Film-Tech Forum ARCHIVE: What would cause the sound to be skipping like a CD?

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Posted by Robert LaValley (Member # 4319) on 07-08-2008, 11:45 PM:

I just watched "wanted" at a local AMC theatre. I dont know what equipment they are running however I am curious what would cause the sound to sound like a skipping CD. Like it had digital noise in a way. Almost like web streamed sound? but it wasn't motorboating becuase the dialogue was very clear. Any ideas?

Posted by Joe Redifer (Member # 3) on 07-09-2008, 02:22 AM:

Two possibilities:

You so say it is AMC. AMC is known throughout the world for their wanton SDDS lovin'. The SDDS could have reverted to the backup digital track which is much worse than the main track and likely worse than the analog SR track (I don't think I have ever heard it).

Or if they are actually using Dolby Digital, it could be the Dolby Digital F-ing. When that happens it can sound clicky and jumpy (or even the quick "chirp" digital noise) even though it never reverts to analog... it just sits there and Fs. Once it Fs so many times in a certain amount of time, it will finally revert to SR until the F-ing stops. What you describe leads me to believe that this is actually the case, but AMC using Dolby Digital??? Must be a newer (7 years old or less) location.

Posted by Robert LaValley (Member # 4319) on 07-09-2008, 07:02 AM:

I believe its a new location (within the past 7 years that is). Overall they do a pretty good job in presentation there,this is really the first real problem I have experienced watching a movie there in 4 years so I think thats a pretty good ratio. Ive had cp650's F out and stay in SR for the rest of the feature after a bad reel. So once again I'm guessing since I dont know what they are running but do you know if it could revert back to digital if it finds enough "good" soundtrack after having a bad reel that would cause it to "f" out? (yeah I know that question just sounded like a who's on first routine - haha)

Posted by Sean McKinnon (Member # 612) on 07-14-2008, 05:27 PM:

They probably need to re-calibrate or replace the LED assemblies in an SDDS reader.