shooting sound without crystal sync

[Actor]

I sense that there is a basic misunderstanding here about what Pilotone (or cable sync) is and how it works.

"The theory behind piletone[sic] (which is numerical coding on the tape)?"

Wrong! Pilotone is not numerical coding. What you are thinking of is time code, which is completely different.

"In order to coordinate the Nag and the camera the sync signal must be related to the camera speed?"

Actually the sync signal is related to the difference between the camera speed and the Nagra speed. This is an important distinction.

"So a 60hz frequency (from the power-line)recorded on the sync track will be at exactly the same frequency as that driving the camera, any variation in camera speed caused by fluctuation in power-line frequency will be reflected to the sync trac."

This implies that the camera is driven by power from the 60 Hz mains. Not true.


"So piletone would also be an option for you, if this super 8 hookup that actor suggests is available"

It's available from The Film Group at http://members.aol.com/fmgp/index.htm

"I would almost guarantee it to cost a lot, which might not be too practical for a super 8 short."

The price is $300. Compare this to $500 to add crystal sync to what is already a pricey camera. The digital to pilotone converter will work with any camera that has a PC.


Hollywood's original solution to the sync sound problem was to combine the camera and sound recorder into one unit with the camera's film sprocket and the recorder's mag track sprocket on the same shaft with the same number of teeth. This resulted in a rather large ungainly instrument and other solutions were sought.

What they came up with was to drive both the camera and the recorder with synchronous motors (similar to those used in analog electric clocks) powered from the mains. This worked fine in the studios but not so well on location. The obvious solution of synching to portable generators was abandoned for reasons I do not know. I suspect that the frequency of early portable generators was not that stable.

The next step in the evolution of sync sound was to modify the synchronous motor of the camera so that it could be battery powered and at the same time generate an A/C tone whose frequency would be 60 Hz at 24 frames/second. This tone would be fed to the sound panel via a cable, amplified and used to drive the mag recorder. It worked but was still bulky.

Enter the Nagra! The German company's system was to use battery power to power a simple ? inch tape recorder and record not only the sound but the 60 Hz tone from the camera. Both the camera and the Nagra's speed could vary. The frequency of the sync signal would be proportional to the difference. 2? cycles of sync signal on the Nagra would correspond to 1 frame in the camera. (When filming at 25 fps the tone is nominally 50 Hz and 2 cycles of sync corresponds to 1 frame.)

With crystal sync the sync motor guarantees that the camera will be framing at exactly 25 fps +/- one part per million or some such. A common misconception is that the Nagra's motor is also crystal synched, but it is not. Since the Nagra uses unperforated tape slippage at the capstan could cause the system to lose sync. Therefore a crystal oscillator in the Nagra generates the same sync tone that would otherwise be provided by the cable.

"My gripe against pilotone is the fact that you are connected to the recorder. The whole reason crystal sync was invented was to get rid of this pain."

Right! But the question being addressed here is sync sound without crystal. And you don't need an expensive Nagra. Any stereo recorder will do if you're will to settle for mono. My camera cost less than $50. A reel to reel stereo recorder off eBay was less than $100. $300 for the digital to Pilotone converter and I'm set for less than the cost of a sync motor alone.

Actually I think I could gen up the convertor with a few parts from Radio Shack for a lot less than $300. I'm still working on the design. We'll see.

[Nigel]

Actor--thanks for your views and opinions. I like to see other people out there that love film too. Nagra is a Swiss company, founded by a Polish man named Kudelski. I love my Nagra I wouldn't sell it for the world. I am glad that you cleared the air on some issues.

[JoeAverage]

OK, so you have your nagra or your little cable or some cristal dealies and its all fifty hertz like anything and plugged into a line voltage with batteries made in switzerland and/or germany... So how do you show a sound movie?

[Nigel]

You don't these days on Super8. You either transfer to video and sync it up at the lab or on an AVID. Or you do it by blowing your Super8 to 16mm or 35mm and sync it the old fashioned way--then get an answer print and release prints made. It is to hard to explain here.

[mattias]

nigel is right, but in theory there's another way. if you don't want to edit the film, you can just connect your nagra to you pilotone controlled projector and go. you have to stop and resync for every scene of course, unless you had the nagra set up to start and stop in sync with the camera. if you have to edit, you must resolve the audio to super-8 mag. easy to do, if you can find a mag recorder. there are probably places where they can still do it for you. then you just cut and splice the usual way and use a double system sound projector to screen it, or transfer back to tape with pilotone to control the projector.

[Actor]

http://freespace.virgin.net/k.mayes/...m/KJMfilm4.htm

[ekoe]

i've contacted kevin at the url address referr'd to in the previous message. he's the inventor of the klm projector synch system. although it looks hopeful, his synch system is still in the works. he needs feedback from super8 filmmakers. provided some projectors (such as the elmo gs/st 1200's and the braun visacustic's) have pc contacts, there must be a way to obtain synch. perhaps by amplifying the pilot-tone and using that 60/50hz signal to power the playback mechanism? i'm not so technically inclined as some, but i'm determined to make it work somehow. just don't like the idea of projecting video. that's an itchy compromise with me.
another option is to petition the filmgroup to develop a crystal synch unit for projectors. i think they'd do it if we'd prove there's a market.


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