The California Symphony has its final concert of the season this weekend, and will be expanding the sounds coming from the orchestra in several ways. For Bruckner’s Seventh Symphony, there will be four ‘Wagner tubas’ in the brass section, and in the violin concerto by Katherine Balch having its world premiere, there are some effects that the string players had never encountered. Donato Cabrera leads the concert at the Lesher Center in Walnut Creek Sunday afternoon.

There’s more information about the concert at the California Symphony website.

One of the many challenges of being a composer who wants to stretch the sonic palette, is that there can be a big difference between the sound you’re hearing in your head and the notes the orchestra produces. “There are ways, effective ways to communicate any material for orchestra,” Balch says, “and it is a learning process to figure out how to communicate that. And how to take complex ideas and distill them to their most fundamental pieces that resonate and sound good with the orchestral body. And that’s just a lifelong learning process that the California Symphony has sort of jump-started for me.” One advantage that she has in this situation, is because she’s their composer in residence, back in January, as she was writing the piece Artifacts — which will be premiered by the orchestra and violinist Robyn Bollinger — she was able to have a rehearsal to determine if the sounds would match. In one of the movements, she wanted an autumnal sound, which made one think of leaves in the woods. “I had this idea of this sense of rustling that you don’t quite know where it’s coming from, so I have the inside strings gently rustling little pieces of plastic. Used plastic bags, to sort of see if that effect even works, or sounds cool, or if it’s gimmicky. You know, maybe it’ll be totally silly, but maybe it’ll sound really beautiful.” Some of the violinists were also given small sewing thimbles for particular passages. “if you mute the strings of a violin or any string instrument with your left hand, and then tap very gently in the upper register, like between the neck and the bridge with the thimble, it’s a very high delicate clicking sound, and I thought that also sort of evoked this gentle, autumnal chirping, or bugs rustling, so I’m again having the inside chairs do that.” In just a short rehearsal, she was able to hear what it might sound like, and whether it would work in the context of the piece.