union) at the UA Greenwood Plaza 12, auditorium #9 (one of our 3 70mm capable auditoriums). The Sony techs were there and everything. Coincidentally, this was my first day of employment at the theater (fellow forum member Ian Price hired me). SDDS sounded good, yes. But to me Dolby Digital always seemed to have a bit more punch. SDDS sounded too "boomy". Not as in great subs or whatnot, but the upper bass frequencies, maybe 100Hz and a bit higher... too boomy. Other frequencies sound hollow either as a result of the boomy lower frequencies or something else. But this was back in the time when prints rarely had more than one digital format, so it could have been the individual mixes on the movies. SDDS was also installed in most other UA complexes that I opened in the metro Denver area and those theaters never, ever impressed me with their sound. DTS was also installed in these theaters, but never Dolby Digital except for the big house at the Continental (where it is rarely used). DTS always sounded the least good, even though my first real experience with DTS was at the Greenwood Plaza watching Jurassic Park during its opening weekend. I was blown away at that mix, but no other has ever sounded that good. But I am sure the DTS unit was set up for that specific auditorium. This was long before the 300mv thing came to pass and we would move our units around with wild abandon, never resetting the levels because we were idiots.

SDDS always seemed to be the most problematic to me. The edges of the film where SDDS lives get a shit-ton of wear. It rides on the rollers, rubs in the gate, etc. They touch everything. Unfortunately the SDDS processor did not let you know what it was doing. It just had a bunch of little VU meters that were bouncing to and fro or not. Dolby Digital seems very robust, even on older prints. I've had generously used prints read 2s and 3s. Granted, I've had new prints read 8s. DTS is just stupid because it only has to read a simple timecode that is relatively large, but often it has issues even doing that. The DTS reader is not a piece of precision electronics, that's for sure.

Posted by Catalin Balaceanu (Member # 3712) on 04-25-2010, 03:58 AM:

I don't get it! A while ago most of the people here were sh***ing on SDDS big time. Even in the reviews section it got a lousy F score. Now it became the #1 choice. How come? Am I missing something? Is it a matter of DFP-2000 against DFP-3000?
Thanks

Catalin

Posted by Demetris Thoupis (Member # 833) on 04-25-2010, 05:05 AM:

It's a US thing! They can never make up their minds [Big Grin]

. I have not heard SDDS nor have I installed but from DD and DTS I prefer 100% more DTS. I did an upgrade to a theater a few months ago with the XD20 unit for the opening of 2012 and I have to tell you I was very amazed by how clear and crisp everything sounded and the subs and everything. I have not heard great mixes on DD.
Demetris

Posted by Steve Guttag (Member # 268) on 04-25-2010, 06:54 AM:

I believe you will never find a contradiction on my statements regarding the three digitals for film. My statements are also based on several (and different) listeners that did not know which digital was playing at the time...just what they (or I) felt sounded best.

And Monte..

quote: Monte L Fullmer
Sony really did have something there, but where the track is at on the film itself and how the processor processes the optical track into mono since it has to bypass the other default processor in the rack is what really make it a sore subject to some.

What are you babbling about? SDDS did not have a "mono" track nor used an "optical mono" or whatever you are referring to. The analog track was the same analog track for everyone...typically SVA and often in Dolby-SR (in the early days and always in SR in later days).

As for the DCM (Digital Concealment Mode)...you may be thinking it is mono but that isn't even accurate. First off, the Center and Subwoofer tracks are 100% backed up and redundant on both sides of the film. When one of the sides of the film became damaged, it is true there was a "prime" version of the that side recorded in a low-bit-rate on the other (good) side. It was more sophisticated than merely a mono track since the "prime" track did have level information in it so the audio would play that the approximate level for each channel (less data needed to record on track with three low-precision levels for the three potential channels to approximate the original). This worked quite well, so long as it was not in a constant state of failure. It is like a matte painting...they will fool you...so long as they are not exposed long enough to allow you to notice the lack of detail. If the prime track is on for a second or two, almost nobody notices it (far fewer than will notice an analog reversion like with Dolby). DTS' ability to free-wheel in the absence of valid time code for several seconds has all others beat, for sure.

If SDDS has issues with both sides, it too will drop to analog...what it calls ACM (analog concealment mode).

Both SDDS and Dolby don't have perfect algorithms for when to go to analog. SDDS refuses unless both sides have issues. When in fact, they should drop if one side has enough issues over a length of time. As I said, DCM works very well, if you don't get exposed to it long enough for your ears to notice the problem. Dolby tries to hang on to a failing track much longer than it should...many have heard the "underwater sound" of a Dolby track in near failure. Dolby does, however, once it drops to analog, ensure that the track is playable before coming back to digital and the more issues it finds, the longer it must prove itself before returning to digital. Another Dolby flaw is that when it knows it is going to revert, it doesn't drop fast enough...it waits until the last bit leaves the station before dropping to analog. This is why the Cat 410 came out for the CP65 (and CP55) to shorten the debounce time on the Cat 443. In truth, all they needed to do was drop to analog sooner...nobody would care that it was in digital audio for that extra fraction of a second.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 04-25-2010, 09:26 AM:

Actually there is no reason not to use the Sony 3000s. All of them in this area still run perfectly. Problem is very few techs know how to use a laptop to set video gain on the 3000 penthouse. ONce you log on it's actually automatic! I've also never changed any LEDs in them.

quote: Demetris Thoupis
I have not heard great mixes on DD

I concur with that Demetris! I have not either... on any of the digital formats for that matter. I have actually not heard good mixes since 6 track 70mm vanished from theaters the world over. There have however been quite a number of really good analog SR mixes that I have heard over the years. You sit there and say to your self... this isn't the optical track I'm listening to! But it is...

