On 27/08/08, Charles Lawson wrote:
> "Michael H. Gray" <[log in to unmask]> writes:
>> I'm curious to know how master tapes 'deteriorate' Is it in the
>> physical carrier or in the magnetic signal?
> Both. Depending on tape stock, materials and storage, the tape itself
> may degenerate over time causing drop-outs or worse. (There have been
> many extensive discussions of the hydrolysis problem associated with
> tapes from the 70s and 80s, for example.)
> Also, magnetic tape recording itself is inherently unstable. Those
> magnetic domains don't just sit there for all eternity in the same
> configuration as when they were recorded. They are easily influenced
> by temperature and external magnetic fields (including that of Earth
> itself) and will tend to randomize over time. If the tape was recorded
> at a high level, layers of audio will print through from one to
> another and this problem tends to get worse the longer the tape is
> sitting there. High-level recordings also have a greater tendency to
> exhibit increasing distortion over time.
> It goes on an on...
> Some references here:
> and there are lots more.
> People like Richard Hess have spent substantial chunks of their lives
> dealing with these issues and can give more detailed explanations than
> I have time for today, alas. It's all very interesting and can take
> down to quantum mechanics, if you like! (Aside from being an expert,
> Richard is also a really nice guy! If you need a tape transferred, go
> to him.)
Yet in spite of all these problems, it is astonishing what good sound
Universal, Sony and EMI can extract from 1950s tapes.
Presumably these majors have good or fairly good storage, which isn't
always the case.
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