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Ambient Sound and Resonating Spaces

What is ‘ambience’?

Ambient (adj.) Surrounding; of the surroundings
Ambience (n.) the surroundings or atmosphere of a place

• atmosphere • feel • environment • mood • quality • character •

What is ambient music?

So just who was responsible for the idea of ‘Ambient Music’? Well, depending upon your research sources, which books you have read or who’s music you listen to, your answer might be Brian Eno. Whether or not you believe this to be fact or fiction it is still worth reading a couple of Eno quotes:

"Ambient Music must be able to accommodate many levels of listening attention without enforcing one in particular; it must be as ignorable as it is interesting."

"My friend Judy Nylon visited me and brought me a record of eighteenth-century harp music. After she had gone, and with some considerable difficulty, I put on the record (Eno had just been released from the hospital and was bedridden). Having laid down, I realized that the amplifier was set at an extremely low level, and that one channel of the stereo had failed completely. Since I hadn’t the energy to get up and improve matters, the record played on almost inaudibly. This presented what was for me a new way of hearing music–as part of the ambience of the environment just as the colour of the light and the sound of the rain were parts of that ambience. It is for this reason that I suggest listening to my pieces at comparatively low levels, even to the extent that it frequently falls below the threshold of audibility."

There have been others before Eno who were producing their own ambient pieces, most notably Erik Satie and John Cage. It is a well-known fact that the silences in Cage’s 4’33" were not, after all, silences, since silence is a state which is physically impossible to achieve. At Harvard University in 1951, Cage visited the anechoic chamber, the surfaces of which were insulated with absorbent material and designed to be echo-free–an environment that might be as near silent as technologically possible. Cage maintained that he still heard two distinct sounds coming from within the space: one high, which he claimed to be the sound of his own nervous system and the other low, the sound of his blood circulating. As a result of these experiences, Cage proposed that the term silence should now be described as ‘non-intentional sounds,’ or, from a compositional viewpoint, sounds not intended or prescribed by a composer.

Clearly Cage is ‘forcing’ the listener to listen in a very new way. The sound source is now far from obvious. We are listening to the whole, to everything, to the ambience. This ambience has always been there, but whether or not we pay any attention to it is another matter.

Early Ambient Sounds - ‘Built-by-Man’: Stone Henge (England) and Burial Chambers

There has been research produced over the past few years into the possibilities of burial chambers, and most notably Stone Henge, having certain acoustical properties to create distortions in the spatialization of sound, ie. related to standing waves in man-made spaces. While it will probably remain unclear how much knowledge Stone Age man had about the physics of acoustics, it could be assumed that ambient sounds– particularly distortions in ambient sounds–were a part of the life of early civilizations and may have had a role in their religious ceremonies.

Science of Acoustics: Vitruvian Resonating Vessels

The Roman Architect Vitruvius’ understanding of acoustics is extremely impressive for its time. Vitruvius belonged to the Stoic school of philosophy whose followers were aware of the wave analogy for demonstrating acoustical science (for further information on the Stoic philosophy see G.E.R. Lloyd, Greek Science after Aristotle, Chatto and Windus, 1973).

Imagine a stone being thrown into a still pool of water. The impact causes concentric waves to spread across the surface. This analogy demonstrates how sound spreads in all directions. It also demonstrates what happens to a sound when it reaches, or touches, a reflective surface–the sound waves are deflected. Vitruvius’ understanding of this reflection was that it created interference to the original source and in relation to sound, the original source becomes less clearly audible or defined.

Vitruvius called this reflection of sounds resonantia (which differs somewhat from our modern day meaning of the word resonance which implies a sound being bounced back and forth repeatedly at a specific pitch).

Photo courtesy of Rob Godman : Audio Installation by Rob Godman at Prema Arts Centre, Gloucestershire, U.K.

The resonantia would have been seen as a considerable problem in Roman and Greek theatres. If strong reflections come back to a listener at slightly different times, then speech, for example, would have become difficult to understand. As Vitruvius pointed out, an inflected language such as Latin is difficult to understand when the final syllables of words arrive at slightly different times.

Roman and Greek theatres (which are semicircular as opposed to amphitheatres which are circular) have relatively good acoustics for speech. Anyone who has tried listening to speech in such a theatre is likely to be impressed by the clarity of sound no matter where one sits (there is no real ‘sweet-spot’). These theatres were outdoor venues often built into the side of a hill. The apparent dryness of the resultant acoustic was a problem for Vitruvius when dealing with music and he went to considerable efforts to invent a system that would counteract it. Resonating bronze vessels were his solution to this problem.

"...let bronze vessels be made, proportionate to the size of the theatre, and let them be so fashioned that, when touched, they may produce with one another the notes of the fourth, the fifth, and so on up to the double octave."