Mark

Posted by Sean McKinnon (Member # 612) on 04-25-2010, 09:38 AM:

My list puts SR*D on top only because if reliability issues with SDDS tracks/un maintained 2000 series readers. However I do enjoy the sound quality of SDDS when properly tuned and a good track is run. I really like the Dolby system for its reliability and simplicity of operation. The DCP-D2000 unit was difficult for a lot of operators to use with it's independant volume control (measured in db unlike the standard dolby faders)and that bypass button. So many times someone would put a DCP-D2000 into bypass because of a bad track and no one would ever take it out! The operator would think they were running in digital when they were not. The DA-10/20 had no seperate volume control and had no bypass button because it was upstream of the cinema processor which is a design I prefer. The dolby readers are also in my opinion easier to maintain and once set (at least with a penthouse) almost never ever need to be touched (except maybe LED intensity once in a great while) I do not like DTS because it requires disks to be shipped, inserted, and moved with prints which often does not happen in this imperfect world. So...

1. CDS (Just Joking!)
no really...

1. SR*D (Dolby Digital)
2. SDDS
3. DTS

Posted by Steve Guttag (Member # 268) on 04-25-2010, 10:45 AM:

In truth...ALL of our SDDS systems are running, more or less, reliably. This includes the 2000, 2500 and 3000s. They are now at least as reliable as other brands of processors.

As for the 2000 series reader...with the current LEDs (which are still available from Sony)...their life is as long as the 3000 series...which, as Mark says...never seem to need changing.

The biggest wear item on the SDDS readers are definitely their sprockets.

Steve

Posted by Stephen Furley (Member # 1277) on 04-25-2010, 12:45 PM:

I was surprised to hear SDDS being so popular. When I heard it I didn't think it sounded as good as the others, but I've only ever heard it once, soon after it was introduced, one film, in one theatre, so maybe I dodn't hear it at it's best; I can't say. I've heard Tony Cutts at Pictureville speak well of it.

I've actually not heard any of the digital film sound systems very often, SR-D probably about six times, and DTS twice on new films, plus several 70mm re-releases, mainly at Bradford.

The two cinemas which I use most often do not have digital sound for film, though they do also have digital projection, which obviously has digital sound. The National Film Theatre has SR-D and DTS, but almost all of the films I see there do not have digital tracks, and the majority are mono.

I'm also not the best person to judge sound systems; at my age my hearing is obviously dropping off at the top end, and for some reason, I don't know why, I have difficulty hearing direction in sound; I can never tell which 'phone is ringing at work.

If we were to include two more formats, magnetic on 70mm and CDS, how do people feel they compare to the other three? I never heard CDS.

Unless they start to provide downloads of the CD images I think DTS is too problematical for other than first run theatres. As for the other two, I wish Dolby and Sony had got together and worked to develop a single system, taking the best from both. When I was projecting I saw few prints, maybe 5%, which had a SDDS track on them.

Posted by Joe Redifer (Member # 3) on 04-25-2010, 01:44 PM:

So when the SDDS LEDs die, what are you going to do? Wasn't this a big problem with the 2000 series?

Posted by Steve Guttag (Member # 268) on 04-25-2010, 02:07 PM:

I wouldn't characterize SDDS as "popular" except in the sense that those that have done some fair blind testing usually have it coming out on top, acoustically. SDDS remains the most prone to track damage though I'm not having near the problem with systems reading tracks as I did in its heyday.

As for SDDS LEDs...they are still available directly from Sony (as stated above). At least Sony's LEDs can be sourced from other places if one wants to change them all, themselves and try to get them all into alignment. Dolby's LED is a bit more single sourced though others have offered alternatives, for a brief period.

Steve

Posted by Joe Redifer (Member # 3) on 04-25-2010, 02:25 PM:

quote: Steve Guttag
as stated above

Missed that.

Posted by Louis Bornwasser (Member # 3063) on 04-25-2010, 02:27 PM:

sdds is the least-like-the-master, but can solve a problem or two in a big house with bad acoustics.

DD is second in a big house, but first in normal houses. dts being last.

SR analog is surprising like DD except for surrounds.

The sdds has processing on board that gives a remix to all audio. You can't bypass it.

dts has always sounded "wooden" to me especailly at higher levels. Look up ATRAC bit reduction and it will make sense. Louis

Posted by Monte L Fullmer (Member # 2797) on 04-25-2010, 04:44 PM:

quote: Steve Guttag
If SDDS has issues with both sides, it too will drop to analog...what it calls ACM (analog concealment mode).

