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Old September 6th, 2015, 01:55 PM   #1
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damaged VHS tape?

Just finishing up on my archival-video documentary.

One of the tapes was damaged before or during recapture:

http://www.teachingdrum.org/adjul/tape5test.wav
(Note: the image is totally fine for this capture)

All the audio on the tape sounds like this. I had taken the VHS tape apart and removed a small piece of plastic that was rattling around in the wheel. I didn't quite know what I was doing taking it apart, so I may have done the damage then.

Either way, none of the other 10 tapes gives me audio static like this one, and this was one of the tapes I could've really used the recaptured audio on. Any ideas? I posted this to the audacity guys too to see if it was salvagable. Looking at it in RX4 it's got vertical lines running all through it with no regularity, and passing right through the actual dialogue.

If there's a way I could clean the tape too that might work?

P.S. I can't recommend the ADVC highly enough. Not only cleaned up the picture on these vids (restored a lot of over-contrasty image, and did wonders with out-of-control VHS wobble) but also raised my audio ceiling by lowering the levels across the board; the first tapes would clip super easily, which is why I would really like the audio from this tape.
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Old September 6th, 2015, 09:51 PM   #2
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Re: damaged VHS tape?

That's pretty nasty. Not only all the static, but power line hum, lots of LF "thumping" and some mid-HF "swooshing." (It reminds me of an FM RF link that is not in full quieting. But a stereo RF link? Very strange! If I wanted to venture a completely wild guess, I would say it was a broadcast-band FM wireless mic, picked up on a consumer receiver operating in stereo mode.) And yet there is absolutely no audio above 10 kHz ... the whole thing has gone through a steep LPF at some point.

I think that static was recorded along with the rest of the audio, not introduced by something (e.g. a piece of plastic) later. The audio is stereo, and the static is not the same on the two channels.

I did a quick repair, then combined the two channels (I don't see any good reason to have the voice bouncing around on a stereo pair). Result attached.
Attached Files
File Type: wav tape5test-repair01.wav (985.4 KB, 22 views)
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Old September 7th, 2015, 09:20 AM   #3
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Re: damaged VHS tape?

Wow, Greg. That's much better than I've been able to do.

Did you run noise removal on it, or what? What program/techniques?

If I could replicate your technique on the whole tape I'd be happy enough, otherwise I'll be removing the tape and putting it in a new cassette to recapture; hoping that the cassette itself was the issue.
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Old September 7th, 2015, 09:17 PM   #4
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Re: damaged VHS tape?

I ran two different audio processing programs, and applied a few different filters (at least one of which is very old and no longer available ... I think the company went belly-up). Not easy, but still easier than trying to fix it by hand.

As I said, I strongly believe that the noise is recorded on the tape, and was not generated by some piece of plastic during playback. I guess the easiest way to determine that is to load the tape into a new shell and try playing it again.

That audio is very strange for many reasons (as I listed above) and it would be interesting to know the exact history of how it was recorded, using what equipment. e.g. why does the narration (which should be mono) wander randomly between the two stereo channels? etc. etc.
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Old September 7th, 2015, 11:22 PM   #5
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Re: damaged VHS tape?

LOL. So typical of these forums. Somebody posts about a problem with a sound clip attached as a sample ... and the reply has the clip fixed. And they beat me to it this time.

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Old September 8th, 2015, 05:40 AM   #6
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Re: damaged VHS tape?

Linear track would usually be mono, and bandwidth limited below 10K.
At one time there was linear track stereo.
That could suffer some of the mentioned issues.

Sometimes trying different VHS player may find one that works better than others with a give tape
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Old September 8th, 2015, 10:54 AM   #7
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Re: damaged VHS tape?

Greg,
I'm not totally sure how the audio came about. I was not present at the filming 10+ years ago.

The video was taken with a camcorder, and from what I could tell, he was using a shotgun mounted to the cam. I think so because when people further away from the cam talked, their voices would be lower, until he would manually turn up the gain on the camera.

There were also external mics placed in the middle of the circle talking. I don't think these were added to the mix; I think they were some of the participants (it was a workshop that was filmed) personal recorders. But, there is a chance that he had a wireless link to one or ore of these recorder/mics placed in the center -- which would maybe account for bouncing channels (but I doubt it?)

I've contacted two of the participants who supposedly owned the audio recordings, but was never able to get them to follow through on mailing me the cassettes to digitize.

And it sounds like your audio wiping skills are out of my league! I mainly edit with RX4, and my beginner attempts at using its noise removal does nothing close to what you've done here. Guess I'll just use the old version of the tape capture before the tape was damaged - that is if re-shelling and re-recording doesn't help.
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Old September 8th, 2015, 03:44 PM   #8
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Re: damaged VHS tape?

Are you saying that you have an earlier audio transfer that is free from all the noise? More mystery ...
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Old September 8th, 2015, 05:31 PM   #9
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Re: damaged VHS tape?

FM rotary head audio that has an alignment issue between the replay machine and the record machine. If there is a switch to replace the hi-fi audio with longitudinal sound, it might solve the problem. Could also be when the recording was made, the heads were a little dirty. The hifi audio was recorded under the video and this kind of noise was reasonably common when it wasn't tracked properly, as in the head switching a tad off.Perhaps worth giving the heads a proper clean, and checking the tape surface to see if you can see grazing.
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Old September 8th, 2015, 06:22 PM   #10
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Re: damaged VHS tape?

Greg, no. Someone had captured the tapes previously to me with a VHS-USB cheapo recording dongle. The tape became damaged (dropped) between that capture (which had undamaged audio but still PLENTY of noise) and when I recorded mine on the AVDC.
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