"...the voice, uttered from the stage as from a centre, and spreading and striking against the cavities of the different vessels, as it comes in contact with them, will be increased in clearness of sound, and will wake an harmonious note in unison with itself." – Vitruvius, The Ten Books on Architecture, translated by Morris Hicky Morgon.

Vitruvius demonstrated how the vessels should be spatially arranged around a theatre, how many vessels should be used and what their exact tunings should be. He followed Aristoxenos’ tunings and showed considerable knowledge of music theory. It is likely that such tunings would have been used in order to assist instrumentalists and particularly singers with their own tuning. The vessels might be considered an early artificial reverberation unit, with specific frequencies enhanced and others excluded. Obviously ‘real’ reverberation does not function in such a way.

How well might these vessels have worked? It remains unclear, as no examples have ever been found. As has been stated, the musical theory is quite solid for its time. Personally, I find the concept of greater interest than the practicalities.

How has the Vitruvian concept influenced my work?

In 1996-97, I became interested in the concept of creating an acoustical space that could evolve–one that was not static and dependent upon physical constraints. The first ‘showing’ of this type of sound installation took place at The Royal Festival Hall (London) in February of 1998 and was in collaboration with Jason Cornish. The sound consisted of quadraphonic pre-recorded CDs and live signal processing of environmental sounds picked up by directional microphones around the site. The result was an acoustic environment that felt as though it changed without any corresponding change in the physical visual environment.

Around that time, I was invited to compose a sound track for a CD-Rom for Illuminations Interactive (The British Museum, Channel 4 Learning). The project was based upon journeys through Roman Britain and the Roman Empire. The sound track used similar ideas to the installation I created with Cornish in that it made use of exaggerated spatial effects to create changes of feel and atmosphere.

My research for this CD-Rom and also long term continuing work with Jason Cornish led me to discover the Roman architect Vitruvius, and his use of resonating vessels in Roman Theatres. So, in the 1990s, I was creating acoustic spaces with signal processors, tapes and microphones. To my astonishment, it would appear that two thousand years earlier Vitruvius was doing a very similar thing with spatially arranged bronze vessels in Roman theatres!

My interest in the Vitruvian concept was born partly from the combination of science and the arts that was prevalent in Greek and Roman times but also from a psychoacoustic stance. Clearly, the Vitruvian vessels were dependant on external sound stimuli to be heard. Vitruvius stated that the vessels were to be ‘touched,’ presumably meaning that sound waves from a sound source (a musical instrument for example) would radiate outwards and ‘hit’ the vessels making them ring sympathetically.

As a model for reverberation, there are obvious problems–the concept behind reverberation and resonance being quite different. However, it is also true that a reverberation cannot be heard without a sound source being present. As much of my work has involved attempts at abstracting acoustic spaces from their sound source it became clear to me that with the aid of digital technology, it would be possible to abstract the ringing vessels from any sound source by simply triggering its sound mathematically. It would be possible to hear a Vitruvian resonance without the influence of any other sound.

Inside the Eye of Silence

Vivienne Spiteri and I intend to produce an installation work with solo Harpsichord that takes the Vitruvian concept as a model for creating resonant spaces within a multi-room environment.

Imagine moving through a multi-room environment. Each room would have its own fundamental resonating frequency as if each had its own Vitruvian resonator. The harpsichord’s overall resonance–as well as selected and isolated overtones from its rich spectra–will be guided and composed into a work of music through the various and particular acoustic spaces of the entire edifice.

The installation, Inside the Eye of Silence, will be presented as both a live solo harpsichord performance and as a digital audio work using material captured during the live performance. In effect, the rooms will continue to resonate with the harpsichord’s material long after the solo performances have been completed–almost like a continuous echo from the past that grows and evolves out of and returns to the silence which is the essence of the time-life of the harpsichord spectra.

It is likely that the harpsichords spectrum will be analysed in some way and then act as a trigger for the vessels. However, it is also my wish that the sine waves can be modified so that they can take on the characteristic of the harpsichord’s own sound (by using a sample of the live instrument and using it as a waveshaper).


– Jahn, Robert G., Paul Devereux, and Michael Ibison, "Acoustic Resonances of Assorted Ancient Structures," Journal of Acoustic Soc. Am. 99(2): pg 649-658; February 1996.

– Landels, John G. Assisted Resonance in Ancient Theatres - Greece and Rome XIV, Routledge, 1967.

– Landels, John G. Music in Ancient Greece and Rome , Routledge, 2000.

– Vitruvius. The Ten Books on Architecture , Dover, 1960 (original written around 27 BC). (2002) (2001)

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