..this would be then, the "mono" that was described by our SDDS installer back in 1997. For it was a year later, that these SDDS installs were taken out due to the major problems that these units were experiencing and CAT-701's were installed in their place - a subsitute for the default basement SRD readers.

..and that was the last time I dealt with SDDS.

-Monte

Posted by Steve Guttag (Member # 268) on 04-25-2010, 04:56 PM:

Yeah...but that wasn't Mono...it was SVA just as with any other film.

Posted by Joe Redifer (Member # 3) on 04-25-2010, 05:08 PM:

quote: Louis Bornwasser
dts has always sounded "wooden" to me especailly at higher levels. Look up ATRAC bit reduction and it will make sense.

It probably won't make too much sense as ATRAC is the compression scheme of MiniDisc, not DTS. ATRAC is also used on SDDS, but SDDS is not as awesome as MiniDisc. DTS uses a compression scheme called MPX-1000 or something like that. Dolby Digital uses AC3.

I refuse to refer to Dolby Digital as SR-D. First of all, it just sounds stupid and not very impressive. Secondly, SR has nothing to do with Dolby Digital except for the fact that the backup optical tracks are always SR on a Dolby Digital print. I do not like how Dolby is referring to their digital projection line of equipment and 3D stuffs as "Dolby Digital". Maybe Dolby should just rename themselves "Dolby Digital". I could see it now:

"Hey Ted, watcha got runnin' the sound there in that budget cinema of yours?"

"Well Bill, I got me one of them Dolby Digital CP55's and it can play not only the left, but the right channel as well!"

"Well fuck me sideways, that's crazy awesome, Ted!"

"I know!"

Posted by Marin Zorica (Member # 1716) on 04-25-2010, 05:14 PM:

You all know I'm fan of SDDS, and to Catalin and Demetris, please come here to her some sound [Big Grin]

Now, I've worked with 2000 and 3000 systems both performing very well, indeed before some couple of weeks I was at friends cinema, we did realign complete CAT700 reader, performing very well, that day some bad print came, normally SRD did drop out often, but SDDS did stay all the time. Now to forward to LED problem, that same SDDS is all ready 2yeard or so working without problems, LED's aren't from sony, but some I found on local store and they are pervertedly cheap, but after I did change them all one by one and align level and bit tweak them it works till now...so that led is not so big problem at all, not to mention there are some even better led available! Same thing on one other print with SDDS 3000 system, print is dealdy demaged, but SDDS don't drop out, as for 3000 series reader LED, you probably don't even need to change them! Why? Well....somebody clever did think to use normal "bright" led, but on normal conditions and it can last forewer, like on DVD player power button [Big Grin]

, but because of that they made perfectly good electronic hardware and even better decode and error correction algorithm. Dolby isn't bad at all, but is most bad in sound, normally due to big compression, as for DTS, they are good, even I newer loved some older hardware with PC supply. As dolby don't have either much better power supply, sony 3000 series has only 5V SMPS and all other power is made from internal DC/DC converters which are one or more per board, and to be perfectly quiet, 6 input operational amplifiers on optical input has DC/DC converter, only for it self, which are used ONLY to power analog input stage!!! Also on DTS6 de coupling transformer, which is by the way great, but somebody instead of making all outputs fully balanced, did make COLD pole of transformer all together in one point, which don't have them great use of using transformers there.

Posted by Mike Blakesley (Member # 26) on 04-25-2010, 09:33 PM:

I've never heard SDDS; there's only one system in Montana that I'm aware of, at the Washoe Theatre in Anaconda.

We used to have DTS and now have Dolby Digital. I started seeing more and more instances of prints not being shipped with DTS disks, or the disks being smashed, so we decided to switch systems as part of a system upgrade. There was a noticeable improvement of sound quality when we made the switch, but I'm sure that was because we bi-amped the speakers and replaced all the amplifiers at the same time.

Posted by Brad Miller (Member # 2) on 04-25-2010, 11:38 PM:

quote: Catalin Balaceanu
I don't get it! A while ago most of the people here were sh***ing on SDDS big time. Even in the reviews section it got a lousy F score. Now it became the #1 choice. How come? Am I missing something? Is it a matter of DFP-2000 against DFP-3000?

SDDS got a bad reputation when it first came out due mostly to acetate film stocks and poor lab work. Their reader is also a bit tricky for some people to calibrate, and trust me LOTS of techs did more harm than good! Finally their internal pink noise generator being high frequency deficient really made the end resulting sound shrill and harsh, which was a major turnoff to many people.

The 2500/3000 series reader was also a nice improvement.

Posted by Monte L Fullmer (Member # 2797) on 04-26-2010, 12:23 AM:

quote: Mike Blakesley
I've never heard SDDS

In all due actuality, they all sound the same..

Posted by Sean McKinnon (Member # 612) on 04-26-2010, 11:38 AM:

I havent read the paper on SR in a long time but I beleive SR is both a recording technology and a playback technology so it's possible that a dolby digital track is recorded using the Spectral Recording process then converted to a Digital Track making it a Digital Spectral Recording or... (Wait fot it) SR*D. This is all speculation on my part as I don't really know but it seems to make sense to me.

