DTS-S (not DTS Stereo)

[David Ferguson]

In my quest to experience as many odd, outdated and legacy formats as possible, I'm now looking at DTS-S.

First, let's clarify that this isn't "DTS Stereo" (the analog track put on some original DTS prints that wasn't Dolby NR or Dolby matrix encoded) - this is "DTS-S" that I'm (currently) interested in. When DTS first was announced in 1993, cinema owners could either install the DTS-6 or the DTS-S processor. The DTS-6 was the 6 channel version, but the DTS-S was a cheaper 2 channel version, that played digital audio from 2 channel discs, that was then matrix decoded (in the standard analog way, using the theatre's existing equipment) to form the LCRS. You got the benefits of digital sound, but not discrete channels.

My limited knowledge and research on this shows that the DTS-6 and the DTS-S were basically the same machine, but with a different output card, and the DTS-S only having a single CD-ROM drive compared to the two offered in the DTS-6, as the 2 channel files were smaller. You could upgrade from a DTS-S to a DTS-6 by swapping the 6 channel card, and adding an extra CD-ROM drive. I don't think many films were offered in this format, and all owners quickly upgraded to the DTS-6.

What I'm wondering:

• Is there a manual for the DTS-S anywhere? I've never come across one.
• Does anyone have any DTS 2 channel audio discs? Originals or copies or ripped files?
• Does anyone have a DTS-S 2-channel output card lying on a shelf, in a drawer, somewhere?

[Gordon McLeod]

The manual was part of the original DTS manual to sections one for 6 track and one section for stereo
The output card just had unstuffed areas in the ones we installed.
Interestingly they recommended initially hooking up the stereo output even on the 6 track version incase one only got a stereo disk

[Pete Naples]

I always knew that as 'DTS Stereo' There were a (very) few installations in Scotland. IIRC the now replaced UCI Kinnaird Park had some. Possibly Clydebank too. I don't recall hearing it called DTS S though.

In the very distant past I did indeed upgrade some early DTS players to 6 track, I don't remember the specifics but what you have described sounds about right. I do remember the original output being connected to the CP65s so that it was decoded, I *think* it was connected to the P2 input. But what I can't remember is how it selected, as it would need to disable the NR.

Most of the people who might remember or really knew are long retired or no longer with us

[David Ferguson]

The only manual for the DTS-6 I have seen is the one in the Film-Tech warehouse, revised 1996. It doesn't have a section for DTS-S, and has comments like "NOTE: The STEREO adjustment trim pots are no longer used." so I assume it was scrubbed of all that info. If you or anyone else has an older manual that includes the DTS-S info, I would love to see it! And if you or anyone also has a photo of the DTS-S output board I'd be interested in seeing that too...

[David Ferguson]

I always knew that as 'DTS Stereo'
Most of the people who might remember or really knew are long retired or no longer with us

I could be wrong, but so far I have found that DTS Stereo refers to their 4:2:4 analogue track that DTS put on their films, that was compatible with Dolby's matrix decode. I'm not sure if they put on a A-type-compatible NR as well, or just the matrix. I know that the DTS-6 label on the bottom (at least the early ones) referred to that device as "DTS-S / DTS-6", as the unit itself could do both depending on what card was in it.

It is nice to know of a few sites that I am familiar with in Scotland! I never went to the UCI Kinnaird Park, but have been to the Odeon replacement several times.

Most of the people who might remember or really knew are long retired or no longer with us

This is what I'm concerned about - soon these formats will be totally forgotten, and I'd love them to live on a bit longer, and maybe even get a chance to hear it. Digitally recorded 4:2:4 is a bit of an odd concept, but I suppose later "came back" with Surround EX, where the Dolby SA10 unmatrixed the left and right surrounds to create the rear surround channel.

[Pete Naples]

I always understood, that DTS Stereo was a 2 track playback, from disc, sent to the processor's Lt/Rt input and decoded as if it were SVA.I always assumed the optical track was a standard 04/05.
BUT it was a very long time ago, I've dropped the odd motorbike and had children since then. All a bit of a blur to be honest.
That stuff predates anyone I still know who was with DTS, the company changed hands so many times there's no solid history left.

SA10, the less said, the better.

[Gordon McLeod]

DTS stereo was originally two channels matrixed and fed into the projector two optical preamplifier with a poor Atype emulation. The encoder was the same as used on the optical tracks for DTS stereo releases
Later ones used SR but originally it was A type
The dts 2 channel had only one codek chip on the output board and two transformers on it. The 6 track had a daughter board with 6 transformers a DB50 output connector and a ribbon cable that ran over to the same board that had the remaining codeks installed

[Marco Giustini]

I remember reading about DTS-S on my 1993 DTS-6 player. My understanding is that it was short-lived as the 1996 manual seems to confirm. Yes, there was some confusion about the DTS analogue track on a "DTS only print" and the "DTS Stereo" 2ch digital track coming from a DTS-6 player.

