Film-Tech Forum ARCHIVE: Recording pix and sound separately

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Posted by John Walsh (Member # 168) on 05-04-2003, 03:23 PM:

First, some background.... We recently bought two large format Kinoton MK75's: projectors allowing us to run 4/35, 5/70 and 8/70 prints. Apparently, we have the only two in the US. These auditoriums have 70mm DTS readers, biphase generators and (for audio) DAT tape (and hard drive) recorders. We were glad to get them, because now we can run the standard large format educational stuff during the day (if I had to sit through 'Mysteries of Egypt' one more time, I'd barf) but then run regular product at night. Simply put, this allows us to make more money in those auditoriums. We'd like to book regular 70mm prints there for, say, a 70mm festival to get even more use.

The problem is, we do not have a 70mm mag head for these projectors. We could probably get them, but I know it would take a long time. I don't think one was actually designed for it yet, and they would be very expensive. There just aren't very many of them around. Even so, I probably couldn't justify the cost for the few times we'd use it.

So, I'm wondering if we could bring a 70mm mag print to one of our 'regular' 70mm auditoriums. Put the print together, put a biphase generator on the projector, run it and 'record' the mag tracks onto the DAT recorder (a DA98.) Then, bring the print to our LF auditorium and run the same print with the sound comming from the DAT. It would take some work, but still much cheaper than the cost of the two mag readers.

Could it work... even so, would it be bogus?

Posted by Scott Norwood (Member # 30) on 05-04-2003, 03:40 PM:

It's definitely possible, but you'd need a tape format that carries more than two tracks if you want to reproduce 70mm soundtracks properly, along with some outboard processing to decode any NR that might exist on the 70mm tracks.

You probably could do it with a DA-88 machine or 8-track reel-to-reel, although they aren't especially cheap, either. There would also be some running-time limitations. At 15ips, a 10.5" reel (2500') would run for only about half an hour. DA-88 tape runs for longer, although I don't remember the exact length.

Hopefully someone else can comment on the technicalities of synching the projectors to the tape recorder (probably using timecode generators on each).

Posted by Bruce Hansen (Member # 281) on 05-04-2003, 04:08 PM:

If I remember correctly a DA-88 will do 113 min. max. The problem would be getting the two units to sync up to the same place every time. Do you happen to have a mag film reader, that will sync to by-phase from an encoder on the projector? Does your projector have the mag "penthouse", but not the mag head? If so, mabe you could find a used one somewhere. Just make sure it is not worn too badly (you lose high freq. resp.).

Posted by Steve Kraus (Member # 476) on 05-04-2003, 04:25 PM:

What are your "regular" 70mm machines? If it was an undriven penthouse like an X-L could it not be applied somehow to your new machine?

Posted by Matt Hale (Member # 1518) on 05-04-2003, 05:02 PM:

DA-98s do not have a biphase input. You are going to need at the very least a biphase to word clock converter to make sure everything runs at the same speed, and optionally a biphase to timecode converter to make sure everything is running in the right place at the right speed.

But it can be done. I used to sync all manner of multi-track devices to our Simplexes, starting with biphase and converting it to whatever the particular machine accepted for sync.

Posted by Phil Hill (Member # 371) on 05-04-2003, 05:12 PM:

Your DA-98 could be used with a DTS E-175 to convert the bi-phase tach signal to SMPTE TC for the 98.

>>> Phil

Posted by Steve Guttag (Member # 268) on 05-04-2003, 05:56 PM:

I just gave the MP-75 manual a peek...it does list a threading with Magnetic sound. Therefore, I suppose that a mag sound head (Com70) would have been an option when you ordered your projector(s).

The 70mm mag system seems to be the DP-75's maghead (complete with sprocket and goofy film pad). So, in order to upgrade your machines to magnetic capability, you may find it cheaper to find some good/used DP-75s and take the mag stuff out.

My guess is that you will need a new top-most panel with the cutouts for the magnetic stuff and that the torque motor reel drive will need to live in a penthouse...neither of which should be too expensive and definately less hassle than duping films on a case by case basis. Give Kinoton America a call...they will probably roll their eyes at first but it is probably doable with just some effort and reasonable cost, once the DP-75 head(s) can be located.

As to duping the films...what a pain. Once you have a suitable medium (regardless of type) then each film will need to be duped on a print by print basis and in the event a film breaks or gets mangled, you will need to slug the picture to keep it matched to the sound. I don't deny that it is certainly doable just more effort on an ongoing basis. Factor in the revenue on one good 70mm playdate and you would have bought your 70mm mag equipment.

There are a couple titles now available in 70mm DTS...like Lawrence of Arabia and it is likely that future reissues will have the DTS offering.

Steve

Posted by Larry Shaw (Member # 388) on 05-06-2003, 06:29 PM:

John,

So far there are 3 MP-75E's in the US, and there is a mag upgrade kit that was installed at the Cinerama Dome. Delivery time isn't crazy, but obviously it's not "off the shelf".

Posted by John Walsh (Member # 168) on 05-06-2003, 08:38 PM:

Hi there, Larry!

Yes, as you might have already guessed, I'm trying to do this on the cheap! But, what at first glance seemed like something that might work, as too many problems...

I could record it from the CP200 output to have a nr decoded, but it might be to noisy... the tape won't run long enough, although we do have a biphase on the projector and a Ketchum box to drive the DA98's.

Steve (and Steve's!) idea about adapting the mag from a DP75 is interesting, since we have four of them that I know will never run 70mm again.... Thanks to everyone!

Off topic, but..

I'd like to mention that BL&S / Kinoton America hosted an excellent seminar on Kinoton projectors, (with emphasis on the PK60) a while ago. I braved those crazy Boston roads and it was well worth it. It was very through and we actually took projectors apart, made adjustments, etc. Factory reps from Germany were there for questions and told things you needed to know, even if it was something like a design flaw or other factory error .... everyone had a great time. The reps kept apologizing for their bad english, but frankly they spoke better than some of the native Americans working at some of our theaters... [Smile]