Slava, Rodrigo, Beethoven VII by the Australian Chamber Orchestra

Among string instruments it is the sound of the cello and the guitar that can most often remind us of the moods and emotions expressed by the human voice.

At the ACO's next concert directed by Richard Tognetti, the audience will hear the unique voice of the 1729 Giuseppe Guarneri filius Andreae cello donated to the orchestra by philanthropist Peter Weiss and played by principal cellist Timo-Veikko Valve. As well, the voice of the traditional guitar made by South Australian luthier Jim Redgate will reverberate throughout the hall as Slava Grigoryan plays as soloist in Rodrigo's Concierto de Aranjuez.

Weiss, who has supported the ACO for more than 25 years, finally agreed to have his identity as the donor of the remarkable Guarneri instrument revealed in the hope that others might follow his lead in contributing to Australia's cultural legacy. His gift of this instrument, valued at $1.8 million, is the biggest single gift in the ACO's history.

"This cello is an amazing voice box," Valve says of the Guarneri. "It helps you with all the tiny little things between the notes. It is a unique voice; a very dark instrument with a sweet chocolate, velvety tone." Valve affectionately calls the instrument "Barry", a name suggested by another ACO cellist, Julian Thompson, because of the similarity of its voice to the rich, resonant voice of the late American singer Barry White.

"It's not the instrument for the 'hero soloist' but perfect for the type of player that I am," Valve says. "It can do many tasks. Julian reckons that the Guarneri is a beautiful continuo cello and that links into its suitability for chamber music."

It is chamber music that is Valve's particular passion. "I've been with the ACO for 10 years now but chamber music was my musical life before I joined the ACO and what we do in the orchestra is not too far from that mindset," he says. "But this concert is our biggest formation this year. We don't get to play this symphonic repertoire so often but Richard (Tognetti) is remarkable with Beethoven symphonies. They suit his personality."

There will be 36 musicians on stage to play this program beginning with Ravel's collection of baroque dances, Le tombeau de Couperin, and moving on to Rodrigo's guitar concerto and Beethoven's joyful Symphony No. 7.

Slava Grigoryan first played the Rodrigo concerto with the ACO 20 years ago. He is artistic director of the Adelaide International Guitar Festival, a winner of two ARIA Awards and an international musical performer, often playing with his brother Leonard.

The brothers for some years used Redgate guitars with a double-topped construction, somewhere between a traditional and a modern guitar, but the guitar that Grigoryan will use at this concert is modelled on a traditional Spanish instrument.

"It has a big sound and an amazing and authentic range of colours," he says. "It's voice is very clear, well-balanced and open with warm, slightly woody, tonal sounds." Grigoryan describes the Rodrigo concerto as a very emotional piece, which has both great sadness but also festive moments. "It balances simple with complex emotions and the story-telling is very obvious."

Stories abound about the inspiration for the yearning sadness of the second movement of the concerto. Was it inspired by the bombing of Guernica in 1937 during the Spanish Civil War? But in her autobiography, Rodrigo's wife, Veronica, wrote that it evoked both happy days during her honeymoon and her husband's devastation when she miscarried their first child. They later had a daughter, Cecelia, and the first movement perhaps reflects the happiness of this event. Grigoryan believes that the movements were not composed in the order in which they are now played in the concerto.

Grigoryan's interpretation of the work has been affected by several recordings he listened to as he was growing up. "I took on board a few bits from other players," he says.

This virtuoso guitarist has a diverse repertoire and next week his new CD, Bach's Cello Suites, Vol 1, on ABC Classics will be released. Yes, cello suites, but played on a baritone guitar illustrating the closeness of the voices of these different instruments.