DTS_Stereo_1994.jpg

The DTS-S output shows "Left Total" and "Right Total" outputs so those were supposed to be processed by a matrix decoder I guess.

Very cool and I believe the idea was that a DTS-S system could be updated to DTS-6 by just adding parts.

SCR-20251007-iwyr.png

From what I see, the D420 fits two APTX100 chips so that's doing Left and Right. The add-on D421 adds three more chips for 5.1 (5.0 actually as LFE in DTS is not discrete). I'd imagine that a DTS-S would only fit the D420 and to "upgrade" one would need to add the D421. The trimpot location also matches the boards.

IMG_2244 Large.jpg

[Paul Finn]

Where is Daniel Schulz when we need him again? I sincerely hope this highly respected authority on all things DTS from the beginning, has not left the Film-Tech forums for good!

Paul Finn

[Steve Guttag]

What part is in question? DTS-S has been covered. In 1993, when all of this came out, DTS thought that the DTS-S version was going to be the dominate version (cheaper and easy to implement). They were caught off guard in that almost all were DTS-6 because it was just slightly more expensive (something like $1,000 extra but that would only bring it to something like $3,500/screen...which was a tiny fraction of what Dolby or SDDS was charging for their digital) and with Jurassic Park, the format was guaranteed a big interest.

I may have put in 1 or possibly 2 of the DTS-S systems but all were converted to DTS-6. And yes, at first, it was recommended to connect up the DTS-S outputs as well as the DTS-6 outputs but that fell by the wayside. Most cinema processors, at the time, had a means to quickly/easily take the 6-channel outputs.

The DTS-Stereo thing came later and is confusing the issue as it was, like Ultra Stereo, a Dolby alternative for Universal Studios that didn't want to pay Dolby for licensing Dolby Stereo. Jurassic Park was already well into it so it always had a Dolby analog soundtrack but future Universal titles.

[Marco Giustini]

very interesting, thanks Steve!

$1000 extra, I can understand why cinemas went for the 6ch version - though I'd imagine many cinemas failed to properly upgrade the sound system to cope with the new available dynamic, particularly on low frequencies. They probably just split the existing surrounds and happy days!

It's so cool to see that a 5ch system required 5 large APTX chips, once per channel, when today this is could probably be done by a Raspberry Pi via software!
And if memory serves the DTS-6D had a different board with 5 chips on it and an empty socket which was used for the SV version - too bad they never upgraded the system to a discrete LFE channel though I could see the benefits were not worth the hassle of upgrading all the units on the field or having a dual inventory nightmare.

[Steve Guttag]

They didn't split up the surrounds, necessarily. DTS always supported mono surrounds (as did Dolby Digital). DTS had a gazillion kludgy boards done by Mike at DTS (before Odyssey got into the game) to ensure their players could connected to ANY processor in the field. The DTS-6 had a DB50 ribbon cable that split out into the typical CP200 2x10 header plugs. That leveraged that to plug into their adapter boards to fan it out into whatever sound processor you had. If you had a CP200, you continued to use the "Stereo" cable as it had an additional kludgy board with a relay to interrupt the Subwoofer signal. The downside on that was...there was no volume control for the subwoofer. For everyone else (or if you had a CAT560 for your CP200), you could just use the "Le" line as your subwoofer feed into your processor's Aux input. But they really did go out of their way to adapt it to most every processor in the field. They also did it with relative short lead times. And, if they didn't have a board for your set up, you could use their general purpose HDR to audio output and just solder up your own audio cable to whatever "thing" you had.

[David Ferguson]

Thank you Macro for these photos. It does look like you say - that the DTS-S was upgradable just by adding the D421 board. And maybe upgrading the ROM - perhaps Steve or someone else remembers what the upgrade consisted of?

I have since managed to find myself a DTS-6 player - upgraded to the latest 1.46 ROM - and I may try and see if it can be persuaded to play a DTS-S disc. I imagine the 1.46 ROM won't allow this, but no harm in trying.

[Marco Giustini]

I'd be curious to know the outcome, David.
I have a feeling that the ROM doesn't matter much when it comes to decoding. Let us know!

If you stumble into a DTS-S disk, I'd love to get a copy too as I have a DTS-6 in my collection too.

BTW: Please remove the VARTA battery from your DTS-6 ASAP. It won't matter as I believe the BIOS defaults are already correct but those batteries WILL leak and destroy your motherboard.

[David Ferguson]

I have some DTS-6Ds with older ROMs (1.29 I think) but will try the DTS-6 with the 1.46 ROM first.

I am aware of the battery issue - the first DTS-6 I bought had a leaked battery, and the logic board was entirely destroyed. I tried to re-wire the corroded traces but it was no good, it had got under the 286 processor. This one looks ok - but I will be cutting that battery out!

Interestingly this DTS-6, as well as my previous one, both had a broken power switch. It feels much tougher, and doesn't join the contacts. I suspect something inside has warped/bent/broken. But it is interesting that 100% of the DTS-6 players I have come across have had this issue. Is it common? Anyone know of a replacement switch that is the right size?