Rebecca Chan will play the newly acquired 1714 Guarneri violin, made available to the orchestra through the ACO Instrument Fund. It will join two other Guarneri instruments: the 1743 violin played by artistic director Richard Tognetti and the 1729 cello played by Timo-Veikko Valve and take its place among other fine Italian instruments, including the Stradivarius violin played by Satu Vanska.

Chan describes her instrument as having “a dark, rich tone, like an alto voice, yet capable of great sweetness.” Although the violin is powerful, “it can also spin the most delicate and intimate pianissimos.”

In another debut, American soprano, Kiera Duffy, will perform in Australia for the first time, singing the finale of Mahler’s Symphony No 4 which, in yet another first, Tognetti has chosen to partner Symphony No 6 by Sibelius.

Neither of these works has been performed by the ACO before but Tognetti sees nothing unusual about stretching its repertoire to include significant works, just as it did in performing Beethoven’s Ninth Symphony and Brahms’ Symphonies One and Four.

“There’s no such thing as chamber orchestra repertoire,” Tognetti says. “We play whatever we can. Although both these symphonies are colossal works, Mahler liked to think of his work as more of a chamber music piece and he actually wrote it with a string quartet in mind. There’s a lightness in it. And the Sibelius is a terrific piece to put against the Mahler. I hope that the balance works well.”

Tognetti describes how the two composers met when Mahler was on tour and the two took pleasure in walking in the forest together.

“There’s the wonderful thing about Sibelius who said that he always thought about the place where he was born and the falling snow when he thought about his Sixth Symphony.

“Mahler, on the other hand, summed up his notion of the symphony as being the whole world and you can hear this. People talk about structural form but it’s a kaleidoscopic sound. Anyway, it’s interesting to look at them together.”

The moods in Mahler’s symphony move from innocence and a childlike simplicity with sleigh bells and folk rhythms in the opening of the first movement to a sense of hysteria, panic and a premonition of death as the finale’s main theme. In the scherzo two violins are required, one tuned a tone higher than the other, to create Death’s eerie dance.

Tognetti will not only conduct but use both violins - a challenge indeed. “Well that’s something that I’ll be facing in the next few days,” he says. “It’s part of my job - but just look at me as a conductor.”

Duffy will sing the setting of Des Knaben Wunderhorn, from an anthology of German folk song and poetry, in the final movement. “She has one of those light, very flexible voices which is absolutely right for this,” Tognetti says.

“A young girl imagines what heaven might be like,” Duffy says, “and, not surprisingly as it is told from the perspective of a child ... the images are quite simple: there’s an abundance of food, St Martha is cooking up a storm, there’s lots of dancing and skipping and laughter, even by St Ursula, and St Cecilia and her friends play the most beautiful music that one’s ever heard.”

But there’s menace within this playfulness with the mention of Herod waiting to capture a frolicking lamb and lead it to death and St Luke slaughtering oxen ‘without care or consideration.’

“There’s a plethora of interpretations of the text,” Duffy says, “and I think it’s best if I don’t divulge my own personal feelings about it. I just hope to honour Mahler’s interpretation of the text. The most important thing that I can do is to be an open, honest vessel for this story.”

The breadth of Duffy’s repertoire is breathtaking, ranging from baroque to contemporary and from oratorio to opera.

“I don’t think I could ever be happy being (simply labelled) ‘a Verdi singer’,” she says, but she adds that there are pieces by Mahler that she finds deeply moving no matter how many times she listens to them.

“I’m not really an ingenue at heart,” she says, “but, oh, how I would love to sing Kundry (from Parsifal) or the Marschallin or Elektra,” - certainly not your innocent girlie roles.

“If I had to choose a role that might be within the realms of possibility, I would go with Berg’s Lulu, hands down (but) I wouldn’t dare touch that role until I’m 40.”

ACO presents Mahler 4 & Sibelius 6. Australian Chamber Orchestra. Canberra: Llewellyn Hall, ANU School of Music. Saturday, June 21, 8pm Bookings: ticketek.com.au or 1300 795 012