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Introduction
To High Definition Surround
by Brad Miller
Many
of the most compelling recorded performances of our time are now
available from the HDS label, an acronym for our "High Definition
Surround" trademark. Each title is a 4.1 or 5.1 mix from an
original studio and/or location recording. The discrete (separate)
multichannel program is encoded in the digital data stream of this
compact disc with DTS Digital Surround technology. This and other
DTS encoded CDs are playable by connecting the digital output of
your CD, LD, or DVD player to any control device that contains DTS
5.1 digital decoding capability.
It is recommended
that you employ a minimum of four matched full range loudspeakers;
one pair for front left and right and one pair for left and right
surround. A center channel loudspeaker that at the minimum matches
the timbre of the front loudspeaker pair if and when included for
5.1 movies as well as music, should be slightly recessed if possible,
as its physical position relates to the front left and right loudspeakers.
This will create an arc and helps to eliminate center channel build
up, often referred to as the "closeline effect", which
can degrade the depth and balance of the frontal soundstage image.
Further, in order to reproduce the lowest octave smoothly, a subwoofer
is also recommended. In fact, a pair of subwoofers placed between
your left and right loudspeakers maintains room coherence, even
though each is reproducing a mono channel source, ie., .1 LFE channel.
Regardless
of how or where this recording was made, a vital production step
called "The Mix" is undertaken. Multi-track (8, 16,
24, 32, 48 and so on) original recording session masters are mixed
down (combined) into descrete multichannel music surround mixes,
with equalization, source levels and balance of the entire soundfield
adjusted and finalized. What is important for you to know is how
"The Mix" is monitored by the professional recording
team, so that you might approximate (or replicate) this scene
within your own listening environment.
"The
Mix" employed matched full range loudspeakers with equal
amounts of amplification applied to each, including the surround
speakers. They may have been nearfield or midfield monitors,
plus subwoofer(s), depending upon the size of the recording
studio control room. No surrounds were ever placed on the side
walls, not were dipoles employed. Diffusion of the soundfield
as expounded by some, is a creative decision that is addressed
by the professional record/mix team, and should not be impacted
after the fact by loudspeaker design or outdated theorums.
In the
most general of terms, the four corner (primary) full range
and matched loudspeakers were toed in about 45, and exhibit
a dispersion of approximately 90, in order to create a symmetrical
360 auditory plane. The full range matched center loudspeaker
(when used) occupies a recessed location dead ahead. This
allows for each of the primary (4 or 5) full range matched
loudspeakers to be equidistant from the engineer/mixer position
at the mixing desk. However, if the mix maintains phase and
frequency coherence, one may enjoy a multichannel music surround
mix from many different locations. Try listening outside of
the direct soundfield reproducing space for yet another revealing
experience!
The .1
channel in a 5.1 (6-channel mix) refers to LFE (low frequency
effects). In motion picture soundtracks, impact effects
reside here, like explosions and dinosaurs with extended
low frequency content. In music mixes, the .1 LFE channel
allows for the smooth reproduction of the lowest octave,
and you will find it in use even if the original mix was
for example, a 4.0 master from the 1970's era. The .1 LFE
channel in these instances will be "derived" from
the original 4.0 mix. The selection of the number of channels
engaged for a mix, whether it be 4.0, 4.1, 5.0 or 5.1 (6),
is a creative decision of the moment. Each is valid dependent
upon the decisions made by the professional recording team,
and the tools available to them at the time of the mix.
As
you can see, nothing in these general guidelines or the
explanation thereof alters the enjoyment of your 5.1 discrete
digitai audio system for home theater, car surround or
for the cinemas throughout the world. We in fact now have
one uniform reproduction standard for all! And, you will
experience an unprecedented musical journey from this
High Definition Surround compact disc that was heretofore
unattainable, given the limitations of 2-channel stereo!
Space - the final frontier - has begun!
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