The Perils of Classical Recording
Reviewers of audio equipment use a lot of different music
in their tests, because pop tends to show up certain things, jazz other things, and so on.
Most would agree, however, that the subtlest shadings of audio performance are brought out
by what is loosely termed "classical" music. We have a few standbys that we use
all the time and they all have one thing in common: they are superbly recorded.
Sometimes that seems like a minor miracle, because
producing a pristine recording of classical music is often fraught with problems. In some
ways, pop producers have it easier because the studios where this sort of music is
typically recorded afford almost total control over the sound. In many popular recordings,
each instrument and voice is recorded separately, at different times, and tinkered with
until it is the way the producer wants it. It's not uncommon for a drum kit, say, to be
picked up by as many as a dozen microphones, and the final combination of all the sounds
is produced long after the individual recordings were made.
Classical music, on the other hand, involves recording all
the instruments at once, usually in the sort of acoustic environment appropriate for the
music: a concert hall, cathedral, or whatever. It's relatively rare for a classical
recording to be made in a pop-style studio, where extraneous noises can be tamed; in the
case of a 100-piece symphony orchestra, that's almost impossible. So although the producer
might well edit together bits of a number of separate "takes" to come up with a
flawless total performance, each such chunk is the result of all the appropriate musicians
playing together in a real space.
Some of the best classical recordings have taken a
minimalist approach that involves using only a single pair of microphones, suspended above
the conductor's podium. In theory, the conductor creates the balance from instrument to
instrument by means of careful rehearsal, and the mikes just pick up what he hears. Often
this system works very well, but not always.
The main difficulty seems to be that microphones don't
necessarily behave like ears. We have a very sophisticated way of processing what we hear
to filter out stuff that's inappropriate. When we're sitting in a concert hall
concentrating on the music, we may be oblivious to people rustling near us or the
underlying whirr of an air-conditioning system, but such noises are easily picked up by a
microphone, and once they are on tape, we can't filter them out.
In spite of the best efforts of the technicians, there are
loads of recordings where, if you listen closely, you can hear the distant rumble of
traffic outside the hall or subway trains under it. One way this can be avoided is to use
a lot of microphones close to the instruments; this is effective for eliminating such
intrusive noises, but it requires a very complex electronic mixing job, either while the
recording is being made or later.
And even if the hall is perfect, the conditions under which
the recording crew must work often militate against the best results. Most of the suitable
venues for classical music were never intended for recording, so the producers have to set
up shop in corridors or waiting rooms, sometimes far from the musicians themselves. And
often they must do their critical monitoring by means of headphones -- useful enough
devices in their place, but hardly adequate for making critical recording decisions.
Given all these factors, it's remarkable that so many fine
classical recordings exist.
...Ian G. Masters
ian@mastersonaudio.com
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