Film-Tech Forum ARCHIVE: Sound Problems

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Posted by Erick Ojeda (Member # 216) on 01-15-2000, 08:15 PM:

Hi,

Last night I was experiencing some problems in the booth. First of all, the automation wouldn't start on our number 10 projector. I pressed the start button, and nothing happened, so I ran it manually. Second, our SDDS reader has been experiencing some dropping out. I'm not too sure if it is the reader, or poor film handling by our projectionists because other films have been doing the same thing lately, but more so with Any Given Sunday, which is running through an SDDS reader. So the audience didn't have to experience sound dropouts, I decided to bypass the reader and run analog. Now here is where the problem kicked in. I set the processor to mono, but only received sound on our booth monitor, and not in the auditourium. Then, I hit the dolby stereo button to see if that would do anything, but the sound still kept on coming through the booth monitor, and not the theater. I checked the exciter lamp, and it was on. I called my general manager up, and he wasn't sure. So, he told me to stop the projector and thread the SDDS reader. He said we were better off running it in digital. I did that, started up the projector, and still had the same problem. He kept on hitting different buttons, and finally the sound blasted in after he hit the dolby stereo digital button. At this point, sound was on in the theater, but as soon as the feature presentation hit the screen, the dropouts began. The other manager came up, and hit the mono button. This time, it worked. I was confused because I thought if I was to bypass the reader, the sound would already be mono. My question is if I wanted to run a film in analog, do I have to thread the reader and hit the mono button. I want to run some of our films in non-digital formats because we have been experiencing drop outs, and I don't want to run poor shows. Does anyone konw what could have happend, and maybe give me some advice?

Thanks,

Erick

Posted by Scott Ribbens (Member # 180) on 01-15-2000, 09:22 PM:

What model of cinema processor do you have? What automation do you have? Was there a power drop out or brown out just prior to this? If you want to run a good show in an optical format, you should be punching up 04 (Dolby Stereo) or 05 (Dolby Stereo SR) and not mono. It is possible that the control card flipped out for a little while (could really be the case if there was a brown out) as I had this happen to me once. In that case turning it to bypass and then flipping it back to normal fixed the problem. That only happened to me once on a Dolby CP-65 and only after a power brown out. The combo of the automation not working, and the processor flipping out may be related, or could just be a coincidence. As they say in the scientific community: "Just because two things happen at the same time, does not mean that they are related".

Gives us some more info on your equipment, and I'm sure that you will get a lot of suggestions as to what may be happening there. My guess is that is was a fluke (not the meter) if you have not had other problems with the automation and processor in the past and everything runs fine now.

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quote:
"More human than human" is our motto.

Scott

Posted by Erick Ojeda (Member # 216) on 01-15-2000, 10:16 PM:

I know we have Xetron Automation and dolby processors, but as to the model number I am not sure. I just started working at this theater. I did try hitting audio backup, and then hitting the mono button, but it was doing the same thing. Nothing happened until the gm came upstairs, told me to thread the SDDS reader, and then he somehow got it to work by hitting buttons. I work tomorrow night, so I will get the model numbers.

Erick

Posted by Erick Ojeda (Member # 216) on 01-15-2000, 11:11 PM:

Scott,

I had time, so I went through the picture warehouse and saw that the Mann's Colony 12 in Louisville has the same equipment we have except for the platters. The automation is Xetron Maxi 12 XPC. AS far as the processor goes, I couldn't get the model number from looking at the picture, but it does look the same.

Posted by Scott Ribbens (Member # 180) on 01-16-2000, 12:40 AM:

I just looked back at your first post, and I don't know where my mind was at when I made my post to you.
It sounds like the SDDS processor had a problem, and may have locked up into mute internally. I have not had this problem before, but I could see it happening. Sounds like you were listening to the Dolby's output on the booth monitor, but the SDDS was not passing it through to the amplifiers. If you don't want to play the film in SDDS in the future because of dropout problems, turn off the SDDS processor, and it won't matter if someone threads the reader or not. Then set the sound format switch on the automation to stereo. Unless the movie is mono, but that does not happen to often these days. If the film is SR, which is most common, set the sound select switch to the SR setting.

