Sync Digital Sound to Your 16mm Film Projector

In this instructable I'll show you how to modify an Elmo 16-CL projector to output sync pulses. Those pulses are monitored by free software I made ("Film-O-Sync") which plays back a soundfile in sync with the projector.

Traditionally, 16mm filmmakers have to choose...
Finish on film and make $$$ prints with lo-fi sound...
or...
Finish on video and get lo-fi picture with great sound.
This technique provides the benefits of good sound and good picture and it can be done with generally cheap materials and very little reliance on expensive lab services.

Keep in mind that this technique requires a certain workflow before you get to the projection stage.
1.) Shoot on film.
2.) Edit on film and add an Academy Leader or other visual countdown.
3.)Transfer your film to video using a method that guarantees a constant speed of 24fps or 23.98fps.
(That means a "sync" projector, a professional telecine, or perhaps a video recording of a well-maintained Steenbeck editor.)
4.) Edit your sound on a computer, using your video copy as a reference.
5.) Add beeps to your audio track, synced with reference frames on your leader.
6.) Export your sound as a single AIFF or WAVE file, with the sync beep as the first sound in the file.

I came up with this for students at Cooper Union Art School, where I work, so it's not a refined solution but it gets the job done and costs basically nothing. Most projectors have a similar mechanism, and you can probably come up with a design for the pulse-generator that fits whatever machine you have.

I wrote the software in MAX/MSP and tested it as a self-contained Mac OS X application. Windows is a possibility too, but I haven't tried it. Complete software info can be found in the download link provided in the last step. (including the source "MAX patch" which you are free to mangle, improve, etc.)

Step 1 Get Prepared

This whole thing is an improvisation, but here are the basic things you will need...

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Materials:

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A projector (In my case an Elmo 16-CL)

A computer (in my case an iMac 400mHz. Anything slower will probably cause problems.)

My Film-O-Sync software (link coming soon!)

A plastic pen or small dowel (somewhere around 1cm diameter by 3cm long)

A scrap of sheet aluminum or plastic (about 10cm x 5cm)

Some "magnet wire" to make a coil ( I used the 30gauge from Radio shack part # 278-1345)

A panel-mount jack (I used RCA)

2 tiny neodymium magnets (I used 1 pack of Radio Shack part # 64-1895)

Some shielded unbalanced cable (like a standard RCA audio cable)

A cable to connect your projector to the audio input of your computer. (I made an RCA->3.5mm cable from my scrap bin.)

Nylon wire ties, Super glue, Epoxy, Electrical Tape

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Tools:

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Soldering Iron

Exact-o knife

Wire-cutters / Strippers

Tin-snips or some other way to cut sheet metal/plastic.

Power Drill

Screwdrivers - (A long-shaft phillips one makes the 16-CL much easier to work on.)

Comments

[SyncFinder]

In one word; Fantastic!
This is just the sort of thing I've been thinking could be possible for 8mm, particularly as single system Super 8 (S8) is long gone. Even the development of software has been done for us.
It makes possible digital Hi Fidelity and it provides an opportunity to preserve what I consider to be the real S8 cine experiance.
My collection of S8 sound home movies goes back to 1974. The only real archive option is to create a digital version (Telecine) as 'zip' describes above.
For me, making such a digital copy is part of the S8 story.
Film is different to video. It's not better, it's not worse, it's different. It's different when shooting home movies not just because it has the image characterists of film but also because the cost factor infulences the shoot, at least it does for me. Watching projected film is a different viewing experiance. It's that experiance this clever process can help to preserve.
It's reasonable to expect the sound track on my Super 8 home movies will not last as long as the images so my digital archive must be undertaken soon, but once that's done, I still want to continue to use my films for projection. Not only that, but I also want to shoot new S8 with sync sound.
The demise of the single system S8 sound cartridge in the late 1990's was not the end of filming sync sound. A S8 camera with crystal sync modification used with a digital audio recorder (eg iPhone) does the trick. The crystal sync ensures accurate frame rates in the camera and a digital copy of that image can have sound married to it in the computer. This system provides the opportunity to extend this process to projeced film.
Thanks for shareing this. I intend to make good use of it.

[uzziah0]

DO you have any instructions on converting 8mm and 16mm film to a camcorder or something that can be copied to a computer?

[zlp]

If you're looking for a DIY solution, you may be dissapointed. There are professionals who can do it for you (the process is called "telecine") and a few DIY methods. Typically you need to setup a "film chain" which is a projector, relay lens, and camcorder. For 16mm in the US, the projector needs a modified shutter (usually 5 blades instead of 3) so the flicker will be tolerable. In PAL countries you just increase the projector's speed to 25fps. For Super8 in the US you need to project at 15fps instead of 18fps to reduce the flicker. Here is a vendor that makes film-chains (and does telecine services too): http://www.moviestuff.tv/moviestuff_home.html

Try a google search for "DIY telecine" and you'll find lots of ideas. Good luck.

[evanwehrer]

COOOOL my parents probably wont let me get a projector to do this. Let alone a camera to film stuff.