Recording sound with a CD turntable.

[Vespasian]

This is something we should all think about.......hmmmmmmmm..........okay I'm done it's genious. I mean think about the cue button can exact a point in a CD and I mean exact it to the millasecond, and hold it there. A CD TURNTABLE of course has a PITCH BEND which can be used if the sync is thrown off a bit. Even the cheap ones have like three different time patterns you can use. A good cheap choice would be the Gemini CDJ-10 about $160 new, but you can probably win one on ebay for about $80. I mean this would be an awsome tool, just hook it right up to the projector. Of course you would need a cd burner. Anyway tell me what you think. If you need to know more let me know.

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[#Pedro]

Hi Vespasian,

not a new idea you aready can BUY such kind of equipment ready.

The great problem concerning simple, home-made solutions is that "only hook it up to the projector". And what?s about soundtrack editing?

Well, the existing solution (system Gebuhr Multisyn) works like that:

The ready edited soundtrack CD has two tracks. The first track is a so called "init" track containing tone signals to set the sync electronic to the desired framerate and the CD-player to the slave mode. The CD-player is "hooked up" to the projector, connected to it?s reed contact.
Then you start your film, that has already been loaded and adjusted to it?s sound start mark. The CD-player now is receiving pulses from the projector (1 per frame) and starts automatically the soundtrack (track 2). THe in-built sync electronics always compare the projector?s framerate with the speed of the CD and makes the neccessary adjustments by itself. I?ve seen it working, it?s perfect.

The problem is the creation of the soundtrack CD. You must produce a master sound source, that is in sync with the footage. The usual way to produce that master tape with the Gebuhr Multisyn system goes like that:
You load your film into the Gebuhr editor and a perfo tape to a Gebuhr-modified standard tape recorder (reel-to-reel). An optical scanner (optocoupler) senses each hole of the perfo tape and the counter shows the actual number. When moving the perfo tape foreward or backward, the film is moved automatically in the motor viewer forward and backward, exactly the same number of frames as the number of perfo-holes.
This way you can record whatever you want to the perfotape is excellent master quality, always watching the film in sync.
For longer films you should make a sound story board with frame numbers.

After finishing that master tape, you need the Gebuhr Multisyn CD-burner. This burner outputs a framerate reference during burning. That signal controls the speed of the master tape player during playback and recording to CD. Only this way, you can produce a soundtrack CD, that is really in sync with the film (frame-accurate).

The complete system is working perfectly, is used for commercial and semi-commercial productions with 16 mm and S8 films and very easy to handle. But as you can imagine, it?s as expensive as the rest of the equipment!


Simple, wild-synced solutions don?t really work, I?ve just tested it. It?s simply not possible to pitch control a complete film manually during screening.

As the Gebuhr system is too expensive for me, I?ve built my own one, that?s working frame-accurate, too, but without CD-option.

Well, when using the syncable ELMO GS1200MO, I can go over CD. During burning, the playback mastertape must be hooked up to a crystal with 24 Hz, and during playback, the ELMO must be hooked up to that crystal, then it works. The same possibility I have with a Bauer projector, that I have modified.
But many other projectors with AC motor can?t be synced so easy. Then you only can sync the sound source and to do that, you need a sync track on the sound source or a perforation, that gives you a speed reference for regulation. And CD has only two tracks, for stereo, no 3rd track for syncing.

Pedro


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[Vespasian]

Yeah but you don't have to go through the whole film, and if need be you can record over a part where you messed up, wild sync systems do work. It is called practice before you press the record button. You just practice when to press the button, you can practice on every scene if you need to. For a 30 to 45min. feature wild sync works very well especially with pitch bend. GOD I NEED A FRAME COUNTER!!!! Hey Pedro any ideas on how to hook up a frame counter to a projector without one?

ALERT: If you want to sync sound well with a wild sync method buy a sound projector that has a FRAME COUNTER I didn't, and it still hurts.

Hey thanks for the input Pedro I apreciate it. Any new sources for striping machines?

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[#Pedro]

Hi Vespasian,
for sound transfer to strip it works more or less, I practiced it over years. But a whole film during screening - no thanks, too much stress! I tryed it, too, but abandoned it.

