8mm Forum: Soundtrack mystery

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Posted by Phil Slater (Member # 2388) on July 11, 2016, 07:13 AM:

A few months ago I aquired one of the 200 foot super 8 sound Glenn Miller extracts. As you may know, the quality of the sound is not very good on these prints, so I re-recorded it on a Goko recording editor using a youtube video. I ended up with a good quality soundtrack on the film and was very happy with it. I have played it many times since on various projectors.
Now here comes the mystery, when I play the film now, I am noticing sound drop outs where the sound level reduces momentarily about 3 times in succession, and this seems to repeat every 5 or 6 seconds thoughout the film. At first I thought the soundheads needed cleaning but no, its the same on all the other projectors. How can it suddenly deteriorate like this?
There is nothing visibly wrong with the soundtrack and I haven't stored the film differently to the others. I have used this technique of re-recording soundtracks many times and not had this problem.
Has anyone else experienced a soundtrack changing like this?

Posted by Rob Young. (Member # 131) on July 11, 2016, 07:25 AM:

Phil, strange one...think step by step elimination of possible causes is the way to go.

Firstly, have the tested the films stored near it on your various projectors, just to rule out the possibility of accidental damage from a magnetic source, say a loudspeaker close by?

Did you treat or clean the film with anything? If the magnetic track looks good, the film hasn't warped has it?

Posted by Phil Slater (Member # 2388) on July 11, 2016, 07:35 AM:

Rob,
It hasn't been stored near projectors or speakers. Its possible that it has been accidentally placed near a speaker but not for more than a few hours. Would this be enough to cause it? The film was cleaned with Filmguard when I first got it, and there is no warping of the film. The print is in very good condition.

Posted by Mathew James (Member # 4581) on July 11, 2016, 07:52 AM:

Is it possible that the magnetic strip has lost some magnetism due to age in the areas you mention, thus when you re-recorded the sound, there was not enough on the strip in those parts to 're-write' to?
I have one reel that does similar to this, but it came this way to me so i don't know the films history, but i had always suspected it was a damage mag strip since i keep my heads clean as well...
Strange regardless!

Posted by Rob Young. (Member # 131) on July 11, 2016, 08:17 AM:

"Is it possible that the magnetic strip has lost some magnetism due to age in the areas you mention, thus when you re-recorded the sound, there was not enough on the strip in those parts to 're-write' to?"

With respect, Matthew, I think that is unlikely, especially as the soundtrack played back fine after re-recording.

Phil, placement near an unshielded loudspeaker can always potentially cause damage to magnetic media, although I won't have thought so precise as the drop-out you are experiencing.

If all your other films are ok, and the print definitely exhibits the same fault on several projectors, then another re-recording may be the way go in order to test the stripe.

Perhaps run the whole print through your Goko with just a test tone recording first? That will save you the bother of syncing sound and reveal the condition of the sound stripe before doing a full sync re-record?

EDIT: Just a thought, but maybe give the print a dry clean with a soft 100% cotton cloth, just to remove any potential over appliance of Filmguard which may have "pooled". [Smile]

Posted by Mathew James (Member # 4581) on July 11, 2016, 08:27 AM:

I agree with Rob. I didn't see that it ran good a few times first. The magnetic stripe must be intact.
Like i say, I have 1 film like this, Little Rascals, Man from Borneo(i have 2 copies). Does this exact thing you mention Phil and drives me crazy..I hope you figure it out.... If it is indeed not the strip, then re-recording should fix the issue!

Posted by Phil Slater (Member # 2388) on July 11, 2016, 08:38 AM:

Good advice guys, I think re-recording may be my only chance of salvaging this film. I think I must have had it too close to a speaker or something. I'll be sure to keep them well apart in the future.

Posted by Rob Young. (Member # 131) on July 11, 2016, 08:59 AM:

Phil, give it a clean first just in case, but, yes magnetic media and unshielded sources of magnetism don't mix well!

Although, of course, the good (er..encouraging) news is that although the recording may have been damaged, the actual stripe hasn't, so as long as you still have a master, you'll be ok.

If it were me (and I'm admittedly pedantic about these things), but I think it's always best to eliminate causes of problems in order...

I'd also run a test film, say 50ft or so of clean "scrap film" with decent stripe through the Goko, with a steady and constant test tone recording, then play it back on the Goko and all of your projectors a couple of times, just to eliminate the possibility of any potential soundtrack damage by any of them.

Don't think that is likely, but always best to be sure and it won't take long...all part of this wonderful hobby!

Then, if all is well, as I say, run a test tone recording on your film and try it on the projectors to be sure the magnetic stripe is ok before bothering with a full sync re-record.

Good luck!

And if the original re-recording gave good results, you have every chance of saving the film.

Posted by Phil Slater (Member # 2388) on July 11, 2016, 12:29 PM:

I have re-recorded it today and it sounds good.

Posted by Osi Osgood (Member # 424) on July 11, 2016, 01:00 PM:

Phil, this is only guesswork on my part, but i do remember years ago, when wanting to erase a magnetic tape, some people had devices that you would just wave the tape in front of, (a demagnetizer? I really don't know) ...

At any rate, it would completely wipe clean the magnetic soundtrack, making for brand new recordings without any "ghosting" from earlier recordings.

The reason why I pose this, is ... is there any chance that you film might have been stored near something that may have acted as a potential "demagnetizer"?

I know it's a longshot, but It's a thought.

OSI

Posted by Gary Crawford (Member # 67) on July 11, 2016, 02:48 PM:

In my experience almost anything electrical in close contact with magnetic tracks can produce what was described. Motors, speakers, and even cell phones can produce partial erasures at times.

Also, the playback heads of the projector can sometimes become magnetized themselves, but that usually just lowers volume evenly over the whole track, hitting the high frequencies first and increasing the amount of hiss.

Posted by Raleigh M. Christopher (Member # 5209) on July 11, 2016, 04:24 PM:

quote:
Phil, this is only guesswork on my part, but i do remember years ago, when wanting to erase a magnetic tape, some people had devices that you would just wave the tape in front of, (a demagnetizer? I really don't know) ...

It's called a degausser.

Posted by Brian Fretwell (Member # 4302) on July 12, 2016, 03:11 AM:

I would have thought that if it was damage by the spool being stored near a magnet it wouldn't be a regular 5 seconds between sound dips as the film at the centre of the reel would have less film per turn. If the rate of sound dip speeds up as the film progresses it would be more likely to be due to that.

Posted by Phil Murat (Member # 5148) on July 12, 2016, 12:44 PM:

Hi,

I reported same phenomenon (sound drops) for some HEFA prints.......
Checking the print with a magnifying glass, it appears the quality of the main track was poor: Density of the track was fluctuating along the print.
Also, after playing these movies, a lot of "Brown" particles apeared on the pinch roller and on other guiding parts.
Sound tracks for these films were made with "Mag Liquid" technic instead of real self adhesive tape .
So, simply avoid these kind of prints as possible....

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