Posted by Scott Norwood (Member # 30) on 04-26-2010, 12:02 PM:

SR (like A) is noise reduction. Like Dolby B and C on cassette tapes. You run the signal through an encoder when recording, then through a decoder when playing it back. It only really works right when the levels are set properly (hence, cat. 69T), but gives passable results when played back through a mono system as well. It also plays back acceptably well with A-type decoders.

Dolby SR noise reduction is used for music recording as well as film, and the outboard encoder/decoder boxes use the same cat. 300/350 cards as the cinema processors (or cat. 280s in the older units).

The idea behind most noise reduction schemes is that certain frequencies are boosted in the recording process and then cut in the playback process. Noise reduction does not really apply to digital recording, since it solves a problem (background noise) which does not exist with digital media.

Presumably the "SR" in "SRD" refers to the fact that prints with SRD tracks (almost) always have SR optical tracks as well. Plus, it is easier than saying or typing "Dolby Stereo Digital" or "format 10."

As for digital playback, I have not noticed a huge difference among the systems, and dislike dropouts to optical. As such, I don't like SDDS because it tends to drop out during playback. DTS seems to be the most reliable, as long as the disks arrive. But SRD wins for having the sound on the film.

Posted by Joe Redifer (Member # 3) on 04-26-2010, 02:25 PM:

quote: Scott Norwood
prints with SRD tracks (almost) always have SR optical tracks as well.

Anyone have a list of the Dolby Digital prints which have an A-Type or mono backup? [Smile]

Posted by Adam Martin (Member # 641) on 04-26-2010, 04:23 PM:

Is it format 10 because it's digital? [Razz]

Posted by Bobby Henderson (Member # 840) on 04-26-2010, 06:23 PM:

I liked DTS, especially during the 1990s when it was clearly the more reliable system. Dropouts to analog are distracting. Dolby Digital grew more reliable as its film readers improved. Now those lossy compressed formats are becoming irrelevant as digital cinema brings uncompressed linear PCM into more theaters.

Despite the growing use of uncompressed PCM audio in theaters, I don't think digital surround equipped movie theaters sound as good on average as they did back in the early 1990s. I don't think the movie theater companies care as much about sound with stadium seating, digital projection and digital 3D being the newer gimmicks to sell.

Posted by Sean McKinnon (Member # 612) on 04-27-2010, 09:09 AM:

I think they fell that they can save money by under spec'ing speaker systems, amps, proper acoustical construction as long as it says "Digital" on the door. Older houses were built to a higher standard to get the best out of the analog systems of the day so an upgrade to digital could sound better than a new install in some cases.

Posted by Jack Ondracek (Member # 1466) on 04-27-2010, 10:40 AM:

I hate to dash water on this, but the discussion seems to be going in the same direction that every other sound comparision chat has since digital was first rolled out.

Seems to me that, to the vast majority of people, the difference is so minute as to be nearly undetectable. Most of the people who could pick up a difference would only be able to do so in an a/b comparison in the same auditorium. Just the differences between auditoriums would be enough to throw off a reasonable evaluation.

Years ago, I got letters from a couple of people who were fairly well known for their "ears". They complimented me on the quality of the digital sound systems we'd installed in the 4-plex we'd recently reopened. Thing was, we didn't have digital on any of our screens... just regular old SR, adjusted by someone who really knew his stuff back then.

At our drive-in, I have 2 DTS screens and one SR-D. It wound up that way because that was the equipment we had at the time. All have had their issues. The Dolby has had a power supply and a couple of cards replaced. It became much more reliable when I updated the reader. Now, it plays pretty much everything.

In my DTS players, I've replaced one power supply and a couple of drives. Aside from occasional alignment issues on the reader (I've busted warranty and adjusted the "hidden" screw), they work as well as the Dolby.

My only issues with DTS are the need to change disks for each show (we're double feature) and whether we have disks at all... though the latter is not a frequent problem.

As for sound quality, a drive-in with everything mixed down to 2 channels, then processed, pre-emphasized and fed into an FM transmitter is probably not a great test site. When moving prints around, there are times I think each has its better day.

Posted by Sean McKinnon (Member # 612) on 04-27-2010, 03:36 PM:

I am suprised you even bother with digital at a drive in instead of just sending lt and rt. How do you mix down the channels into 2? Do you have each channel going into a mixer in put panned for left right or center? How do you have the surrounds/LFE set?

Posted by Bobby Henderson (Member # 840) on 04-27-2010, 04:13 PM:

It's really a shame the movie industry and auto industry haven't made any effort to work together on digital surround sound standards in vehicles.

I realize some vehicles do have Dolby Digital 5.1 surround capability for DVD playback. Unfortunately, consumer Dolby Digital decoders cannot decode the AC3 format used on 35mm film prints. That makes it impossible for a car to play the DD 5.1 bit stream being processed in the drive-in theater's projection booth. With a few changes to the car's decoder and radio, a drive-in could broadcast the raw DD 5.1 signal via FM or AM and cars that are equipped could play the signal properly.

