If the tape is reasonably short and clearly
audible there can normally be no justification for
allowing a transcript as well as playing the tape.
But there will be cases in which the aid of an
expert is reasonably necessary. For example, there
may be the use of a foreign language. Or
deficiencies in the recording may make it necessary
to play tapes more than once to enable a better
understanding, yet the sheer length of the tapes
may mean that inordinate time would be taken by
replaying them to the jury. In such cases, while
there should normally be at least one playing to
the jury, the evidence of an expert should be
admissible as an aid to the jury. He may be a
temporary expert in the sense that by repeated
listening to the tapes he has qualified himself ad
hoc. And we see no compelling reason why his
evidence should not take the form of production of
a transcript which can be admitted as an exhibit.
Whether the Judge allows the jury to have copies of
the transcript, as distinct from merely hearing it
read, must be a matter for his discretion in the
particular case, bearing in mind the requirements
of justice and any risk of unfairness to the
accused."