Though a topic more likely to be discussed and reviewed in a
professional-audio magazine than in a hi-fi magazine does the microphone truly
represent the final frontier in our pursuit of high fidelity sound?
By: Ringo Bones
During the Golden Age of Stereo, all audio recording
equipment – even one’s destined for domestic use – were all equipped with
microphone inputs to facilitate do-it-yourself recording for the audio
enthusiast. And as time went on – as in around the 1980s, every audio recording
gear destined for consumer/ domestic use – like hi-fi cassette tape decks and
later recordable CD decks, mini disc, DCC and even DATs – seem to forego the
inclusion of a microphone input as a feature. Given that virtually all music
and audio recording that we will eventually be listening to our home audio gear
was first captured by microphones, does the microphone truly represent the
final frontier in our quest for high fidelity sound that’s indistinguishable from
the one that occurs naturally? Or does existing microphone technology actually
“hear” music the way our ears do?
As stated by Stereophile magazine editor John Atkinson
during the recording of their Encore CD in the January 1998 issue of their
magazine, there is absolutely nothing natural about recording an acoustic event
– let alone making it sound as natural as possible. As a testament as being the
engineer of the scores of recordings commissioned and sold in Stereophile,
Atkinson – and probably every other experienced recording engineer like him – is
ready to admit that microphones don’t “hear” music in the same way that our
ears do. And far from being natural, are actually chosen for their sound during
sound recording / music recording.
As an example in the live Classical Music recording session world
– if one is recording violins, the polar distribution of the radiated power
along the axis of the violins’ top plates is such that it will overwhelm any
other sounds the microphones are intended to record – so one is forced to
record from any position but one along that axis. Most recording engineers
choose to raise their microphones well above it since that solves other
problems relating to the way microphones perceive – or “hear” - the musical
instruments on a performing stage.
To cite Atkinson’s another example: Simply by using spaced
omni-directional microphones, a recording engineer can create an illusion of
spaciousness that may not truly exist in the recording venue. The distance
between the microphones affects lateral time cues on the recording; the
perception of spaciousness can be profoundly influenced simply by varying that
spacing.
The rather novel microphone setup known for its unrivaled
naturalness in capturing the sound of the recording venue used by John Atkinson
on all of the Stereophile live music recordings made in the 1990s are compared to
“multi-way speakers” by other recording engineers since the microphone setup is
optimized to pickup either the lower or the upper part of the audible spectrum.
They consist of two outrigger B&K omnis that were hung by their leads from
the ceiling 8-feet from the stage and 13-feet from the floor. A central pair of
B&K cardioid microphones was mounted on a stereo bar, and hung by their
leads from the center of the ceiling 11-feet above the level of the stage and
the same 8-feet back the omnis. The two cardioids were used in what is called
an ORTF configuration: the mikes angled at 115-degrees, their tips spaced about
7-feet apart. The ORTF microphone technique was developed in France and gives a
nicely defined soundstage, but the tonal balance lacks low-frequency bloom. The
spaced omnis, on the other hand, give a wonderful sense of bloom and very
accurate tonal color, but have mediocre stereo imaging. Such rather elaborate
setup results in a Classical Music recording that has the sound-staging of a
minimally-miked recording with a tonal naturalness of a multi-miked recording.
Unfortunately, such recording set-up that works very well in
the Classical Music recording world doesn’t work very well in the heavy metal /
rock world – which requires quite a different microphone, recording and mixing set-up altogether. One of the
problems is purely technical: To create a clean heavy metal / rock recording
with excruciatingly loud electric guitars is extremely difficult when the
guitar amps, the drum kit, and the vocalist via a loud PA system used as a
monitor are all going at the same time in the same room / acoustically
unisolated recording venue.
Because the sound of
the instruments leaks into the microphones used to record the sounds of the
other instruments, a muddy sound is the result. Given that most bootleg heavy
metal / rock concert recordings made from the 1970s and the 1980s have their
sound captured by a microphone set up that resembles the one intended for minimally
miked Classical Music recording, most bootleg heavy metal / rock recordings
tend to be unbearably muddy sounding in comparison to their studio recorded
counterparts – or a live concert recording “overseen” by a skillful FOH mixing
engineer. In conclusion, we still need skillful live music recording engineers / FOH
mixing engineers to make existing microphone technology sound as natural as the
way our own two ears hear music – whether Classical or heavy metal rock.