With so few drive-in theaters it's easy to see no effort has been made to address this issue. However, I think if the issue was addressed it could actually help drive-in theaters. You control the volume in your own car. Some dude in another vehicle isn't distracting you with his cellular phone abuse. If the back of your seat is getting kicked you just tell your kid to go play in the playground under the screen.

Posted by Aaron Garman (Member # 1653) on 04-27-2010, 05:37 PM:

That's a wild idea Bobby. I could, however, see some people abusing it by blasting there system when other folks have a measly sound system.

It's been far too long since I visited our drive in.

AJG

Posted by Marin Zorica (Member # 1716) on 04-27-2010, 06:28 PM:

If we stick to opinion that "most people won't nottice" what sound we have and etc, than we could stay in MONO forewer....

Posted by Steve Guttag (Member # 268) on 04-27-2010, 08:33 PM:

As for Drive-Ins...the key is to broadcast on two frequencies...one pair for Front, and one for Rear...then mix Center into Left and right. Tell people to bring a boom-box and set it on the rear deck of the car and let that be the surround channel and the car's radio, with the fader set to just the front speakers be "stage" channels.

As to determining the digital sounds...I've been pretty accurate picking off one of the digitals without first seeing the booth. I find that particular digital less pleasing and having a characteristic sound to it.

Steve

Posted by Lyle Romer (Member # 1266) on 04-28-2010, 12:15 AM:

quote: Joe Redifer
It probably won't make too much sense as ATRAC is the compression scheme of MiniDisc, not DTS. ATRAC is also used on SDDS, but SDDS is not as awesome as MiniDisc. DTS uses a compression scheme called MPX-1000 or something like that. Dolby Digital uses AC3.

DTS compression is APTX100 compression at 44.1 kHz. As far as I know, both Dolby SRD and SDDS used 48 kHz sampling frequency. Also, I'm pretty sure that DTS is 16 bit while Dolby and SDDS are at least 18 bit (it might be 20 bit, I can't remember and it's too late to research). Even though the compression ratios are much higher (especially SRD) they started with more data in the first place. The transform CODECS (used in both AC-3 and ATRAC) save a lot of bandwith simply by storing the date in the frequency domain instead of the time domain before anything is "compressed" in the first place.

The interesting thing about the ATRAC compression that SDDS uses is that Sony had to license technology from Dolby because ATRAC was very similar to Dolby AC-2 compresson. I think that the biggest difference between ATRAC and AC-3 is that ATRAC compresses each channel individually while AC-3 shares the bandwidth and uses inter channel psychoacoustic coding and bit sharing to add efficiency.

Dolby AC-3 is still very important in bandwidth limited applications like HDTV broadcasts. It is simply amazing that using 1980's research and early 1990's technology Dolby was able to encode 5.1 channels of professional quality digital audio at 320 kbps and have it sound as close to uncompressed audio as it does. 5 channels of 18 bit, 48 kHz digital audio uncompressed is over 4 Mbps.

I agree that when I used to frequent a GCC that no longer exists that had 2 THX houses and rolling digital carts, SDDS on a good print sounded the best with Dolby Digital being a close second. The Lion King in SRD was an incredible audio experience in that theatre.

Posted by Joe Redifer (Member # 3) on 04-28-2010, 01:19 AM:

I'm pretty sure both SDDS and Dolby Digital are 16-bit.

Posted by Lyle Romer (Member # 1266) on 04-28-2010, 09:39 AM:

Based upon some quick research I did this morning, SDDS is 44.1 kHz sample 20 bit audio.

SRD can do either 44.1 or 48 kHz but I remember from long ago that it seems 48 kHz was used. For resolution, according to the manual either 16 or 18 bit DACs could be used in the DA-20 (and it had future support for 20 bit). The manual says that the transform decoded data is accurate to about 20 bit resolution. Again, from my long ago memory I'm pretty sure that the DA-20 was mostly shipped with 18 bit DACs. I remember this from researching DTS vs. SRD back in the day.

Posted by Sean McKinnon (Member # 612) on 04-28-2010, 11:35 AM:

Bobby,

How would they convert a video signal of SR*D information into an audio signal that could be sent over FM radio and decoded by a car's receiver? If the theatrical version of SR*D was like SPiDF or AES then I could see it working I don't see how they could use the signal from the reader's CCD unless they converted it to analog audio and then re-encoded it into SpiDF or EAS?

Posted by Lyle Romer (Member # 1266) on 04-28-2010, 11:43 AM:

I don't think Bobby meant to broadcast the video signal off the film. I think he meant to broadcast the AC-3 bitstream as it is sent to the AC-3 decoder after the video signal has been error corrected and turned into an AC-3 stream.

Posted by Joe Redifer (Member # 3) on 04-28-2010, 11:48 AM:

So what happens when the AC3 drops out?

Posted by Scott Norwood (Member # 30) on 04-28-2010, 12:13 PM:

So, um, exactly how many drive-ins have sound systems of high enough quality to justify a fancy radio with decoding capability? Most seem to have FM stereo now, but I've not seen or heard of any other than Jack's that have digital sound.