For accurate recording, you really need a frame counter.
This will require several steps:
1. attach a reed contact to the projector, that gives you a 1 per frame reference.
2. look in electronic shops for ready UP-DOWN counter panels (cheap). Important, that the counter can easyly toggle from up to down, without dealing with complicated menue inputs. Most counter panels have 4 digits, what may be sufficient for finding the recording point.
3. Connect the reed contact to the countin input of the counter and to the power supply.
4. Apply a momentary switch or another reed contact to the projector, that becomes activated, when the projector is switched in reverse mode and connect this switch to the reverse input of the counter.
5. apply a relay to the zero detect output of the counter. The relay will be activated, when the counter goes to zero and start your sound source to record when passing from 9999 to 0000.

If you don?t find a matching counter module, you can built one by yourself, using the Intersil circuit ICL7217A and 4 LED-digits with common cathode. It?s easy and secure to built. I am using this kind of counter for perfo soundtracking.

For stripers, I only can recommend regualary search ebay...

Good luck,
Pedro

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[Vespasian]

Hey, Pedro thanks again for the input. I have a Sankyo sound 600. So it is possible to connect a frame counter to a projector that dosen't have one? I had kind of a hard time understanding the procedure in adding a frame counter, they sound really complicated. Could you maybe simplify them a little?, if not thats okay I'll try my hardest to figure them out.

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[Vespasian]

Pedro! I found a Digital LED counter/totalizer, it has 6 digits, a reset button, and 2 wires coming out of it. The person who is selling it says that when the 2 wires touch the counter goes up 1 2 3 and so on I guess it dosen't stop until the wires are untouched. Will this work? Hey Pedro do you think I could get your email address, I really apreciate you helping me through this.

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[#Pedro]

Hey Vespasian!
There are several steps required to add a coutner to a projector (I don?t know your particular model, but it doesn?t matter).

Concerning your counter, there is nothing said about how the reverse mode is set, if it is a single event counter or a frequency counter. THerefore it is difficult to give an answer.


1. first you must CREATE an electrical signal which tells the counter when it should increase or decrease it?s value. This is easyly made using a reed contact. A reed contact is a cheap device whith a switch inside, that can be closed from extern using a solenoid. Bringing a solenoid close to the reed, the contact will close as long as the solenoid is there. This way, you can glue a small solenoid onto a component of the projector, that is moving or rotating once a frame. Maybe a drive reel or the shutter blade. Simply try it, open the projector and turn the drive reel by hand. Find any component suitable for glueing the solenoid, that turns once a frame. Then glue the solenoid with 2-component epoxid glue and mount the reed close to it. With an ohmmeter of beeper you can check, if the reed is closing every time when the solenoid is passing by. The two wires of the reed you connect to a 6pin DIN connector. On wire to pin6 (in the middle), the other wire to pin 3 (top position). Drill a hole of 15 mm into the projector?s cover and mount the connector

2. Now you must create an electrical status signal that tells the counter, that the projector is running backwards. Again you best use a reed and a solenoid. Fix the solenoid to the mode knob of the projector and the reed in a way, that is is activated in backward projection mode. Connect the two wires to pin 3 and pin 1 of the connector. Now you have a connector with "common ground" at pin 3, "frame pulse" at pin 6 and "backward" at pin 1.

3. If you are lucky to find any terminal inside the projector that has a DC voltage of about 7....25 V, you can connect it to pin 2 and the ground of that voltage to pin 3. This could be used as a power supply for the counter.

4. Get a panel counter with meets your application, that is single event counting, increasing or decreasing mode, resetable and zero detection output.
Mount the counter into a plastic box and connect a 4 pin wire to it, with a plug according to the projector?s connector. According to the required supply voltage of the counter, connect it direcly to the projectors voltage (pin 2) or with a voltage regulator according to the required supply voltage. (f.e. a regulator 7805 for 5 V supply). Connect ground to pin 3, count input to pin 6 and reverse mode input to pin 1. Now the counter should work according to the projector.

5. If desired, connect the zero det. output to a small relay and the relay contact to another connector, mounted to the plasic box. This is for remote start of external sound sources when the counter goes to 0000.

6. If you cannot find a panel counter according to your application, I can provide you diagrams to built one. Not expensive, some hours of work, standard components, not dangerous.... and fun.

Any questions, please feel free to contact me.

Pedro

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[This message has been edited by #Pedro (edited November 08, 2001).]