Track Restoration

[john]

Hey

Anyone got any tips on track restoration? Recommendations for any automated tools?

Currently for me it's a mix of VST filters and manual treatment via Wavelab.

Cheers

John

[Roflcopter]

Adobe Audition has a few cool toolies. Other than more expensive solutions even... dunno. That software easily goes into the thousands.

What kind of track is it? Is it poorly recorded, or really damaged?

[john]

Analog recordings from cassette tapes. Mix downs from early 4 track recording on a porta studio in the mid 80s. Degradation in sound is purely down to time and a little damage from one of the players that damaged the tape edge.

Tracks will be sampled into my PC for treatment.

[Roflcopter]

Well, I'll be doing something similar soon, a whole box of 70's big tapes and cassettes from the 80's and nineties, all of unknown quality, but they want them digitized.

Waited actually until I got Audition. It will make a difference, I'm pretty sure already - that's one powerful program. I'll keep you posted, and maybe if you post a few samples in 24 bit wav I can have a crack at it too. We can then compare the diffs on different scope outputs, too - you really don't want to do this by ear alone anymore.

[john]

Hey

Yeah that was my feeling too. I'll post some up once I get them digitized

[Prometheus]

I've never tried this myself, not having had access to such facilities, but apparently baking the tapes in an incubator at around fifty five degrees celcius, flipping the tape every half hour for one to four hours can reverse the oxide shedding that occurs when moisture makes the oxide seperate from the plastic binder...

If the tape still sheds after baking, put it back in the oven...

Heat makes the binder more prone to stretching, so make sure you let the tape cool completely before playing it...

[Prometheus]

Here's a link to a guy who knows more about this than I do...

http://www.tangible-technology.com/tape/baking1.html

[Lazz]

I have baked and saved old 2 inch masters successfully a couple of times, using a regular domestic electric oven for the baking bit.

The saving process can give trouble. As the baked tape passes across the heads dumping the data onto hard disc, the acetate shreds and peels and piles up on the floor while you have your fingers crossed. It's quite exciting - because the irreperable material damage and loss of media means you only get one pass at the thing,

The reason I mention it is because I suspect that, being a 'closed' package, a cassette may be liable to cause more difficulties.

Maybe worthwhile figuring a way to run the old tape outside of its casing.

[Prometheus]

Or possibly take the tape out of the casing to bake it and replace it in the casing when the baking is done...

[Lazz]

Or possibly take the tape out of the casing to bake it and replace it in the casing when the baking is done...

Perhaps I'm communicating poorly - it's the post-baking bit I was expressing concern about.

And it's that very fact of being inside the casing which I envisioned as being problematic at that stage.

Baking re-adheres the layer containing the recorded info back to the tape again - but that's only a temporary fix - the next job is to run that re-stuck tape across some play-back heads (or whatever you call 'em) so you can transfer the data onto an appropriate computer gizmo. It's during that process of transferring from one medium to another (wot I called 'dumping') that I foresee some trouble that may need to be planned for. For running the baked tape over those heads causes the temporarily re-stuck surface to peel and break up and fall off into a pile of dessicated goo..... which is why I called it only a 'temporary' fix. In my imagination, if that gunk piles up inside a cassette casing you might not be able to get very far at all with the project. That's all. There must be a way of running it free of risky casing and avoid the problem - got any ideas, Prom ?

Come to that, baking cassettes while still inside their cases seems like asking for trouble anyway - I could be wrong - maybe the casing wouldn't collapse and melt at domestic temperatures - but it seems possible to an ignoramus like me. It also seems likely that someone somewhere already knows the answers.

As I say, my experience is limited to two restoration projects from 24 track masters - but afterwards, the masters are definitely toast - so you only have one chance. As far as I could make out, though, I was definitely getting an impression that this kind of tape deterioration as a significant problem was being maybe slightly exaggerated and possibly limited in fact only to particular styles and brands manufactured within a specific time-frame. The info I was getting was oftimes riddled with contradictory opinion. So I don't really know for sure, and I don't know where I put the articles we were using for reference at the time either.

What I do know for sure is that baking definitely does the re-adherence thing OK - problem is that you only get one chance at transferring - so you can't afford to f*ck-up (technical term), John.

Exciting stuff - But maybe you don't need to do any baking in the first place - maybe you should first test-transfer with an 'un-baked' similar age/model of cassette with stuff on it you can afford to say good-bye to - and if it works then we're all back to software solutions for cleaning up the sound - and I know zip about that either.

(I still have old multi-track master-tapes that I've been hoping to restore and transfer some day. The big problem for me now though is that nobody around here has the kit to run it anymore. Everything is digitized computerized outta-sightized. No more steam power.)

[john]

Hey

Interesting. I've ran tapes with almost a half casing before I would try baking on some comparable tapes of no real value first, see how I get on. Thanks guys!

