My first thought was that "someone's not cleaning that hard junk the builds up on the trap runners (most of our projectors are Simplexes.)

But he swears that is not the case; they are cleaned fairly regularly. He's pretty good at checking this; he goes right into the booth and looks at the projectors. So while he's not sure what causes the high error rate, the projectors are being kept clean.

As far as SDDS is concerned, I think you have to replace the LEDs once a year. Not quite sure on that. SDDS is notorious for cutting in and out.

Joe is right, you should check your Dolby Digital Reader's LED video amplitude. It may be low and causing drop-outs (below 2.0V as measured on an oscilloscope at the video test points... Cat 670 card). I would recommend checking this once a year, or whenever there is a suspected problem. The video amplitude is set for 4.0 volts at the factory. If the video amplitude checks out okay, then verify the other alignment paramaters... focus, lateral and azimuth.

Of course, I wish I had some hard data to support this "impression" the district manager has regarding the units. Is there any was for a DA20 to internally log the degradation? We don't have enough PC's to leave connected to all the units to monitor!

I'm not sure how many lamp vs. LED Dolby readers we have, or even how many are basement readers. Do the LED readers stay in alignment longer than the older regular lamp type? Do you think that the (regular lamp type) should be changed more often than the manual recommends? Are basement readers still considered less reliable than the Cat 700 type?

Does SDDS really suggest changing LED once a year? The LEDs only come on (full) when the reader sprocket is turning. Does the manual say how many hours you can expet from the LEDs? Do they stay in alignment?

I know I'm being a bit vauge with my statement of our problem, but I guess I'm trying to see if this is fairly common. I guess I'm in the early "fact-gathering" stage to see if they fail more often then we know.

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SDDS was very problematic until that theatre actually got a booth manager and the LED arrays were changed and calibrted.
This was on the 200 models.
Im not sure either how long they are supposed to last because i never had to deal with them.

sony did just come out and do a reader upgrade and changed all the LEDs so well see how long they last.

The 3000 models have one LED that ive been told is never supposed to go bad.
These were put into the theatre i now work at and weve had problems with them not reading properly since opening day.
Also, the analog these new SDDS units produce has never been satisfactoy in my opinion.

Actually, that's what started this. I asked the DM why we don't just buy all SR-D. (It's not that I don't like DTS, I'm just thinking of easier maintaince; and while some films do not come out in DTS, almost everyone uses SR-D.)

James, I disagree with you about the DFP-3000. I have found the new reader to be far more reliable than the 2000's. If you are having problems with digital tracking, try running the R3000 auto-align program from a laptop computer. This tech note is also available from SCPC. Perhaps the equipment installers did not do this at installation and the readers are a little bit out of alignment from shipment? Just a guess, but is definately worthwhile to give it a try.

I wouldn't say that the LED readers stay in alginment any longer than the older style halogen lamp readers. Be aware that although the hologen bulbs seem never to burn out, they absolutely will develop a permanent haze on their reflector which can severely reduce video amplitude. I recommend changing the halogen lamp when it fogs, or perhaps once a year (okay, you can maybe get two years before you notice any fogging). Basement readers can be just as reliable as penthouse readers depending on projector and use (or abuse).

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The internal eq in those units is too harsh and digitized sounding for my taste anyway and I have taken to bypassing it and utilizing the eq circuitry in the Dolby processor, which just wastes money on that part of the SDDS player that is no longer being used. However I have obtained magnificent results when wired in this manner. Why the need to offer internal eq in the first place is beyond me.

If you've got a cat700 SRD penthouse, be sure and check that power supply/molex connector. I've had a couple that would damage the lamp after a month or so running.

So far, the only SR emulation that I have found pleasing is the Dolby CP-650...none of the other analog (including Dolby's CAT222SR/A) nor digital attempts sound good to me...very harsh and non natural. So far, the CP650 has been a pleasing sounding processor for both digital and analog....I was pleasently surprised.

I have not found the SDDS processors to have the brittleness described but I have found that the SDDS pink noise as generated in the 2000 to have an HF roll off as compared to either the Cat. 85 or CE SG-1 pink noise generators...as such if the same person tunes both the SDDS and another processor, the SDDS will sound more strident.

Steve

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