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Author Topic: Cyan Dye Track Experiences with "Anything Else" Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 09-30-2003 09:16 PM                    Getting back to analog... Somewhere there exists cyan tone and cyan noise as they would have no comparative data without them. The question is how can I get some?  |  IP: Logged Aaron Sisemore Flaming Ribs beat Reeses Peanut Butter Cups any day! Posts: 3061 From: Rockwall TX USA Registered: Sep 1999 posted 10-01-2003 12:55 AM                     I have a roll of cyan tone film that I got from USL. Haven't seen cyan pink noise film yet. -Aaron  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 10-01-2003 01:03 AM                     Maybe he means Dolby Noise --jhawk  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 10-02-2003 10:10 AM                     "Dolby Noise" actually exists It is a warbling noise recorded on SR mag to identify that it is SR encoded at ref level compared to the Warble tone of true dolby tone recorded to id dolby A material mag elements  |  IP: Logged Kirk Mitchell Film Handler Posts: 2 From: Blacksburg VA Registered: Oct 1999 posted 10-03-2003 03:36 PM                     Well I got to screen this movie in a DTS house. This particular house has a problem with the analog reader that creates a slight buzz in the auditorium. My tech thinks I'm a nut because "he can't hear it", or maybe more likely he doesn't want to hear it. So on to the screening. Started this up waited for the movie then I hear that noise that said it was reading off the sound track . I realized I forgot to put the DTS disc in so I ran upstairs and put in the disc made sure it switched over to DTS. Ran back down to the theater. It all sounded a lot better. So throughout the film I heard the buzz coming in and out. I can say the levels were not a problem but It seems the DTS reader could not get a consistent time code. I haven't had this problem in this house with any other print. So naturally I wonder if this has something to do with the cyan dye track. So I guess I would like to know if anyone else had this problem. Or was this just some fluke that happened to coincide with this print.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 10-03-2003 09:16 PM                     nope since dts has always used a red led that isn't your problem  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 10-03-2003 09:21 PM                        Since you have had the buzz in analog for quite some time without repairing it, it's highly unlikely the cyan track was at fault. And as Gordon notes, the red LED in the DTS reader is fine with cyan time code.  |  IP: Logged Ray Derrick Master Film Handler Posts: 310 From: Sydney, Australia Registered: Sep 2001 posted 10-04-2003 09:06 AM                     The consequences of playing a cyan soundtrack on an exciter lamp system or infrared reader go far beyond a mere loss of level and increase in noise. What John Pytlak (and for that matter, Paul Goldberg) fail to mention is the effect that the Dolby noise reduction circuits in the cinema processor have on the soundtrack when the level of the incoming playback signal is well below the normal calibrated reference level. An essential requirement of all Dolby noise reduction systems is that the level of the playback signal must precisely match that of the record signal, otherwise serious dynamic and spectral mis-tracking will occur. Hence the primary reason for the existence of Dolby Tone, to allow this precise matching to be achieved. Because the noise reduction circuits are "programmed" to dynamically reduce the level of lower level signals, a signal that is already 12dB too low will be confused with normal low level signals and be further reduced by the NR circuits. But much worse than that, because the NR circuits have various built-in thresholds, things like dialog (which by it's very nature varies over a considerable range of levels) will "pump" badly because it no longer matches the threshold levels used during recording. Furthermore, because the NR circuits are now behaving in a totally unpredictable fashion, the matrix decoder circuits (which follow the NR circuits) will also seriously mis-track, resulting in increased surround crosstalk and instability of the centre channel sound image. As Michael has already discovered, no amount of winding up of the fader can fix all of this, the only option is to play the soundtrack in mono which disables the NR circuits and provides some brute force filtering of the additional noise. Even then the results will be very poor because the soundtrack is compressed and spectrally modified by the NR system during recording, so without a complementary system during playback, background sounds will be far too loud compared with things like dialog and the spectral balance will drift all over the shop. The ONLY way to play a cyan soundtrack is with a red light source. Nothing else will provide even partially satifactory results. [ 10-04-2003, 10:17 AM: Message edited by: Ray Derrick ]  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 10-04-2003 09:20 AM                     Why is jacking up the preamp gain 12dB (ideally with cyan Dolby Tone) insufficient to address SR (or A) mistracking? --jhawk p.s.: Yes, I know what Dolby Noise is, Gordon. Otherwise it wouldn't have been funny!  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 10-04-2003 09:24 AM                     Increasing the preamp gain will also put the noise floor so much higher that it will still predominate as the NR circuits will not be able to deal with it  |  IP: Logged Ray Derrick Master Film Handler Posts: 310 From: Sydney, Australia Registered: Sep 2001 posted 10-04-2003 09:33 AM                     Of course increasing the preamp gain using cyan Dolby tone (which currenty doesn't seem to exist) will overcome most of the mis-tracking problems except, as Gordon points out, the NR will probably have trouble dealing with the relative increase in the noise level. That's another 12dB of noise don't forget. But if you "jack up" the preamp gain and along comes one of those sneaky little silvered soundtracks, you will most likely overload the front end of the preamp, not to mention destroy the audience's hearing and also the noise reduction will no longer track the silvered stuff because the playback level is now way too high. This will result in the silvered soundtracks sounding noiser that before because the NR ciruits will confuse the noise with higher level signals and will not reduce it as much as it should.  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 10-04-2003 09:41 AM                     I don't think anyone is seriously proposing this as the Right thing to do, we're taking about what to do as a temporary measure if you find yourself in an ugly stew like this. Sure, it'll be noiser. But it'll be noisier if you increase the fader (i.e. post-NR gain stage) by 12dB, too. I wonder how much of Gordon's comments are speculation. I suppose the question is whether the gain you get by jacking up the preamp hurts your NR such than increasing the fader would have been better. I guess I don't understand enough about SR or A (and the answer might be different; perhaps it might make sense to play cyan SR prints with A-type noise reduction if you're going to play them with white light) to know. And I supppose there might be some strange effect such that it was best to raise the preamp by 6dB and the post-NR gain by 6dB, or 3+9dB, or 9+3dB, as opposed to the hypothetical 0+12dB or 12+0dB. I suppose we're unlikely to know what is best. --jhawk  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 10-04-2003 09:53 AM                    I have red LED basement readers at the screening room so this is purely an academic exercise but with cyan tone I would like to see, using other conventionally equipped machines, just what could be accomplished by cranking the hell out of the exciter bulbs and topping it off with pre-amp adjustments. It's just out of curiousity.  |  IP: Logged Ray Derrick Master Film Handler Posts: 310 From: Sydney, Australia Registered: Sep 2001 posted 10-04-2003 09:56 AM                     John, Gordon's comment is fact, not speculation. Say hypothetically you are stuck with an exciter lamp, there is no way to convert the soundhead AND you will never play another silvered soundtrack. Then the best option is to recalibrate the preamp gain using a cyan version of Dolby Tone. But we all know silvered tracks will hang around long after cyan becomes commonplace. So the only option is not to get caught out in the first place by converting all your remaining soundheads to a red light source as soon as possible. Using Dolby A on an SR track will not help, it will still badly mis-track. If you get caught then go to Academy Mono as Michael did. Steve, if you could increase the light output from the exciter by four times (which seems rather unlikely) you would solve the problem for cyan tracks but you are still left with way too much gain for silvered tracks. Red light is the only light source that results in about the same output level for both cyan and silver redeveloped tracks.  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 10-04-2003 05:51 PM                        John Italian's print of the movie does not have the Cyan Dye analog soundtrack but a standard soundtrack... Bye A  |  IP: Logged

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