Print through

So you have just made a technically perfect recording of a piece of music with
true beauty and meaning. You take the tape off the machine and put it carefully
on the shelf ready for mixing tomorrow. Tomorrow comes and you play the tape
- it isn’t at all like you remember it, all the loud percussive sounds
have strange echoes, not only after the initial sound but before it too. This
is print through. Particularly during the first twenty-four hours after a recording
is made, the magnetic force of each loud sound will seep through perhaps two
or three layers of tape in both directions causing pre- and post-echoes. Other
than fast winding the tape a couple of times in each direction (which doesn’t
make very much improvement) there is no safe cure for print through. It has
messed up your recording forever. Two methods of reducing the effects of print
through are to use noise reduction and to store the tape tail out. Although
there will physically be print through on a digital tape, it won’t affect
playback in the slightest. Score so far: Digital 4, Analogue nil.

Head alignment

All analogue recorders are aligned so that the gaps of the record and playback
heads are precisely at 90 degrees to the direction of tape travel. If this statement
were true, then head alignment wouldn’t be a problem. In practice recordings
are made on machines with wrongly aligned heads which then will not play correctly
on a properly aligned recorder. This causes a loss of high frequencies and has
a damaging effect on the stereo image. Although the alignment of digital heads
is important, a small deviation wouldn’t make any difference at all to
the sound, and since the head alignment isn’t user adjustable no one can
get it wrong apart from the manufacturers who really ought know what they are
doing!

Gap scatter

Even if the heads of a multitrack recorder are aligned as well as it is possible
to align them, there is still the manufacturing defect known as gap scatter.
This is when the gaps of the individual record or playback elements of the head
are not all at exactly the same angle. This makes it impossible to align the
head properly for all the tracks. In rotary head recorders of all types, including
ADAT, there can be no gap scatter.

Line up

Analogue recorders are very moody. Their performance changes with the state
of wear, type of tape, the weather and any of innumerable variables. An essential
task involved in operating an analogue recorder is line up. At the small studio
level, line up will be performed rarely but (hopefully) regularly. Major studios
consider line up as important as tuning a piano. You wouldn’t be happy
if you were paying several hundred pounds for a day in the studio and find that
the piano is out of tune. You also wouldn’t be happy if the recorders were
not working at the peak of their performance. Digital recorders do need lining
up, but this is a job for specialist engineers, and as long as they are running
within specifications the tape will record and play back perfectly.