I think that the idea of a car radio with surround decoding is a neat idea for those of us who enjoy drive-ins, but we will never see it as a factory-installed item. It won't sell one more vehicle, and the market is so limited that it wouldn't be worthwhile, anyway. Most people just want to listen to the news or background music, and few will pay for anything more than an AM/FM stereo radio with CD player.

I do kind of like the surround-channels-on-a-separate frequency idea, with a boom box placed behind the rear seat. It would be tough to get the levels right, though. And it doesn't support EX.

Posted by Jack Ondracek (Member # 1466) on 04-28-2010, 12:59 PM:

quote: Sean McKinnon
I am suprised you even bother with digital at a drive in instead of just sending lt and rt. How do you mix down the channels into 2? Do you have each channel going into a mixer in put panned for left right or center? How do you have the surrounds/LFE set?

Like I was saying, with nothing to compare it to, SR would be more than adequate at a drive-in. However, there are differences that, like many of you, I can hear... enough that I feel I'm providing a better product.

Our digital boxes and red readers feed CP-65s here.

Yes, we use mixers... active ones, to isolate the channels. Left channel & left surrounds are panned left, right channel and right surrounds are panned right, center and subs are not panned... though I'm finding that use of the sub channel is questionable.

We feed the output of the mixer into a switcher and a broadcast automation system, allowing me to route the audio directly to the processor or through the automation for programming purposes. From there, the audio feeds through a multiband processor, to reduce dynamics (pretty much need to do that in cars), and then to a (very) low power Broadcast Warehouse transmitter.

The switcher allows me to bypass the automation and run the sound without most of the gizmoes... both for reliability and backup purposes. That would also make it easier for someone else to run the booth, should that become necessary.

quote: Scott Norwood
So, um, exactly how many drive-ins have sound systems of high enough quality to justify a fancy radio with decoding capability? Most seem to have FM stereo now, but I've not seen or heard of any other than Jack's that have digital sound.

There are a few, though I'd have to spend some time to come up with a real number.

In addition to my place, I know that the Transit Drive-In has at least one screen on SR-D. Kansas City's Boulevard Drive-In claims to be the first (could be). I've seen DTS players in the booth pictures of a few more, but the names don't come to mind offhand. Many of the recent startups (yes, there have been a few of them!) have a good chance at decent sound, since the usually aren't adapting leftover speaker systems.

Unfortunately, I suspect there are still more drive-ins that feed undecoded audio through their systems than not. The FM systems that market to drive-ins, such as the Ramsey, Skymaster and Jack Roe transmitters, have no NR decoding. The Jack Roe website actually promotes this fact as an advantage, suggesting less circuitry is a good thing. I know of one or two that have "sound systems by Radio Shack", and at least one that's still running their "wall of Motiograph" amplifiers, taking a tap to feed their FM box.

In practice, using the undecoded audio sort-of addresses the dynamics issue. However, the reasons you wouldn't want to do that at an indoor house also apply at the drive-in.

More recently, Smart adapted one of their processors for drive-in use. It's much better than nothing at all, but I found the CP-65 to be more stable and natural-sounding out here. I think a couple of drive-ins are using the same boxes, but I doubt any of them were purchased new for the purpose.

There might be some potential in being able to send a digital stream to a car. However, the variables make benefits dubious. Hearing real surrounds would be cool. On the other hand, many of my customers watch the show from the back of their cars/trucks/SUVs. In those cases the stereo field is reversed as it is. Adding surrounds would really enhance that effect.

Finally, my opinion is that there's a real need to use some kind of processor to reduce dynamics and manage the effects of the FM preemphasis curve. In a sense, adding digital, or using real NR decoding on your optical fixes some issues, but creates others. Practically speaking, with FM you have about a 40dB window to work with. This is far more than anyone expects in an automotive setting, but less than is offered by a decoded or digital sound system. Without processing, a range that you'd find acceptable in an auditorium would have a car user constantly adjusting his volume control. Once adjusted for normal dialog, a minor explosion would put the radio into clipping pretty fast. In come cars, you could damage stuff.

All of this, plus the fact that each car represents its own unequalized auditorium, with no ideal seating placement, really makes it impossible to do much more than "make it sound good" at a drive-in. With no standards to define the term, those of us who pay some attention to our sound, basically "do the best we can", and rely on the few comments we get from our patrons to gauge how well we do.

Posted by Bobby Henderson (Member # 840) on 04-28-2010, 01:20 PM:

The problem with drive-in theaters and 5.1 digital in-car surround is a chicken vs. egg scenario. I think the concept is a great idea. It would be easy to implement if movie tech companies and consumer electronics companies cooperated together to make it happen. Lots of vehicles, SUV types in particular, have featured 5.1 surround capability for years already. With some minor modification that capability could be adapted to drive-in theaters and various radio broadcast applications. Let's also remember HD Digital Radio sucks it pretty badly, so there's obviously an opportunity available for Dolby to do something.

