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Author Topic: dealing with soundtrack damage Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 02-13-2013 09:12 AM                        I received a print yesterday with good picture, but with platter/roller scratches in the soundtrack. It is not quite unlistenable, but the soft crackling sound is annoying. Is there anything that can be done on the exhibition side of things to minimize the impact of the scratches? Specifically, is there any benefit to slightly de-focusing the optics or is there anything else that can be done? This is a mono B&W print with a silver track. The theatre is using BACP LED readers. I have the equipment and loops to re-do the A-chain properly after this screening if necessary.  |  IP: Logged Mitchell Dvoskin Phenomenal Film Handler Posts: 1869 From: West Milford, NJ, USA Registered: Jan 2001 posted 02-13-2013 09:20 AM                     Base side, FilmGuard, emulsion side, not much you can do.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 02-13-2013 09:29 AM                        Try: using noise reduction even on mono. shorting ONE channel input, then the other. (Older processors, remove one NR card, then the other.) Best news of all, instantly back to normal. Louis  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 02-13-2013 10:43 AM                     Sounds like bacon frying? Not a whole lot you can do. Try FilmGuard. Even if the emulsion side is damaged, it will help a little. (Depends on how bad the scratches are.) Try different modes: Stereo, mono, noise reduction in our out. Past that, I can't recommend much else. If its a movie that will only have a short run, realigning sound heads and tinkering with processors might prove to be counterproductive. You'll spend all that time changing stuff, only to restore it a short time later. I would only consider making changes to the system if the movie is going to have a long run.  |  IP: Logged Sean Weitzel Jedi Master Film Handler Posts: 619 From: Vacaville, CA (1790 miles west of Rockwall) Registered: Dec 1999 posted 02-13-2013 11:15 AM                     I'm told LED readers exacerbate dirty or damaged tracks. One trick I've seen done is to put a piece of translucent adhesive (scotch) tape over the light source to diffuse the light somewhat.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 02-13-2013 11:24 AM                     Is it an archival print? You may not be permitted to apply a liquid cleaner, even if it will help. I'd ask first. I suspect Scott knows this, but I'm adding this note in case some future person finds this thread. It's likely that more and more prints will be sourced via archives as time passes. This sounds like a situation where an additional layer of outboard EQ's (normally in bypass) might help. Engage them when you get into a "situation" like this, dial-in a setting that works, and then bypass them to return to normal.  |  IP: Logged Jack Theakston Master Film Handler Posts: 411 From: New York, USA Registered: Sep 2007 posted 02-13-2013 12:07 PM                     Is it a density or area track? If it's an area track, what kind?  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 02-13-2013 01:45 PM                     quote: Sean Weitzel One trick I've seen done is to put a piece of translucent adhesive (scotch) tape over the light source to diffuse the light somewhat. This works surprisingly well (I think I was the one who showed you) and is something I always do for film collectors or sub run houses that are working with used prints. Do note you will have to slightly increase your current to the LED and run tone again to calibrate, but the benefits of the Scotch tape far outweigh not having it. Keep in mind it must be Scotch tape (the kind that you can write on that looks frosted). Sean, remember that old reel of film you brought over last year how clean it sounded? Scotch tape.  |  IP: Logged Manny Knowles "What are these things and WHY are they BLUE???" Posts: 4247 From: Bloomington, IN, USA Registered: Feb 2002 posted 02-13-2013 01:59 PM                     I just gotta try this!  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 02-13-2013 02:13 PM                        I have not made a direct comparison, but I do feel that the LED readers are more sensitive to print damage than an exciter/slit-lens arrangement. Curiously, the same is true for cyan-track prints played with white-light readers. I know of a theatre that did this for a while before converting to LEDs. They actually sound OK (though noisy) if the print is new from the lab, but damaged cyan tracks sound terrible on a white-list reader system. I will try the Scotch-tape thing tonight. Will also try playing in Dolby A and turning off the power amps for the other channels, which for some reason did not occur to me last night when I was testing things. Presumably the matrix decoding will help somewhat. Unfortunately, there is no way to create a matrix format without NR on the CP650. The backup plan is to show a collector print, but it has a different set of issue. Thanks for the suggestions.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-13-2013 06:24 PM                     LED readers are indeed more sensitive to scratches. The magic-tape theory does indeed work...I've done a couple of layers to get a very diffuse light...you definitely need to increase gain though.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-14-2013 09:03 AM                     If it is a dolby dp50 100 or 200 it is possible to set the A type cards to act as a DNR noise filter Hopefully someone can remember how I cant find my book on that  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 02-14-2013 09:50 AM                        Gordon, you either set the level too low or too high. That is what you are thinking. The Scotch tape thing does help with noise since it rolls off the highs and miscalibrates the dolby tone. Remove when done or you might as well have a Smart. (Don't think so? Run an A chain with the tape in place.) Louis  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 02-14-2013 10:18 AM                       Louis, your and my memory are going fast. But I do remember more than you about this issue. You can engage the filter on the 50 and 200. On the 50 with the original pushbutton switches, one could engage or disengage the academy filter independently. The 100 is fading from my memory, but the 364 external NR for surrounds did have a half and full NR filter but only for the surrounds. The 200 can be programmed to set a two stage filters one stage at a time. You have to create a custom format to do it. As to the tape, it works but it lowers the Dolby reference. You need to re-do the level to get back up to Dolby level. It has nothing to do with cutting high or low end frequency response. The best way to lower the sensitivity to dirt is to make sure the LED is right up close to the film, just sort of touching it. This has the effect of diffusion. For various mechanical reasons it is sometimes difficult to get that close.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-14-2013 04:43 PM                     As I recall, Dolby used the CAT 22 and then the CAT 280 like Gord was mentioning but in their 43 and then 430 series of processors. The CAT 43/CAT 430 allowed one to have control over the expanders so one can get a DNR like noise reduction but with the flexibility of adding as much expansion as desired/needed.  |  IP: Logged

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