As far as the automation not starting the show, one of the failsafe arms may have been down.

------------------

quote:
"More human than human" is our motto.

Scott

Posted by Brad Miller (Member # 2) on 01-16-2000, 01:19 AM:

Sounds to me like the optical preamp went out and their SDDS unit is wired through the external digital input as opposed to being wired post-Dolby as is the norm.

Posted by Michael Cunningham (Member # 210) on 01-16-2000, 04:23 AM:

Did you get an alarm from the automation when you tried to start the show? This would indicate that the failsafe was preventing the start for some reason (i.e. arm down, film not in line with infrared sensors, etc.). If not, you may have had a fuse go on your automation. Sometimes, even if a fuse isn't blown, it will somehow break contact. This may be remedied by removing the fuse and twisting or flipping it in its holder. Then reinsert and see if it helps.

-Mike

Posted by Scott Ribbens (Member # 180) on 01-16-2000, 05:56 PM:

If the optical preamp went out, then they should not have gotten any sound in the booth monitor at all, as the SDDS was bypassed on threadup, and after the restart going from digital to mono they had sound . Is it possible that the automation is wired through the SDDS automation in/out puts? As I have never used those connections on the thing anywhere, is it possible that since the automation did not start the show that the SDDS was hanging up the output of the Dolby processor to the amps internally, if it is indeed hooked up normally? I don't really have any info on how the automation in/out puts work as SDDS failed to put that, and other key info in the installation and user manuals.

------------------

quote:
"More human than human" is our motto.

Scott

Posted by Joe Redifer (Member # 3) on 01-16-2000, 08:46 PM:

The Maxi12XPC automation is VERY sensitive to failsafes (unlike my CA21's). Were the failsafes up? Did you have the timer engaged or was it counting down from something else? The Maxi12XPC is rather odd. But it sounds to me as if you had your failsafes down.

The Mann Colony Square 12 uses Dolby CP65 processors in the bigger auditoriums and Ultra Stereo units in the smaller houses. THX in every auditorium. It sounds like you were using a Dolby CP65.

Posted by Erick Ojeda (Member # 216) on 01-17-2000, 06:57 PM:

Hi everyone,

Sorry it has taken me a while to respond. I spent the entire day working yesterday, and didn't get home until late last night. I checked the automation and I talked to one of the projectionists about the situations we have had the past few days. We found out that the show not starting on Friday was because the failsafe got stuck, and when that happens, we have to set it in the right position. I didn't know our failsafes were like that until yesterday. As far as the sound goes, we do have Dolby CP65 sound processors. I checked the model number last night. If I bypass the SDDS reader, would I have to turn off the processor controling the SDDS unit and run the show in Dolby Stereo SR? And if I did thread the reader, could I just hit the Dolby Stereo SR to get an alternative sound format instead of SDDS? I'm just a little confused on this area. I don't want to run Any Given Sunday in SDDS anymore because of the sound dropouts. After this week, I will see what happens with a different print, but for not I have to run Any Given Sunday for a few mroe days in the same house, and I want to get the best possible sound.

Erick

Posted by Aaron Sisemore (Member # 145) on 01-18-2000, 12:47 AM:

If your system has the SDDS wired in the 'recommended' way, between the analog processor and the amplifiers, you can do three things to make the system ignore SDDS:

1. Turn the SDDS processor off. This will bypass everything thru it.

2. Simply don;t thread the reader, leaving the SDDS processor on. Once again it will bypass everything if not reading valid SDDS data

3. If the reader is threaded and there is a horrible dropout problem, use the BYPASS button on the SDDS processor to engage the analog track.

In all these situations you may have to select the proper DOlby format if the automation sets the analog processor to 'digital' or 'aux' at the start of the show or via a cue.

Aaron