multitrack tape degradation

  • Thread starter Thread starter christiandaelemans
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christiandaelemans

christiandaelemans

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hey y’all. i have a question that i’ve poked around about online but never got a straight answer or discussion about, maybe because it’s so obvious. but, especially for those who used to work with tape in the 70s, 80s and 90s, did you ever worry about degrading the multitrack tapes during mixing sessions??

i ask because, after probably upwards of 60 passes (either while mixing or doing overdubs) on each of my songs recorded onto 8 track 1/2” tape, i’ve began considering the consequences of rewinding so many times. not that things sound dull, but i’ve heard the stories of fleetwood mac’s “rumors” drum sound debacle.

unless i’m misunderstanding the old process, the old school studios had to rewind every time they wanted to run back a song while mixing, right? of course, we’re talking about pros who can get a good mix within a few hours, but that’s still wear and tear. add in the stories of the 5 person mix-downs with choreographed fader dances, and that sounds like a learned performance which would have a lot of trial and error (rewinding).

i myself am going to get a replacement 8 input interface in the next few days so i can digitize the multi tracks and rewind infinitely as i mix through my console and get things really tight without worrying about the tape. but i know for sure that this kind of technology didn’t exist for quite some time.
 
addendum: i am using new ATR master tape, probably manufactured over a year ago and only been used by me for a couple months. so my personal work doesn’t involve any type of sticky shed fear or whatever else may come from using old tape.
 
well, back then I never even thought about tape in this way. I went to great lengths not to mechanically crunch it. Brakes often got out of adjustment so hitting play while rewinding near the end when the spools were going fast was a bit risky when it snatched, but I never ever worried about wearing it. That said, my Ferrograph at the time did get magnetised quite easily and I think each pass probably dropped the level a tiny bit, looking back - but it was never a problem I remember. Now, with my aging machines, and tape at crazy prices I find I am soooo much more careful, and actually go to play, from rewind, using stop! If you demagnetise often I suspect you will be fine, but that crap that you clean off the heads and guides comes from the tape, so you can actually see how much oxide is coming off?
 
rob aylestone said:
well, back then I never even thought about tape in this way. I went to great lengths not to mechanically crunch it. Brakes often got out of adjustment so hitting play while rewinding near the end when the spools were going fast was a bit risky when it snatched, but I never ever worried about wearing it. That said, my Ferrograph at the time did get magnetised quite easily and I think each pass probably dropped the level a tiny bit, looking back - but it was never a problem I remember. Now, with my aging machines, and tape at crazy prices I find I am soooo much more careful, and actually go to play, from rewind, using stop! If you demagnetise often I suspect you will be fine, but that crap that you clean off the heads and guides comes from the tape, so you can actually see how much oxide is coming off?
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i have never demagged my machine MYSELF, however when i bought it from the folks who serviced it, they did demag the heads. think of my machine as 5 months without demagnetizing, as i went straight into album production without noodling with recording.

if im being honest, since i dont have any issues that i see attributed to magnetized heads, and i have seen a bit of debate as to whether or not its necessary when recording and erasing frequently, i just haven’t done it. in fact, i’m pretty worried i’ll somehow cause an issue if i attempt to demagnetize it.

as a young man who dropped some sizable dough on this analog studio set up, its a pretty scary thing to say “yeah just wave that EXTREMELY POWERFUL electro magnetic wand around your magnetic tape machine. oh and yeah you WILL fry it if you don’t do this one thing right. but yeah just go ahead and get real close to those heads. yup those expensive and essential tape heads. don’t stay there too long or you WILL brick the whole thing.”
 
First rule of reel to reels. Buy isopropyl alcohol in a big container, plenty of cotton buds and lint free cloths and a demagnetiser. The heads and some other parts in the tape path get magnetised every time the tape passes through. HF response suffers and worse, magnetised parts partially erase the tape each time it passes the heads, reducing the overall level a tiny bit. Back in those days, I demagged once a week, but in many places, you did alignment everyday and demagnetising was also high on the list.

You won't fry it, but you have to get the technique right - it's easy though. Almost touch the probe to the head (or guide). Apply power to the tool and slowly withdraw till you are across the room, then switch off. Done. If you mess up and switch the power off when close to the heads, then you will magnetise them. You just do it again, properly. You don't wave it around, you just go in very close and withdraw. In most cases, if there are three heads, all of which are designed to convert electricity into magnetism, you can just do each one, individually. I had two guides, one each side. My boss advised doing them too, although not as often as the heads. I don't know for certain if they were even made of metal that could be magnetised, but I did them.

If you accidentally magnetise them by doing it wrong, you just do it again. You actually never know - you don't brick anything. You just make partial erasure more likely with each cycle, and the sound gets a bit dull.

Your query was about the dangers of repeated playing - so if you are worried about that, demagnetising is part of the deal. What you describe is a bit like running a performance car on dodgy fuel and just driving slowly so you don't hear the knocking.
 
I never worried about tapes losing anything. I have a demagnetiser, and would pull it out after a couple of months. As Rob said, cleaning with Isopropyl would happen weekly.

I seriously doubt that you are wearing the tape down unless you're doing 6-8 hour sessions every day for months. The Fleetwood Mac stories are unique circumstances.

christiandaelemans said:
“yeah just wave that EXTREMELY POWERFUL electro magnetic wand around your magnetic tape machine. oh and yeah you WILL fry it if you don’t do this one thing right. but yeah just go ahead and get real close to those heads. yup those expensive and essential tape heads. don’t stay there too long or you WILL brick the whole thing.”
Click to expand...

Demagnetisers aren't massively powerful magnets. I have a bulk tape eraser that will clear off a tape. It will probably lift a 5 lb bucket! Head demagnetizers are nowhere close to that powerful. They work by creating an alternating magnetic field. As you move the point away from the head, the field strength gets slowly weaker, still alternating between N & S until you get it several feet away. At that point the field is gone and the recording head is essentially neutralized.

We used to bulk erase tapes at the radio station. Same process, and when you finish, you had a perfectly clean tape, ready for a new commercial or song.
 
maybe i should get a wand… about how many feet away is a good distance to make the demagnetization gradual? with regards to the tape, i’m still certainly going to be digitizing my multitracks and maybe even mixing down the stereo 2 buss WITH the digital stems rather than the tape.

that means my multi-track tape is probably only going to be spun one more big time for this album. that’s 1 pass of analog to digital into my computer, another pass from the computer into the mixer on playback, and then an additional overall pass of the whole mix from the analog mixer outputs into the computer as a completed song.

not too bad… right? the trade off between physically passing my tape across guides and tape heads… over and over and over… but man it makes me excited just thinking about being able to instantly get somewhere in a song while mixing.
 
We would just bring the demag in from a few feet away, move over all the metal parts, and then just swing your arm across your body. You can easily reach 3 or 4 ft before you turn it off. You don't need to walk across the room.
 
Yes, you can wear through the tape, but it takes an extreme amount of play to do that.

If you will be doing the sort of meticulous production that would cause the tape to wear out, it would make sense to just transfer the things that need the tape sound to digital after it's recorded.

On projects like this, we would make a slave tape for the rhythm section. The slave tape would be what the musicians would track to. Then, when it was time to mix, the pristine original tape would be used.

Again, this is DSOM, Rumors, Black Album sorts of productions. I've done a few of these in my life, but never in a home recording situation.
 
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