Drive-in theaters are a tiny niche market of the movie theater industry. Considering how so many audience members are stupidly rude, hopelessly obsessed with their phones and seemingly incapable of behaving properly in a group setting I think drive-ins could stage something of a comeback. The drive-in theater operator could use the negative points of watching movies indoors as a very compelling marketing tool. Right now audiences are the very worst thing about going to the movies BY FAR. You're at least a little insulated from the usual nonsense when you see a movie at a drive-in theater. Then there's the nostalgia angle. It would be a big plus if in-car DD 5.1 was thrown in as a bonus provided you have a car stereo able to receive and decode the signal -that's where companies like Dolby and various car stereo companies have to work together.

quote: Scott Norwood
So, um, exactly how many drive-ins have sound systems of high enough quality to justify a fancy radio with decoding capability?

Hardly any because no one has made any effort to improve the situation.

The thing I would like to see only involves broadcasting the AC-3 bit stream from the 35mm print over an AM or FM carrier signal. The viewer's car stereo would do the actual decoding and audio playback work.

quote: Joe Redifer
So what happens when the AC3 drops out?

I thought Dolby Digital on 35mm worked perfectly now -at least that's how it seems to be characterized. In the event of a serious soundtrack failure the viewer obviously would tune his radio to an analog stereo version of the sound track.

Posted by Joe Redifer (Member # 3) on 04-28-2010, 01:33 PM:

Yes, Bobby, but if you are broadcasting a digital AC3 stream to cars and the digital on film drops out just for a second or two which is usually the case when it drops out, there would be abrupt silence. And with the latest fad of putting copy protection in the analog track with forced digital drop outs on loud scenes, it would get annoying very quickly.

The problem with surround sound via extra boom-box is that most cars have speakers all over and they'd have to adjust the balance so that only the front speakers play. Most people don't like fidgeting with their radio settings once they get them set just the way they like them.

Posted by Tony Bandiera Jr (Member # 2365) on 04-28-2010, 04:57 PM:

I say screw it, let's go back to the early days with giant Altec speaker towers flanking the screen!!

I have been told they worked surprisingly well even though it tended to piss off the neighbors.

Posted by Richard Fowler (Member # 893) on 04-28-2010, 05:46 PM:

So how would you thread up your soundhead to compensate for the 200 - 400 foot sound delay from those Altec speakers [Razz]

Posted by Louis Bornwasser (Member # 3063) on 04-28-2010, 07:48 PM:

No lower loop at all!! [Big Grin]

Our standard drive in system is all analog: Red LED; Smart Mod 2b-dit; Ashly compressor; Broadcast Warehouse 5 watter (easier to turn down.) Mount the antenna near the baseboard to kill range. Louis

Posted by Jack Ondracek (Member # 1466) on 04-28-2010, 10:34 PM:

quote: Louis Bornwasser
Our standard drive in system is all analog: Red LED; Smart Mod 2b-dit; Ashly compressor; Broadcast Warehouse 5 watter (easier to turn down.) Mount the antenna near the baseboard to kill range. Louis

That'll work!... Takes up less rack space than my setup, too.. [Big Grin]

Only problem is the status of the Smart box. Thought they'd be out of stock now.

Posted by Marin Zorica (Member # 1716) on 04-29-2010, 02:50 AM:

I do have one open air here, we are using only left and right channel, first because they have only two speaker, and second because they need to take them in and out for every show. As I do have sony DFP-3000 I use monitor output, and there I can mix whatever channels I want to hear, so for LEFT speaker mixer are Left, Left Surround, Center and Sub, and for RIGHT there are Right, Right Surround, Center and Sub, it's good trick to have that inside mixed in processor, so saving some money for mixer and space in rack [Big Grin]

Posted by Bill Duelly (Member # 3612) on 04-29-2010, 08:23 AM:

I have been very impressed with the dynamic range of the SDDS 3000 I have recently setup, but the sporadic drops are really getting annoying. I'm trying to find out any rhyme or reason to that activity. I run a print that has quite a bit of wear from 2001 and it plays flawlessly, but some gently used prints from 1997 seem to drop at will ( what seems consistant is when it gets near a lab splice, it starts to get weird. That I attribute to light leak problems in printing). Also, I run off of reels, not a platter if that helps in figuring out..
Were there a lot of problems with SDDS tracks in the late 1990's? I keep hearing that the 3000 system was the best one. Maybe I am missing something in setup?

Posted by Marin Zorica (Member # 1716) on 04-29-2010, 12:01 PM:

Bill, first you need to check are reader is clean and so, but you probably did that....second as you run changeover, is film tension is constant or is woofeling near rader?

I bet you know all that, now it would be good to calibrate reader CCD gain, it's simple by connecting reader to PC (RS232 is behind cover near reader cable). I have one print from 2004, print is very damaged since I did use it to set my spool system while developing some things, it has many splices, tearing and so....but SDDS don't drop at all on it.

If you need advice how to align reader let us know, or search because I think I wrote that somewhere here already.

Posted by Warren Dewey (Member # 3609) on 04-29-2010, 12:08 PM:

Back when I used to mix movies, we a-b-c-d-e'd SR vs SRD vs SDDS vs DTS vs the original 96Khz 24 bit surround mixes on an independent show that I thought sounded pretty good. I heard it in a theater recently and it still sounds good.