As mentioned one of the problems is slightly chewed tape edge on one tape ate least. I doubt there is a physical process to repair that, but I was hoping there might be a digital filter to address this? I imagine it's quite a common tape issue and one with a definable signature.

keep the tips coming

Cheers

John

[Prometheus]

Baking re-adheres the layer containing the recorded info back to the tape again - but that's only a temporary fix - the next job is to run that re-stuck tape across some play-back heads (or whatever you call 'em) so you can transfer the data onto an appropriate computer gizmo. It's during that process of transferring from one medium to another (wot I called 'dumping') that I foresee some trouble that may need to be planned for. For running the baked tape over those heads causes the temporarily re-stuck surface to peel and break up and fall off into a pile of dessicated goo..... which is why I called it only a 'temporary' fix. In my imagination, if that gunk piles up inside a cassette casing you might not be able to get very far at all with the project. That's all. There must be a way of running it free of risky casing and avoid the problem - got any ideas, Prom ?

I've never actually tried taking a tape out of the cassette, sitting it on the rollers and just running it around the heads as you would with an old reel to reel, but my initial reaction is that it might or might not work, because from looking at a number of old cassette tapes from different manufacturers, they all run round little wheels at each side of the cassette that seem to be precisely in the same place no matter who built the cassette. Without them the tape could run at the wrong speed. I'm not sure about this. It could be worth experimenting on...

Apparently not all binders are born equal... If you try to restore a tape from the sixities, then it's acetate, and as you say, one run and the tape is history. By the seventies they were using a blend of polyester and mylar which was much more managable, because unlike acetate it does not become brittle.

What I would probably do is try baking a cassette with no value and run it through a tape player of no value. That way it'll become apparent whether the cassette case will cause problems or not. Since most cassette tapes were built in the eighties and nineties out of better plastic composites, it may be that they will not turn in to a gloop over the heads of the tape player and the inside of the cassette.

What I do know for sure is that baking definitely does the re-adherence thing OK - problem is that you only get one chance at transferring - so you can't afford to f*ck-up (technical term), John.

Absolutely. It would be prudent to transfer the tapes on to technology that is highly reliable that you have well in hand... Use a hard disk recorder or a miniDISC machine or something rather than PRO TOOLS. Even though PRO TOOLS might not have hanged on you in six months, sure as hell this is the time it would choose to play silly buggers...

If you can, use two recorders to capture the signal, and that way if anything happens to one of them, all is not lost...

Edited September 3, 2008 by Prometheus

[Roflcopter]

OK, my findings so far with digitising those tapes - they were in prime condition (the guy was the real stamp collector type, real neat), so no baking necessary.

And yes, for DIY audio repair under a 1000 bucks you want Audition, no doubt about it. It's a very powerful repair tool as well as many other things. It even has Photoshop like noise removal tools, like a lasso selection etc. Real cool.

http://www.youtube.com/watch?v=bqkfJqAPDTs

[john]

Hey

Thanks guys. Great replies so far.

Cheers

John

[Roflcopter]

Found my first weird tape of the batch, it had been rerecorded - and probably stored elsewhere temporarily, it looks real weird too, as if it's gone from round to 12-edged or something, as if the tape itself has lost some of its lateral tension, weakening it so it wants to fold inwards in places. Sounds reasonably OK still, amazingly, but runs off the spool at the end, since it refuses to spool nicely any longer, it takes up much more space on the 'to'-spool.

[Prometheus]

Something I've noticed that's pretty interesting is that I have a load of video tapes around the house that date back to the early eighties, and they are still perfectly watchable after twenty five years despite having been played lots. They have suffered in just about every case little or no noticable degradation...

And yet I have audio tapes that are only ten years old, dating back to the days before CD writers were affordable, and they have noticably degraded, especially the quality of the high frequencies...

What's so good about VHS tapes I wonder?

[Roflcopter]

Could just be the width of the tape - the fatter the better. Audio cassettes were like bottom feeding stuff compared to reel to reel, and VHS cassettes and players were a lot bigger and more advanced. Size does matter when it comes to tape. Think Studer.

I sussed the weird angling on that one tape - its the tape itself thats no longer flat, but curves up at the sides, so it won't fold nicely any longer. Wonder What I could do about that. This tape could be used for experimenting a bit, I think, it has no special content.

I also noticed that the tapes (also the OK ones), which were sealed in plastic, smelled pretty strongly of vinegar. I suspect some solvent evaporating slowly over time. If you don't keep your tapes wrapped in plastic you probably never notice this.

[Roflcopter]

Cool, no?

Dear sir,

I hope not to intrude, but this might be of some interest to you for archival purposes if nothing else.

I am currently processing a box of old tape recordings to digital format for someone, and on one of the tapes I found what appears to be a stereo recording of very reasonable quality of one of your concerts in the Tropenmuseum in Amsterdam in (most likely) the year 1968, although I looked it up and you played for 3 consecutive years there.

I think it was recorded from a radio broadcast, but again, it's of very decent quality and appears to be nearly an hour in length.

In case you have no other recordings of that event, and you would like a copy, I'd gladly sent you one or more CDs with the raw recordings from the tape, on my expenses, naturally.

Greetings,

Rob Hoogers

Amsterdam

Dear Mr. Rob Hoogers,

I am so very pleased to receive your email. I will be very grateful if you can send the recordings of my concert. Also if you can find more of my recordings of my performances during those years I will be very grateful to you.

Please let me know if I can do anything for you in return.

Wish you all the best and give you my blessings and greetings,

Imrat Khan

Website: www.imratkhan.com