Bell worth listening to

Barbara Hall — 10 November 2000
http://www.rmit.edu.au

A composer and a sculptor from Melbourne have developed the world's first harmonic bells. By the end of 2001, there will be 2069 of them.

Casting the first harmonic Federation bell in Castlemaine, central Victoria. Photo by Barbara Hall.     3D computer graphics show the adjustments to the basic bell shape. Image provided by Neil McLachlan . Ross Edwards (left) and Neil McLachlan at the Castlemaine launch of the project. Photo by Barbara Hall. Examining the prototypes

When composer Dr Neil McLachlan decided it had to be possible to cast a true harmonic bell, the three years' research that engrossed him and sculptor Anton Hassell produced many significant outcomes that involved other intellectual explorers along the way and will soon give delight to a lot of people.

In May 2001, the most public result of their research will become the Field of Bells, a permanent public art work installed in Melbourne, timed to celebrate Australia's Federation centenary.

In the Melbourne Town Hall, the federation festival will feature a new Australian symphony using eleven of the twenty-five McLachlan and Hassell harmonic bells which are being given by the Victorian Government to the Melbourne Symphony Orchestra.

A third outcome will be 2001 tuned handbells housed in the new Melbourne Museum, and available on loan to communities around Victoria.

A lasting, world-wide legacy is that, for the first time, bells truly can be counted as musical instruments with timbral characteristics that composers can include in all orchestral scoring.

Neil McLachlan, who has a PhD in physical chemistry, is a research associate and adjunct professor in RMIT University's School of Architecture and Design where he is developing new courses and an acoustics design studio.

Anton Hassell, co-director with Neil of the Australian Bell Company, is casting many of the smaller bells at his art foundry at Mia Mia. He is completing his PhD in public art for architecture and design at RMIT University, where he shares a research office with Neil in the Faculty of the Constructed Environment.

The dream three years ago to create the world's first harmonic or tuned bells flew in the face of widespread scientific negativity. McLachlan and Hassell were prepared for the long haul, and the fact that, as Neil said, "many great discoveries are at the edges of known disciplines." So they were not surprised that the project required them to forge collaborations with musicians, acoustic engineers, computer engineers, aerospace engineers, universities-principally the nurture of research within the Faculty of the Constructed Environment-and a foundry at Castlemaine run by the Billman family. There were also hundreds of hours of refined computer modelling, and struggles with finance because of the great divide in the funding of science and art research.

In August 2000 Ross Edwards, the Sydney composer whose third symphony will use 11 of the new two-octave bells with the Melbourne Symphony Orchestra next year, watched the dramatic pour of 1800 degree Celsius molten bronze to make a 2 tonne bell for the Field of Bells. He said he would be pleased to see the end of tubular bells in the orchestral line-up.

"I hope they go. Most composers can't bear them. The new bells bring in a whole new set of sounds to composing," he said.

Neil McLachlan said "it will create many new opportunities in music performance and composing. A bell that can match the harmonic sequence of the human voice has true pitch, a very pleasing sound."

Until these determined Australians, western bells have not really been instruments in the orchestral sense. Carillon bells, not used in a musical setting, don't require tuning.

"The engineering design process will apply to all percussion instruments, xylophones and gongs and bells. With funding now at this point we could make bells with any ratio of frequency. We have also designed various polytonic bells, individual bells with two or three pitches," Neil said.

It has taken almost three years. At the August launch and pouring, Neil and Anton proudly introduced the harmonic overtones and soft melodic tones of some of their bells to an audience which included the State Minister for the Arts and Minister Responsible for the Centenary of Federation, Hon. Mary Delahunty.

Stringed instruments, which vibrate in one dimension, have a harmonic sound. Three dimensional vibrations could not be tuned harmonically until now.

"The sound of a bell is a series of frequencies called partials. When these partials fall into a certain series, they are called a harmonic sequence. Harmonic sequences are the basis for the human voice and most musical instruments. They're what we use to determine pitch. This will open up a whole lot of new possibilities for bells to be truly integrated into new compositions: for the first time, they can be actually scored for," said Neil McLachlan.

In the seventeenth century, bell makers started tuning their handiwork in the hope of achieving a harmonic bell. By the end of the nineteenth century, they had worked their way up to five partials but, Dr McLachlan says, "one extra partial frequency was added to the harmonic series. It was tuned to a minor third interval and creates the ambiguity of pitch heard in these bells. Most nineteenth-century bells are pretty out of tune."

Very little happened until the 1980s when engineers in a Dutch bell foundry started using computerised finite element analysis, creating three-dimensional models to predict an object's mechanical properties. Using this method, the Dutch tuned the individual partials-moving the minor third to a major third interval-which improved the sound but was not a true harmonic bell.

It seemed impossible to create a true harmonic bell using the classic European bell shape, so McLachlan and Hassell walked away from the European bell shape. They wanted to keep their options as wide open as possible and start trying some radical strategies.

