Comments

johnmeyer wrote on 4/14/2008, 7:47 PM
The only one I know of is this one:

Filmshooting.com

Unfortunately, it appears that the forum is down for a few weeks. However, here's a trick: use Google to search that site and then in the Google results, click on the "cached" version of the page, which will come from Google instead of the site. Here's a sample Google search of the site:

Chinon site:filmshooting.com

and this returns:

Search of filmshooting.com for Chinon


Edit: Well, it looks like this trick doesn't work, because many of the pages are too out of date, and also the forum requires a user name and password, which I have, but you probably don't.
RalphM wrote on 4/15/2008, 3:59 AM
Thanks johnmeyer,

Yes, I had book marked that site a while back, but it is apparently under reconstruction.

In the mean time, I've sprung for a Canon sound projector off eBay to see if the same problem appears for the batch of films I'm transferring.

Thanks,
RalphM
farss wrote on 4/15/2008, 4:21 AM
Perhaps if we knew what the problem is John or one of us could tell you if we've seen it before.

Bob.
RalphM wrote on 4/15/2008, 5:09 AM
Good Morning Bob,

It was so OT that I didn't want to post it. However, with a little encouragement....

I use a modified Chinon 5100 for transferring sound Super8 film to video. I also have a Chinon 4100 which is essentially the same machine.

If you ever as a kid put your face in front of a box fan and sang into it, you'll remember the chopped sound that was reflected back to you.

In the middle of transferring a large order, I noticed that some background music recorded in the customer's films had a sound very much like the fan effect. It doesn't show up on conversational speech unless someone is drawing out their vowel sounds. (In the days of open reel audio tape machines this would have been an extreme case of "wow".)

I assumed this was related to the film travel in the machine, so I went over all the potential issues - free spinning of the flywheel, no grease on the capstan roller, etc. I also put the film in the 4100 model and got the same thing. So maybe it's that way on the original... except that I got a Super8 trailer from "Showboat" produced by MGM, and it shows the same problem.

Thinking it was probably a slight speed wobble produced by the extra effort to run the feed claw, I removed the claw mechanism from the 4100 so that the load is uniform throughout the film feed. Same problem on both the customer's films and the Showboat trailer.

I don't have much hair left...

Ralph
JJKizak wrote on 4/15/2008, 5:24 AM
Since you tried another machine and have the same problem that means the problem is after the machine---cables, amps, etc. Are these magnetic tracks I assume?
JJK
RalphM wrote on 4/15/2008, 5:37 AM
They are magnetic tracks. However, the sound problem is the same whether I'm capturing via A/D converter or just listening through the projector's internal speaker....

Ralph
farss wrote on 4/15/2008, 5:43 AM
Does the same piece of film always play the same way?
A magnetic field could have affected a bunch of film, be careful where you store and place the reels. That'd cause partial erasure but no frequency shift so that's a long shot.

Or your mains frequency isn't stable. I can't imagine anything apart from either what's on the film or how it's being played causing wow, it was only an artifact of the mechanics of playing tapes and records.

Bob.
RalphM wrote on 4/15/2008, 6:08 AM
Yes, it always plays the same way in the same places. However, the effect is not alway present in similar sound situations. Example: a sustained vowel may have the chopped effect in one place but not in another.

I'd be really surprised if the mains has a problem. I live in a suburban area with a well developed power grid.

If I were to guess, I'd say the chop is related to the shutter speed which is why I keep chasing a mechanical issue. However, since the unit's motors are also running at some multiple of shutter speed, it's possible they are the cause of the problem. It could be a design isssue.

While looking for a projector of different design, I noticed that this basic Chinon unit was sold under several names. Probably 9 out of the 12 units I found on eBay were the same mechanical unit with a little different outer shell. That's why I bought the Canon unit on eBay this morning.

Ralph
JJKizak wrote on 4/15/2008, 6:19 AM
Don't discount the "Voodoo" problems you can have with ham operators, weather radars, military radars, numerous wireless stuff, which can all affect magnetic pickups.
JJK
craftech wrote on 4/15/2008, 6:29 AM
Have you tried this one?

John
RalphM wrote on 4/15/2008, 6:38 AM
Had not see the Google Group - I'll give it a try,

Thanks John
farss wrote on 4/15/2008, 6:48 AM
I should probably mention that I didn't transfer much S8 with audio. The stuff that I did do was pretty woeful, the low ips obviously didn't help at all. If I'd decided to stay in the business I did consider looking at using a R2R deck to try and get better audio off the mag strip.

Bob.
RalphM wrote on 4/15/2008, 7:27 AM
I actually did try two R2R tape decks to recover this sound. The mag stripe on the film is on the edge so it does not line up with the playback heads. i did some shimming, etc to get it over the heads but could not get any signal at all. No clue as to why that would not work to some degree.

ralph
johnmeyer wrote on 4/15/2008, 9:56 AM
1. If you are getting a "chopped" effect like listening to your voice reflected in a rotating fan, then external magnetic field is out, because that would affect one side of the reel more than the other and you would get something that would fade in and out once per revolution of the supply reel, which would be quite slow.

2. I have heard various kinds of "motorboating" sounds on film sound tracks, but those were optical tracks and were caused (I think) by misalignment of the pickup, and it started picking up the actual picture image, and the gap between each frame causes a 24 Hz. buzz, the higher order harmonics being particularly nasty.

3. If this was happening on just the one projector, then I'd certainly suspect the pickup electronics. If you have it happen on more than one projector, then almost by definition must either be on the film, or in the environment. I would certainly try taking the projector and film to another house or office and briefly listen to it there. It is amazing, as others have already pointed out, how much junk is transmitted through the air and through the power lines. Some equipment does a beautiful job rejecting this, but other equipment -- especially things made years ago, and things using tubes -- have very little RFI rejection designed in.
RalphM wrote on 4/15/2008, 12:00 PM
Thanks for all the inputs above, I'll give some feedback when I think I understand the cause...

Ralph
RalphM wrote on 4/30/2008, 9:06 AM
Since I promised some feedback when I had "solved" the problem, I'll offer what I think is happening:

After tearing my machines apart and chasing all possible permutations of the problem with the chopped audio, I’m now believing it is a product of the audio AGC in the original cameras combined with the mic being close enough to the camera to pick up the sound of the shutter.

I noticed that when the mic was actually visible in the scenes, being hand held by the speaker, there is no chop detectable. However, when the sound source is obviously some distance from the mic, the chopped sound becomes apparent. In some cases where there is a quiet scene, I can hear the sound of the camera shutter increase in level as the AGC ramps up. I believe the mic was being held close to the camera at that time.

This effect is more noticable with one client's films than with the other's, and it is the same on three different projectors, so I'm believing it really is recorded on the original films.

Thanks for the help to all those who offered suggestions.

RalphM