Theatre Design & Technology - Fall 1996 - 46

M-S AND SURROUND SOUND
.lust going from a more or less monaural plal"back to a multichannel frontal pial back does not take full adramage of the
theatre space. .-ulOther important componem of the fulll" deI"eloped Requiem sound Il"as the surround sound system. It is
extremely important in crcating this l\1Je of surround sound
to ensure that the audicncc docs not localizc on anI" loud-

LOUDSPEAKER PLOT FOR
LES LIAISONS DANGEREUSES

S-

n
S+

REQUIEM
MID SIDES
(STAGE)

HARPSICORD
MID SIDES

D
S-

S+

SYNTHESIZED
SURROUND

(AUDIENCE)

THESE LOUDSPEAKERS
AIMED AT THE CEILING

D'
LOUDSPEAKER KEY

MIDDLE

lJ.

SIDE+

S+

n
\

SYNTHESIZED RIGHT
SURROUND

R
SIDE-

S-

SYNTHESIZED LEFT
SURROUND

10&1

SUB WOOFER

spcakers in the audience. Three tcchniques can be emplol"ed
to accomplish this. The first is to use as many loudspeakers
as possiblc. For an artificial rel"erberation sl"stem. one ll"Ould
idcally hal"e a loudspeaker located on el"ery surface from
Il"hich a reflection could possibll" cmanatc. This is not possible on t\Vical thcatrc sound budgcts. although the technique has becn used for ycars bl consuhants such as
Christopher Jaffe Il"ith much success. Our setup used a I"ery
modest ninc surround speakcrs. _-\ second Il"ay to
ensurc that thc audience does not localize on a
single loudspcakcr is to proyide as diffuse a
sound source as possible. This can be accomplished bl" locating thc loudspeakers as far all"al"
(espccialll". bel"ond thc critical distance) as possible. and to aim the loudspeakers at diffusing
surfaces. \ote that three of the surround speakers in the audience space Il"ere aimed at the ceiling. Finally. a third method used to minimize the
localization is to electronicalll" delal" the surround feed such that the sound from the surround system an'il"es at thc audience after the
sound from thc ~I-S loudspcakers. Since the
harpsichord and Requiem scorings Il"ere ahral"s
plal"ed separatell". t\l"O differem delal" senings
could be employed.
There MIS some flexibilil\- in creating the
feed to the surround sl"stem due to the fact that
the cues Il"ere electronically manufaclllred
rather than recordcdlil"e. Since the S componems in scoring were deril"ed from ~l originals.
the surround feed used primarily ~l componems. Il"ith S componems being adding onll" for
particular cues. The surround signal. after delay,
MIS further cnriched Il"ith elcctronic rel"erberation. Il"ith the reverberation output adjusted to its
R f'-,
full "ll"et"' position. (i.e. no input signal mixed
[..-J
Il"ith the processed signal). For more diffusion,
the synthesized left and right "stereo" outputs of
the effects unit Il"ere distribllled to alternate surroundloudspcakcrs.

M-S TECHNIQUES IN
PERFORMANCE
From thc momem II"C fircdup the emire sl"stcm.
I Il"as amazed! \ot onll" Il"as the sl"stem capable

of localiZing to thc center of the action. but the
idemity of indil"idual loudspeakers secmed to
disappear. It II-as thc first cxpcriencc I'l"e had in
ml" 011"11 sound score dcsign II"0rk in lI'hich I Il"as
happl" with the spatial characteristics of thc
sound. The underscoring Il"ith the Requiem
sccmcd not only to come from Il"ithin thc visual
spacc of thc actors. hut it also seemcd to he as
lI'ide as the acting space-and from virtuallv every seat in thc audicncc.
Thc nct rcsult of thcsc tcchniques Il"as to

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