On 18/12/2010 23:25, Dave Plowman (News) wrote:

wrote:
Keith G wrote:
"Dave Plowman wrote:
Keith wrote:

Just don't buy it on magnetic tape or the silence will 'print
through' from the next layer of tape down if it is stored long
enough!

Not a problem with digital tape. ;-)

Is that so? I wouldn't have thought it would be any different to
analogue...??

In principle, it isn't. The magnetic signal can be degraded by being
reduced in amplitude, whether in analogue or digital.

I've not noticed an analogue tape which suffers from print through being
reduced in level. The top end may be slightly lower than when recorded,
though.

The effect from analogue print-through in audio is well-known. It is
manifested as a post-or pre-echo of the signal as the tape next to the bit
with the original signal passes the replay head. Pre-echo has been known to
transfer onto vinyl disc when transferred from a master tape with high-level
signal which has not been stored "tail out" (post-echo being seen as better
than pre-echo). You could hear a ghostly image of the intro a second or so
before the "proper" start.

But the digital effect would not be to turn down the volume (as with
analogue tape). It would be manifested as a perfect signal until the
degradation reached a certain point, when the signal would become
incoherent. Just as happens with a TV aerial being used to recieve and
transfer digital transmission into a digital TV. Or like with a CD with
a fingerprint of strawberry jam on it.

The sort of level of print through means in practice digital systems
ignore it. Or that's my experience.

I don't have much experience with digital tape. I do have a nowadays-unused
DCC machine (and about four DCC cassettes) but never owned a DAT recorder. I
do have a digital tape video-cam, but can't say that I've either used it much
or noticed any problems.