Contrary to some estimates, so called Audiophile CD's need not be
more expensive to produce than "ordinary" recordings.  However, it is
frequently more economical to create a multitrack recording with each
orchestral section having a dedicated microphone (frequently individual
instruments may be assigned a single microphone and separate track) in
order to facilitate proper balance in post-session mixdown to twin stereo
tracks...thereby saving time during the original recording when the
per-hour cost of musicians tends to be high.  For various reasons modern
recording techniques for Classical Music endeavor to achieve a pleasing
overall orchestral balance with as few microphones as possible to better
subjectively approximate the concert hall experience in the living room.
Classical sessions with as many as 48 channels available will use only
two mikes placed in a special array near the conductor for the principle
pickup.  This seems to achieve a more integrated sound.  Numerous
additional mikes are used only to "enhance" orchestral resources as
required in the final mix.  (Woodwind sections frequently do not reproduce
in a realistic manner without enhancement during recording.) Acoustical
balance has been the most important part of the recording art for 100 years
and remains so to this day.

Up until recently many engineers preferred to use high tech analog tape
recorders with special electronics to achieve highly valued audiophile
characteristics accepted by many listeners over the years.

Today, high definition digital recording processes with high sampling
rates (20 bits per sample) exceed the resolution of analog recording.  The
current 16 bit compact disk technical standard also limits the resolution
of CD.  Fortunately, a process by which the greater resolution available
from high bit rate master tapes can be selectively assigned to the more
critical mid range of hearing is centered primarily on 2000-3500 hertz.
This process is called "noise shaping" with marketing terms such as "4D
recording" and "super bit mapping" frequently applied.  (High resolution
digital copies of historic analog recordings successfully use these bit
map techniques as well.)

Other subjective characteristics employed when making so-called audiophile
CD's (i.e., type of microphone) are variably employed by record producers
to affect the final out come.  However, to accomplish audiophile
recordings, these disks need not necessarily cost more than routine
recording accept for the cost of high priced artists.

Bernard Gregoire
Hingham, MA