In the year 2011:
sound has always promised
an exciting new music listening experience, but theres still
confusion about it which stands between us and realization of
its promises in our homes. Time for a Stereo Society geek-speak-free
Much of our extended-spatial musical options were identified in the early 1970s,
when we got all excited about the potential revolution with surround sound.
And this was before digital became ubiquitous, the compact disc
just a twinkle in the eye of progressive engineers. After reading this introduction,
its worth checking out the other three historical articles we
present, which are from this previous era but deal with the music capture and
its production values that still apply today. Notable is a
piece from the British Studio Sound magazine by renowned engineer/producer
Alan Parsons about the making of the quadraphonic version of Dark
Side Of The Moon in
the surround sound of the time (then usually called quadraphony). On
the classical side is a joint article by the producer and engineer on
an enormous Columbia Records classical surround recording, of Schoenbergs Gurrelieder.
A long essay written by Mike Thorne in 1974, Quadraphony
explores the musical possibilities of surround sound, with conclusions
still very relevant to us now.
The surround sound of the early
70s used four identical speakers, one in each corner, and at first sight
this is far more convenient for music and more easily integrated into
a living room. However, the surround we have now, to be described in critical
detail later, evolved from home theater sound systems and, although it
introduces its own compromises and needs two more speakers, in practice
it may be easier to integrate into a typical living room.
Back then, there were four methods of feeding four loudspeakers from
a vinyl analog disk. All of them were badly compromised, but the hardware
industry threw enormous resources behind them. The four heavyweights
in the ring all collapsed from exhaustion by 1976. Crucially, the public
disliked the standards battle being fought at their expense in their
own living rooms, and as a result simply didnt buy into the idea.
Its worth looking briefly at these defunct systems before moving
forward to today. With 20-20 hindsight, were entitled to be amazed
at the collective hysteria that made these cumbersome disks seem a commercial
possibility to the hardware industry. In fairness, those of us on the
production end who had heard the magic of surround really wanted to pass
it on and work in the medium, and these four primitive systems could
still sound very exciting.
Two of the systems, from CBS (SQ) and Sansui (QS, obviously to avoid confusion),
were so-called matrix-encoded systems. The vinyl record looked the same
as the standard stereo versions, except that four channels were folded
into two by an encoder. In making a record for quad(raphonic) release,
in the studio the four discrete audio channels were fed into an encoder
which adjusted the relative phase of its two output audio channels (in
a complicated way), which were then to be cut on a vinyl disk.
In the home, a decoder picked up the complex phase relationships and
produced four independent audio feeds. All well and good in the glossy
brochure, but in practice the sounds were not clearly placed and had
a disturbing tendency to wander around, sometimes during the short time
a snare drum sound would take to die out. If one instrument was playing
and another started up, you might hear the first one move somewhere else.
Nonetheless, the two matrix systems could give an exciting surround experience,
although it often had little connection to the luxurious spatial sound
that the engineers and producers had thrilled to in the control room.
get four channels out of two. As the physicists say, there are no free
In practice, the production team would monitor through four speakers
but after feeding the four original audio feeds to an encoder (down to
two channels) then through a decoder (back up to the four speakers) so
that a mix could be optimized for eventual domestic playback. This wasnt
so much fun for a production crew who could hear what was musically possible
but had a demonstration of the limitations of the system thrust at them
every time they mixed a quad record. Their reservations fed back to the
record companies, who started to get a queasy feeling in the pit of the
stomach as they were spending considerable sums to extend routine production
The other two systems, from JVC (CD-4) and Nippon Columbia (UD-4) added
an extra high-frequency disk component over the two front stereo channels,
so that the disks could be played either on a regular stereo or through
a demodulator that generated the extra two rear speaker feeds. This was
a considerable technical challenge. The vinyl needed to be harder, so
that the high frequencies didnt get worn away, and the stylus needed
to have much sharper edges so that it could pick up the extra high frequencies.
Instead of an elliptical shape, where the sharper curve would touch the
two groove walls, it was almost diamond-shaped. Naturally, these were
much harder to make and more likely to get chipped in use.
Quadraphony was completely dead by 1977. Most of its potential audience
had stayed home. However, around that time the cinema was beginning to
introduce surround sound widely. There had been several competing systems,
but the most prominent utilized six audio channels fed to multiple speakers
ranged around the theater. Another successful system, Dolby surround,
used a matrix encode/decode process like the defunct SQ and QS quadraphonic
disks, giving a good feeling of surround sound although without the control
of a discrete six-channel system.
The surround systems of the theater transferred to the home in the early
nineties, as households with both space and money installed what has become
a de facto standard, the 5.1 surround system. Ideally, there are
five speakers at front left, front center, front right, rear left and
rear right. The precise locations of the speakers has been subject to
debate, particularly when surround audio (DVD-Audio, then SACD) entered the publics
picture in 2000. Recently, a surround music producer even went as far
as insisting that the rear two speakers ideal music
position was different from that for home theater sound reproduction,
although I doubt that many enthusiasts will be heaving a couple of speakers
around every time they switch between recording and movie.
The .1 in 5.1 is a dedicated low-frequency speaker. Our two ears locate sounds by comparing their slightly different arrival times each side of our head. Low frequencies have a long wavelength (distance between repetitions) which may be too large a distance for our ears to distinguish (roughly, the space between our ears limits the wavelengths whose spatial origin we can detect). So this bass speaker can be anywhere in the room, although obviously
the closer you sit to it the more low frequencies you will experience.
