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BRINGING SOUND TO THE THEATRE AUDIENCE

A ramble through some historical developments

By Peter Wolfenden
Sound is movement. Repose is dumb. focuses radio waves, just as the sailing
(1/p95)
All sound, all noise, tells of motion; ship focused sound pressure waves.
it is the invisible telegraph which All manner of objects were used to
(1/p1)
Nature uses. maximise sound levels in the early
Theatre and cinema rely on sound. years of large theatre construction. In
Some might deny this, citing the one case a number of triangular,
examples of mime and the silent screen, vertical columns at the sides of the
but on reflection, both are augmented stage, could be rotated on their axes.
by sound effects and musical These were adjusted to reflect sound to
Theatre of Vitruvius
accompaniment. Even the earliest the audience. The hard surface was
shadow plays relied on sound to preferable to folding screens or
niches or cavities in the walls acting to
reinforce the story's message. curtains, which absorbed sound at its
focus sound, rather than resonance
When showmen and their theatrical within the bells. (1/p102) source.
troupes moved into large, enclosed The move from the amphitheatre to
venues, the problem of sound roofed buildings brought new problems.
distribution became acute. The broad All manner of theatre fittings can work
and the bawdy were easily against the effective propagation of
communicated, but if an audience could sound. Platforms, pillars, boxes and
not follow what the actors were saying, seats - each has distinctive properties of
or hear what they were singing, then all reflection, absorption and resonance.
sense of plot was lost. Many old theatres present twin
Gradually, the idea of a ‘sound headaches - how to introduce acoustic Stage sound reflectors
friendly’ building took hold, using treatments without desecrating a much-
devices that focused or reflected sound loved interior. A lack of attention to acoustics
from the point of origin to the audience could be costly. Excessive sound
Large domes often produce
at large. reflection often rendered a fine
excessive resonance. An example is St.
Acoustics was a complex beast to Paul’s London, but the dome of St. auditorium almost useless. The
master. Clear sound to one person may Mary’s Dresden is remarkable for the designers of the early opera houses
be muffled sound to someone sitting in absence of resonance. believed that the most advantageous
a different part of the building. One Some halls were configured with auditorium shape was the quarter of a
surface or shape may cause an echo, the speaker’s desk located at the focus circle, because the walls would help to
another deflect sound or enhance of a parabolic surface, which was often direct the sound to the audience.
resonance (prolong the sound). the wall at one end of the hall. The
The ‘tuning’ of a concert hall parabola, if constructed correctly, will
requires much empirical measurement collect diverging sound waves (from the
and experimentation to make the space speaker) and reflect them in a parallel
really ‘work’. At the Sydney Opera nature into the body of the hall. This
House and Melbourne Concert Hall design was used in some ancient
(now Hamer Hall) reflective devices basilicas. (1/p109)
are often floated above the performance
area to help direct sound waves into the
An advantageous form
auditorium. Alas, in some venues, over-
powered amplification systems become Two other rules were adopted:
the solution to poor acoustics. Parabolic and conical walls raised seating should follow a direct
line from the stage to the roof at the
TRIAL AND ERROR
Billowing sails on a ship can rear of the auditorium and the rear wall
The ancient Greeks tried to augment
effectively focus sound. In one case, the should be a concave curve to enhance
sound in their amphitheatres. Inverted (1/p110)
bells of San Salvador were heard on a sound for those sitting at the back.
brass bells were placed over conical
vessel some 160km off the coast of Many architects were constrained
supports located in niches of the walls
Brazil - provided the observer was by the client from applying their
of the Theatre of Vitruvius to increase
standing in the correct position before knowledge of acoustics. Frequently
resonance. In other theatres vases of
the mainsail. basic laws were ignored in favour of
baked clay were sometimes substituted
Satellite receiving aerials on city visual embellishments!
for cheapness! Their effectiveness is a
buildings are a modern variation on
matter of debate. Any acoustical re-
focusing sound. In this case the dish
enforcement was more likely due to the
24 2007 CINEMARECORD