This is topic Edge sensing foil cue going through CAT 702 causes pitch shifting in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=006876

---

Posted by Mark J. Marshall (Member # 1409) on 01-16-2005, 02:27 PM:
 
Subject says it all. Our automations use outboard edge foil cues, and at the end of the film, when the credits are about to start there is usually bit of dramatic music, and it never fails... a long dramatic note has a bad case of pitch bouncing higher and lower and higher and lower as the cue goes through the CAT 702 reader. Any way to combat this? The processor is a CP 650.

Thanks,
Mark
 

---

Posted by Steve Guttag (Member # 268) on 01-16-2005, 08:56 PM:
 
You say your automations used edge sending cue detectors...what kind are they?

I presume you are folding the cue tape over the edge of the film...is there any reason you need to do this? Can you apply it to the contact side (if electric) or the sense side (if prox) and merely trim the tape and/or perforate it so that it does not cause the instability going through the reader?

Steve
 

---

Posted by Mark J. Marshall (Member # 1409) on 01-16-2005, 11:42 PM:
 
Thanks, Steve. I'll check on the cue sensor model and get back to you. Yes, we fold the cue tape over the film and it stretches from the outer edge of the sprocket holes on the base side to the same edge on the emulsion side. Are you suggesting that we cut the cue tape in half down the middle (boy, that will be fun trying to teach that! )? And then the second suggestion is to put the cue tape all on one side of the film and puch holes with a splicer? That would cover the SRD entirely and make it drop out completely, wouldn't it? That would rule that out.

Does anyone make cue tape narrow enough to only cover the film from the edge of the sprockets to the edge of the film without folding it over? Basically only covering the SDDS-S track?

Thanks again,
Mark
 

---

Posted by Brad Miller (Member # 2) on 01-17-2005, 04:17 AM:
 
No, just lay the film down flat on a table. Then lay your stretch of cue tape across the edge, butted up against the edge of the sprockets (covering the SDDS area) and the rest of it hanging off of the edge of the film. Then trim it clean with the edge of the print carefully using scissors.
 

---

Posted by Monte L Fullmer (Member # 2797) on 01-17-2005, 04:41 AM:
 
...now, I'm gonna ask a dumb one here: Being a digital read from the film using the CAT-702 penthouse reader, would such a small case of film speed variance, like this topic of cue tape placement on the edge of the print (sounds like an old SPECO cue reader) causing such audio variances, cause such a deviance in analog playback even though from a digital source which is just data, not an analog waveform?

Also, since I'm not familiar with the CP-650, being that we don't have any of these newer processors, wouldn't the 650 have some sort of cache to store a small amount of digital data information(like DTS) in case of digital dropout from the reader if the cue tape placement is causing these dropouts by moving the film slightly from the LED/camera alignment to fail out, thus switching over to analog (05) when the fail comes, and hearing this variance in sound?

And it seems that the cue has to be at least 4 inches long for the roller to ground connection to be complete.

thx-Monte
 

---

Posted by Mark J. Marshall (Member # 1409) on 01-17-2005, 08:38 AM:
 
Thanks guys. I'll give that a try and see what happens. I'm curious...

Another theater where I work uses all the same equipment on the projector/automation/cue detector side, but uses a CP 65/DA20/Cat 699 set up, and they don't have this problem. What changed?
 

---

Posted by Monte L Fullmer (Member # 2797) on 01-17-2005, 02:02 PM:
 

quote: Mark J. Marshall

---

CP 65/DA20/Cat 699 set up, and they don't have this problem. What changed?

---

...makes one wonder if your CAT-702 needs a bit of a "A-chain" alignment then...

- could be more sensitive to this cue thing where CAT-699 uses that filament bulb, fibre optic device instead of the LED.

Plus, you have two readers that are almost a good 10 yrs apart in technology - like carburetion and fuel injection.

Plus, older CP-65 processor with that DA-20 attachment which could be not as sensitive as the CP-650 in certain issues.

Overall, comparing an old system to a new system, isn't really fair with all the advance changes that Dolby has done with their products.

- Monte
 

---

Posted by Mark J. Marshall (Member # 1409) on 01-17-2005, 03:44 PM:
 
It sounds like the older systems would cache the data and pull it out of cache at a constant rate that assumes 24 frames per second, while the newer system interprets an increase in the speed of data coming in as a sign that the sound needs to "speed up" exactly as it would if it were analog.

I have no idea if that is the case, I'm just strictly speaking from a programmer's perspective. If that is the case, I guess it's a cool feature, but you should be able to turn it off. If that's not the case, then obviously I don't know what I'm talking about!
 

---

Posted by Gordon McLeod (Member # 33) on 01-17-2005, 08:21 PM:
 
The wow is probably a set of very rapid reversions from digital to analogue and back
 

---

Posted by Bruce Hansen (Member # 281) on 01-18-2005, 12:32 PM:
 
Watch the film path of the reader as the cue goes through. Do you see anything changing, such as the film riding in a different place on a roller, or sprocket? This problem sounds like the system is being told that the film is changing speed. The film bowing out as it goes through the reader, because of the stiff cue, could cause this. Do you need a little more tension on the film as it goes into the reader?
 

---

Posted by Monte L Fullmer (Member # 2797) on 01-18-2005, 01:19 PM:
 

quote: Bruce Hansen

---

Do you need a little more tension on the film as it goes into the reader?

---