Its output is considerably higher in power (10 dB) than the other five.
The low frequency signal is derived from the other channels.
By now, it must be clear that specifications and definitions of home
speaker placements belong to pedants and disconnected theoreticians.
Living rooms for human beings are not built to these specifications.
A generation ago, stereo magazines would still comment about the ideal
positioning of the speakers to deliver a smooth wall of stereo between
the two speakers. In practice, the ideal placement depends above all
on the room acoustics (and its shape) and on the speakers' dispersion,
the breadth of the sound beam coming from the speaker. If the dispersion
is small, the beam will be narrower and if you move sideways you will
be outside it and hear a correspondingly reduced contribution from that
Sonic accuracy has little resonance in the recording studio
or the home. Control rooms can sound wildly different, but engineers
and producers have learned to be flexible. Listening to a familiar recording
in an unfamiliar environment for ten minutes is most of what it takes
to recalibrate professional ears. There is an undefined standard that record
production tacitly acknowledges and that the nonprofessional listener knows intimately.
Anyone can notice when a recording is too dull or too harsh. In the home, the
most viable standard is whatever sounds the best, which is why we have tone controls
on the stereo. The object of all this technology is to have fun in enjoying music
as effectively as possible.
That said, the present convenience of home theater
playback still leaves much to be desired, and often falls very short
for music playback controls. A typical six-channel amplifier takes careful
setup, the engineers obviously intending that it be left alone with no
instant controls other than source selection and volume. Often, there
is no tone controls option to alter easily, frequency response only being
adjustable via remote menus applied to single groups of speakers rather
than having one knob that changes all. The comparison with user-unfriendliness
of the PC is immediate, and its to be hoped that a similar transition
to easier music functionality will eventually take place.
Its not necessary to arrange the speakers by the book to get very
satisfactory results. In many cases, breaking the rules might give you
a better musical sound. The center speaker is important in movies to anchor
the dialog and other central dramatic sounds. In music, however, it can
reduce the apparent width of the front stereo spread, and the apparent
spaciousness of the music is correspondingly lower. Also, the subwoofer
is not absolutely necessary, although it sure is fun, and you cant
get the bass oomph without it. With music, you can get by with just four speakers
and the results, while not any more or less hi-fidelity than 5.1 can be
much more fun than stereo, particularly in a dry acoustic room environment.
Stereo recordings played through an amplifier that generates additional
signals for the rear speakers can, depending on the processing chosen,
yield immersion surround or a sense of reverberation through the back
channels, as if you were in a concert hall (of adjustable size). Again,
accuracy doesnt enter into the discussion, but this extra processing
can sound very exciting.
Surround sound has finally seen off the old purist classical music arguments
that a recording should recreate the original sound. Even at the time
of quadraphony, earnest articles would be written about how certain microphone
arrangements captured the sound field in the performance
hall. Fine, but that ignored the existence of the listening room. With
surround, the listening room comes to the fore, and we can only optimize
our surroundings for the sound we enjoy the most. Any further arguments
about speaker placement might be as rewarding as those about whether
broccoli or beetroot tastes better.
In 2001, DVD-Audio playback units were appearing
slowly. However, the disks cost
more to remix for surround, and this is still reflected in disk prices currently
higher even than those for a typical DVD video disk.
Of course, there had to be a problem.
Sony developed their own SACD audio system, which is incompatible
with DVD-Audio, and issued some expensive disks which they
first insisted were for 'semiprofessional users', whatever that might have meant.
After another version of the beta/VHS video cassette format wars of the mid seventies, and similar waste of company resources and your money, SACD is the only man left standing. These disks work on any DVD player, as does any CD. And that's all, folks. We've arrived at our final destination, for better or for worse.
Sound at the Stereo Society:
Surround Sound, an Introduction
by Mike Thorne.
Where are we now?
and Music (1974)
by Mike Thorne.
Originally published in Hi-Fi News and Record Review Annual, UK, 1974
About the musical
possibilities of quadraphonic surround sound, and some speculation about
potential future developments. The ideas still apply in today's 5.1
surround sound environment.
by Paul Myers (Director, CBS International
Masterwork) and Bob Auger (Bob Auger Associates).
Originally published in Studio Sound, UK, June 1975.
In fall 1974, in one of the most complex sessions London has seen, Gurrelieder was recorded by CBS for stereo and eventual quadraphonic release. The musical,
production and engineering background is covered, from both stereo and quadraphonic
To Four Sides
of the Moon
by Alan Parsons.
Originally published in Studio Sound, UK, June 1975.
Pink Floyd were among the earliest innovators to use four channel sound, and
Dark Side of the Moon has won many awards, including several for sound
engineering. The author, who engineered these and many other sessions for
the band, discusses the quadraphonic record production, and contrasts it with
the presentation of multichannel sound on stage.
To the Production
of Quadrafile (2001)
by Mike Thorne.
Four sides and four quadraphonic systems, this double album released in 1975
had identical musical sides which differed only in their quadraphonic surround
system. The music varied from Pink Floyd's Money to a special remix
of parts of Tubular Bells. It sounded really good, but then quad
went and died on us.
In suggested reading order (links are provided between pages)
Audio Notes: Mono and Stereo
Surround Sound: An Introduction