This was all on the same mix stage, and about 6 people pretty much agreed on this ranking. Print problems like wear and dropouts were not considered of course:

1. Original mix
2. DTS - very "open" and clean, close to original
3. SDDS - slightly squashed and nonlinear dynamics
4. SRD - very compressed and oddly close to optical in character
5. optical (SR)- expected limited bandwidth and crosstalk issues

Posted by Steve Guttag (Member # 268) on 04-29-2010, 12:14 PM:

Did you do it blind or did you know what you were listening to?

Steve

Posted by Sean McKinnon (Member # 612) on 04-29-2010, 04:01 PM:

I guess my question was how would you tap off the Ac-3 bit stream from a da-20, cp500, or cp650?

Posted by Warren Dewey (Member # 3609) on 04-30-2010, 12:17 AM:

It wasn't totally blind. Two of us spent quite a while matching levels. This is really important. Even tiny differences in level can be perceived as qualitative differences.

Then one person would start rotating through the different outputs, and take notes on the comments. We took turns being the switcher. After a while we all started to zero in on commonly perceived differences. It wasn't that hard to differentiate. It should be noted these were all professional sound people, accustomed to listening critically.

Posted by Marin Zorica (Member # 1716) on 05-03-2010, 10:55 AM:

quote: Warren Dewey
It wasn't totally blind. Two of us spent quite a while matching levels. This is really important. Even tiny differences in level can be perceived as qualitative differences.

This is totally true, I also do have back in broadcast field, the more "powerful" sound is, eq the more average level is raised, so that is "louder" the more people will like it, also there were some reasearch from Orban (they make broadcast processors) when people did search between station, they stay on most lauder.

Another thing considering SDDS drops out, if we use down mix to say 4 channel SDDS which is available under preset option, should we have less drops on bad print, as less channel, less information from film is needed for decode?

Posted by Steve Guttag (Member # 268) on 05-03-2010, 12:52 PM:

Interesting. Thus far (and it has been a while), your findings have not mirrored mine in several "shoot outs" with different material. In my case, the people listening did not know which format was playing. And, regardless of venue, the results tend to be consistent. That is, for those that could hear a difference and MANY did not notice any difference. These are not critically trained folks, by the most part...but a range from installers to just patrons.

There is one digital format that I can normally pick off pretty quickly and it was ranked pretty high on your list. I would not call its high-end very natural at all.

Steve

Posted by System Notices (Member # 2357) on 11-27-2011, 02:04 PM:

It has been 573 days since the last post.

Posted by Aaron Garman (Member # 1653) on 11-27-2011, 02:04 PM:

Could a lot of these differences between the formats simply be due to the person encoding a given track? I mean, who does the encoding for a given print? Is is Dolby, DTS (datasat), or Sony? Or is it done at the lab by the printer?

The same arguments came up a lot with home audio Dolby Digital and DTS back in laserdisc days, and it was hard to do a fair comparison since different people were doing each respective encode.

Having said that, I would imagine that DTS (APT-X100) is the most capable because it compresses the least from an original master. Dolby is extraordinarily efficient, but are there encoders for film prints as convoluted as their professional home ones that offers compression, mix down metadata, etc.? I know very little about SDDS other than when I saw Titanic presented in it, it blew me away.

AJG

Posted by Monte L Fullmer (Member # 2797) on 11-27-2011, 08:14 PM:

SDDS's compression was inbetween DTS and SR-D .. about 8x compression.

SDDS was an odd duck of sorts in it's digital playback methods.

Processor was self contained-completely bypassed the other processor in the rack. If the digital failed out, it would revert to it's own mono output since there were no pulse from the SDDS processor to tell the default processor to pick up the stereo optical sound if SDDS failed out.

Processor itself had a slight funky volume control where the output display was in dB, not simple graduates like the Dolby and others were we use "7" as default for sound tests and required volume settings. Thus "0.0" was the default setting so where you ran your movies at a -"2.0" for a comfortable listening. What I liked on the processor is that the front display opens up and you can see the individual frames and it would also display it's own error messages since the trackss were on the film that wore the most - you were good to have good SDDS sound for a couple of week before dropouts occur.

Reader had two pickups-the soundtrack side was the main one and the backup track on non-soundtrack side of the film. Soundtrack side was 26 frames ahead of the optical and the opposite side was 26 frames behind the optical track. The main sprocket in the middle had a driver behind it that would pulse the LED so the pixel infomation read by the readers was a steady image.

True though, the SDDS system had the opportunity to do eight channels.

Yes, when it worked, it really worked well. But after a couple of weeks running, there were so many dropouts from digital to mono that operators would soon bypass that reader (the earlier 2000 reader) to run the other digital readers in the film path string.

Posted by Aaron Garman (Member # 1653) on 11-27-2011, 08:26 PM:

We had one SDDS house when I was still projecting, and the only unreliable thing about it was prints not having a SDDS track. I did always feel that the EQ was conservative and that most films, even loud ones, were not as loud as the other houses with digital sound.

It was eventually replaced by a DA20 and boy did they do a good EQ this time. Up until the digital cinema conversion, it was probably the best sounding house in that complex.

AJG