Saturday, June 8 At 7.30pm

The Street Theatre

Tickets 6247 1223 or thestreet.org.au

In Ensemble Offspring's next Canberra concert at The Street Theatre on Saturday, June 8, it's not only the music that's new but also the handmade instruments that have been purpose-built to perform the pieces.

''We had the idea of building a program based on Harry Partch and his whole new system of tuning,'' Ensemble Offspring co-artistic director, Claire Edwardes, says. ''So we had to get all these instruments built. We needed to find Australian instrument makers who were open-minded about building something different.''

Partch was born in the American south-west in 1901, the son of former missionaries to China. During his childhood he was exposed to music that ranged from Asian to Native American. He developed music that incorporated elements of speech, making use of natural acoustic resonance with expanded melodic and harmonic possibilities. He named his system of tuning pitches to the simplest possible intervals ''just intonation''. He adapted string instruments to play this music and then began to build entirely new instruments that employed a microtonal tuning system.

Edwardes's search for instrument makers came up with several craftsmen.

American-born composer and sound artist, Kraig Grady, who lives in Wollongong, has designed many microtonal instruments: metallophones, marimbas, hammered dulcimers and reed organs. His centaur vibraphone and huge meru bars will be played by Edwardes and Bree van Reyk in the concert. ''The meru bars are like big pieces of pitched metal,'' Edwardes says. ''They go about two octaves lower than a normal vibraphone.''

The tarhu is a string instrument designed by Linsey Pollak. ''It's like a big violin that resonates in the same tuning system,'' Edwardes says. The undachin tarhu, made by Peter Biffin for Ensemble Offspring, is a spike fiddle that is used by Anna McMichael and Damien Ricketson in the concert.

Pollak's clarinis are wooden tubes with reeds in the clarinet mouthpiece but no keys. They are played by Diana Springford and Jason Noble.

Conventional violins, a harmonium and standard percussion instruments are also part of the group's instrument family.

The concert program features three classics of new music: Fratres by Arvo Part, Music in Similar Motion by Philip Glass and Hidden Sidetracks by Terumi Narushima. ''We'll be putting our own twist on these using this new tuning system,'' Edwardes says.

Then there will be four new works especially written for Ensemble Offspring: Hydra by Amanda Cole, Some Shade of Blue by Damien Ricketson, Akashic Torus by Kraig Grady and also Mysteries by Arana Li.

''We're used to the tone/tone/semitone mode of Western music and sometimes when people hear our different music it seems to affect them in quite a strange way,'' Edwardes says.

''After our last concert at Sydney Opera House, people seemed to be on a real high.''