Part-2 http://www.dtsonline.com/dolbyrvu.pdf

Mark @ New GTS

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The building where I currently work is set up as John describes: there is one OC-48 to the building which is fed to a demux and from which POTS lines, T1 lines, etc. are run to individual offices. As a side note, this creates an interesting single-point-of-failure issue: my employer's network is multihomed with two ISPs using two T1s, but that doesn't help if some backhoe cuts the fiber to the building (which would take out voice telephones as well).

vis-a-vis T1 vs. DS1, DS1 is ANSI nomenclature, and T1 is Bellcore nomenclature, and as a practical matter, they are used 100% interchangeably by the telco community, though there's certainly a bias in the vernacular towards saying "T1." (On the flipside, at least in the IP world, DS3 is a lot more prevalent than T3.)

If you consult ANSI T1.106 (my copy is at home...; yes, it's T1.106 despite the fact that DS1 is the thing it defines), I believe you will find that it explicitly specifies the electrical (i.e. copper) interface for a DS1, specifically implying copper, and it's not until DS3s (hmm, or possibly some sub-DS3 -speed specification that is not generally used) that optical interfaces are discussed.

--jhawk

2ndly:
I agree that its time for a DVD/HD based DTS unit. I think that this unit should have n option allowing the user to playback from the HD or the DVD, that way if the HD fails, you have a backup to use while you wait for your theater circuit to send out an engineer.
I do not think that a central server is a good idea, servers can esily fail, and when they do you would loose all digital sound in your dts theatres. The only server i would trust with such a task would be a MacOSX Server or another UNIX based system.

DTS has adopted a pretty good strategy of not requiring the user to have to configure the box or make decisions very often. Probably it would be best for them to stick with that, with the box figuring out if the HD had failed by itself, but of course allowing you to override this. It's a fine line between "technician configuring the box knows best," "projectionist running the box knows best," "manufacturer of the box knows best," and "nobody on earth knows best!"

Here are some pertinent quotes:

"Most T1 service installed today is delivered via HDSL technology, which provides a T1 connection between the ILEC or CLEC and the customer."

"A well-known technology, HDSL has been in use for more than a decade as the generally accepted means for delivering T1 service."

"High bit-rate DSL (HDSL)...is used as the signaling technology in approximately 80% of T1 connections."

In any case, it's definitely not what most people mean colloquially when they say "DSL" or even "xDSL." Off to go scratch my head...

DOLBY DIGITAL is my personal favorite. It's a data-on-film format (very important, imho) and there are at least five versions of the Dolby Digital logo trailer. Dolby provides free trailers every year to every Dolby-equipped theatre (but this offer may not apply, or may vary, for those of you in North America). Moviegoers are also very familiar with the Dolby name and logo, so my hunch is that's what influences my clients most.

SDDS is also a data-on-film format. It costs about the same as Dolby Digital and it is the only one with a digital backup. It also offers up to 8 (discreet) channels, but such movies are rare. Most SDDS screens I've seen are only set up for 6 channels. AFIAK, there is only one version of the SDDS logo trailer and – way back when I worked for AMC – Sony was charging about $55 for trailers.

DTS is the cheapest to buy/install, but the discs often arrive late - I'm in The Bahamas, so we get our prints sometimes a week ahead of release (due to our separate ratings system). The DTS discs are never ready, and I always have to call to order them. Almost a decade after its introduction, there are only two versions of the DTS logo trailer. The newer "Sonic Landscape" trailer is good for use on quiet, intimate movies but I have to say I'm not that impressed with it. Also, DTS used to make you pay $90 for a set of 4 trailers (2 flat, 2 scope). However, I think they have recently stopped charging for them.

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And, hey! Let's be careful out there.

~Manny.

I've never been completely thrilled with the sound from a DFP-2000 processor, but I've got to tell ya, hook up a DFP-3000 (or a DFP-2500) THROUGH a Dolby processor (bypassing the Sony EQing) and it is DAMNED impressive! This is currently my favorite and preferred setup, at least until someone comes along with something better or I am introduced to a better existing product that I have not used. Then again I don't care for the sound of a Dolby CP-500 either.

For general cinema use though, SRD is still my number one choice because of price and availability of prints with SRD tracks, plus top notch customer service. A CP500 or CP650 simply cannot be beat as a package with those two very important points taken into account. If money was no object, I would install DFP-2500s through Dolby CP65s or CP200s, as these are extremely good and reliable, plus you've got great customer service from the Sony guys too. Unfortunately those aren't too cheap and very few theaters are willing to spend that kind of money. Dts has been my last choice for awhile now, not in terms of quality (which is very good and very reliable), but I got screwed about a year ago from dts customer service because Film-Tech is not a huge theater chain or dealer who sells hundreds of their systems and apparently us small guys are not important to dts to make good on defective equipment. I have a hard time supporting a manufacturer who works like that.

sorry to disagree on the SACD and the human ears "incapable" to hear the advantages of extended bandwith (SACD goes down to 5hz too).
First, an audiophile ear becomes much more accurate over time, even if it looses some of its sonic ability with age.
Second, the "filtering" of PCM on CD induces distorsion much sooner, or much lower should I say, than 22khz. By extending the higher bandwith, SACD ( and DVDAUDIO )pushes further that distortioned zone, allowing almost digital distorsion-free zone up to say 50khz or so.
I don't know if you have heard SACD, but it's quite a whole new world.
The authenticity of the sound is stunning, providing the room, amplifiers and speakers are able to produce these extended frequencies. And third, the humain brain-skull and body are very receptive too, not just the ears. http://interprod5.imgusa.com/son-403/technology.asp

back to dts vs dd : those two hate eachother, especially Dolby who really didn't like DTS to try to take a share on dvd: hence, this flawed "blind" test, as DTS was cutting in half ( which is just a bit lower than the cinema dts btw ) its data rate...

I used to think that the three digital formats were pretty much indistinguishable, but now I would give a slight edge to DTS over SR-D. It just sounds nicer to me, especially with music.

I tend to think of SDDS (old-style readers and processors) as being roughly equivalent to SR-D as far as sound quality, but substantially inferior as far as reliability.

Overall, SR-D is the nicest "system" for most theatres: it sounds good, it's simple, it doesn't have disks to get lost (or not be shipped), it has more titles than either SDDS or DTS (esp. many arthouse films), and, most importantly, it "just works."

DTS has some nice features (separate language disks, for example, and non-audio data like subtitles, etc., as well as 16mm and 70mm compatability), but it's primarily useful for first-run houses that play mainstream films. It would be mostly useless in an art-house (where many prints are SR-D only) or in a second-run house (where disks may not arrive with prints).

SDDS is just overpriced and the first generation of equipment was less reliable than DTS or SR-D.

If I were a theatre owner, I'd first put money into a top-notch analog system (processor, amps, speakers, acoustical treatment) and maintenance and then, if I still had cash left over, I would consider SR-D. DTS would be a good second choice, but only for a first-run non-art-house. I'd only consider SDDS as a secondary digital system and only in an 8-channel-capable house.

Having said that, I recall reading somewhere about a test that will very much discredit SR-D. What you do is encode 2 screen channels, the surrounds, and the LFE with normal cinema sound like would be found in a shoot-em-up action movie. In other words, lots going on in those 4.1 channels. But in the remaining screen channel, you encode a musical instrument, something like a sustained chord or single note from a piano. Turn off all the amps except for the channel playing the musical note and listen. You will get something pretty shockingly bad. The bit-bucket won't have anywhere close to enough bits to support the lone musical note. It will be full of artifacts. DTS and SDDS do not have this "issue".

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- dave
Look at this! His chin strap has been cut!