"The only rules were that it be semi-enclosed and made of bronze," McLachlan said. Then they came across some powerful software and hardware. McLachlan found that a soon-to-retire RMIT mechanical engineering colleague, Dr Josef Tomas, had in his company, Advea Engineering, developed software called ReSHAPE to analyse and fine-tune 3D models of car parts to control vibration and reduce noise. McLachlan realised this was just what they needed to study, predict and alter individual partials of bells.

Josef Tomas was delighted. His software had been used by the big names in the industry: Volkswagen, Ford, General Motors.

"It's so much more poetic than air bags and car crashing. Of course, we had to change the program. We'd only ever tried to get rid of noise, never make it," he said.

Using computer music software, McLachlan would create a bell and run it through another program to hear how it would sound. He then asked ReSHAPE to help by computing optimal design solutions by configuring the 3D model to a specific individual partial while leaving other, already tuned, partials unscathed. Computers were used to model not only the ways bells will vibrate but how people hear.

From this point, new manufacturing technologies enable the designs to be produced with high precision. Inside and outside shapes produced with laser cutting technologies are turned in resin-coated sand, and these segments are then assembled to complete the mould.

"We are looking forward to having them in the field where people can walk among them. In bell shaping, the object brings our art forms together. This musical instrument is a also public sculpture," said Anton Hassell.

The prototype is a conical bell with seven harmonically tuned partials. Although there are additional partials in a harmonic sequence, this is a true harmonic bell because these other partials cannot be heard by the human ear.

In traditional bell tuning, foundries cast a bell and bore it out until the makers find a sound they like. The more exacting techniques developed by McLachlan and Hassell involve hundreds of hours of number-crunching on the SX-4 computer for each bell design. The program can control the timbre and indicates the correct three-dimensional form-the only way to model improvements.

Neil McLachlan was writing music for the Melbourne-based Danceworks company in 1989, then formed his own company, Gonghouse, when he began wrestling with how to tune bells.

"We set out to make musical works for gamelan and classical Indian bells and percussion. I also did a lot of work at Lake Tyers, with the Aboriginal community, developing performances using their own stories and instruments," he said.

Righting the acoustic wrongs embedded in the hierarchical history of western music was behind the work Neil did with a Yongu musician from the Northern Territory, finding a way to tune the guitar to the didgeridoo instead of the reverse. The solution involved replacing all the frets. Neil also worked extensively in the Philippines, helping build instruments for indigenous people to dance to, as part of their evidence for land rights claims.

"I don't use western timing, I use just tuning. Music was commodified after the industrial revolution because of the demands of mass production. There was a break with tradition. For the first time, instruments and their tuning had to be standardised, because scores were being written down for the first time," said Neil.

The explorations of non-conformist American composer Harry Partch became a model for Neil. "Consonance is about the need to control the timbre," Partch wrote.

Neil was intrigued but not convinced by an article written in the mid-eighties by Dr Andre Lear, the eminent Dutch musicologist and bell expert, claiming that a pitched bell was an impossibility. Trawling the literature of several disciplines, MacLachlan came across Neville Fletcher at the Australian National University who was working along the same finite element analysis path as the Dutch engineers and had co-written with Thomas Rossing what McLachlan considers the bible of instrumentology, a book called 'The Physics of Musical Instruments'. But they too believed there could be no harmonic bell.

"In 1998 in Japan, China and Korea I photographed temple bells and recorded their sounds. Some date back to the sixth century. I entered their sounds on my PC to measure the frequencies of their partials, or the different notes within each ring; as well as the partials of many bells of Europe. This was the way we started designing bells whose partials would all sound harmonious when played together: Perfect partials equal perfect harmony," said Neil McLachlan.

The computing meant Dr McLachlan could 'ring' a bell without that bell ever having been cast. "It's a lot easier to redesign a bell on a PC screen than it is to change it when it's 25 kg of bronze," he said.

Support worth $2 million for the harmonic bells project has come from Arts Victoria and the Melbourne International Festival for the Arts. There has also been intellectual and in-kind support from Elizabeth Lindqvist, the head of the acoustics laboratory in RMIT University's Faculty of Applied Science. Josef Tomas linked McLachlan with bright research students, notably Behzad K. Nijieh, who was educated in rocketry in Russia and is doing his RMIT aerospace engineering doctorate on a space debris collection mechanism.

Behzad and Neil recently co-authored an article in a mathematical magazine on the vibrational behaviours of cylindrical forms. Neil has posited the concept of a museum of sound in 'Museum' magazine and published work on acoustics in 'Architecture Australia'. His article on notated rhythm in cyclic form was published in the 'Leonardo' music journal.

Neil McLachlan's most recent installation work was a set of gongs for Sydney's new Olympic Park.

For the Field of Bells, in the new Riverside Park being built by the City of Melbourne, the largest of the forty-three free-standing, electronically controlled bells weighs 3 tonnes and stands almost 2 metres high. In many shapes, timbres and tunings, the bells will chime regularly during the day, play specially composed soundtracks and be a feature of performances in the park over many years.