Just playing a tape probably does not reduce it's quality in a measureable amount. If the tape deck is not demagged then playing the tape may cause partial erasure which might be hard to distinguish from self erasure. The pack if you leave it tails out is prettier and probably excludes atmospheric oxygen better than if you rewind it at high speed.īaking a tape probably increases some self erasure though it may not be enough to be audible. There may also be effects from whether it was stored "tails out" ie played and not rewound at high speed. I think it also depends on how long it has been since a tape has been rolled and how tightly packed it was at the time. I am told by a recording engineer friend that TDK tape does not have this problem but that Ampex Grand Master does. I believe this is the problem for which they bake the tapes. However when they get to be 50 years old atmospheric oxygen may have contributed to additional polymerization of the backing layer which may make it stiffer and brittle and more prone to snap if the transport buttons are not pressed very judiciously and the transport brakes not adjusted correctly.Īnother backing layer problem is sticking together. These are selected to be stiff so as not to stretch when on a tape transport. The mechanical backing layer of tape is a thin plastic. If a tape is shedding oxide badly it can mess up playback machines which certainly should be cleaned and demagnetized before playing back a valuable master tape. It the piece that falls off is big enough there is "data loss" or possibly S/N degradation. One of these is adhesion failure which causes the magnetic oxide to fall off the tape. There are also problems of the tape backing layer. The above are problems of the magnetic layer. I think this is a statistical process of magnetic domains (correct me if I am misteaken) and iirc affects the high frequencies more. Then there is the phenomenon of self erasure. (Just as an aside it seems to me that this would be something that would be a candidate for some software writing hotshot to figure out a correction process for if it hasn't been done already) LPs can have a similar phenom of adjacent groove cross talk but I don't think that happens unless its a really old cutting. It can sometimes be heard as a pre or post echo, sometimes even on LPs. This is where the recording on one layer of tape probably at a higher level imposes itself and becomes audible on an adjacent layer of tape. and maybe more distortion (very evident in my favorit Jimi Hendrix tune in spite of being recorded at Electric Ladyland)Įven absent the above if a reel to reel master tape is thirty of forty (or even more!) years old it can suffer from several things that decrease its fidelity. when digitized there is only 10 or 12 bits of dynamic range. A lot of very good questions.įirst of all they were recorded "back in the day" which imposes some limitation on them by virtue of the loose specifications in some recording studios. I don't claim any high degree of expertise but there are lots of different things that happen to master tapes. My question to the experts is what is the “science” behind the deterioration of master tapes over time? How much fidelity is lost when a “safety copy” is made as compared to the original? What about “baking” of tapes I read about, if tapes have to be baked do they lose fidelity and how much? Do master tapes lose fidelity every time they are played and if so, how much? Do master tapes lose fidelity over time just sitting in a box? I have also read “early” tapes from the 50’s and 60’s hold up better than newer formulations in the late 60’s and 70’s… any truth to that? Finally, I have read that aligning the heads to a master tape made on a different machine than it was originally made on creates issues… can this be quantified? To me it seems that while these claims are in general overstated in some cases they do seem to have some merit (for example I have an original Jimi Hendrix LP which sounds better to me when level matched ABX against more recent “re-issues” CD’s or LP’s of the same). Some people claim original LP’s and even CD’s made from “fresh” master tapes decades ago can not be equaled today due to damaged or lost master tapes. There is a lot of discussion on the internet about “original master tapes” of music from the past and their condition and availability as these tapes are used for “re-issues”, “re-masters”, and “re-mixes”.
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