For the cello, an amplified role in the avant-garde

As one of the few cellists to have made a career as a jazz soloist, Erik Friedlander believes his instrument is comfortable in the worlds of jazz, popular, and avant-garde music. "Musicians are opening up to what the cello can do," he says. "If you play saxophone you have the weight of history on your back. We don't have that to live up to so we can create our own way."

Mr. Friedlander's fellow downtown musicians might agree. The cello is becoming the preferred instrument among many experimental rock bands, forward-thinking composers, and promoters of avant-garde concert series.

This past June, at the Bang on a Can Marathon, an annual festival of new music in New York, cellists were the backbone of several of the headlining groups including Real Quiet, a chamber trio consisting of cello, piano, and percussion; Odd Appetite, a cello and percussion duo inspired by Balinese gamelan and South Indian music; and the Bang on a Can All-Stars, the organization's house band, which features the amplified cello of Wendy Sutter.

Elsewhere, cello soloists are tweaking the instrument's serious image. The Canadian cellist Jorane has released five albums in which she simultaneously sings and plays the cello in songs by artists such as Donna Summer and Daniel Lanois. On Friedlander's new album, "Block Ice & Propane," he evokes American roots music by using lots of banjo-style plucking along with traditional bowing.

The cello's popularity outside of the classics is partly driven by necessity: The lean standard repertoire for the instrument consists of four or five major Romantic concertos.

"There isn't this huge weight of repertoire," says Dorothy Lawson, a cellist in Ethel, an amplified string quartet. "A pianist can't even hope to learn the complete piano repertoire in a lifetime. A violinist can barely manage the major violin repertoire. But as a cellist, you can definitely play the whole cello canon. You very quickly start looking beyond that." [Editor's note: The original version misidentified Ms. Lawson.]

Friedlander points out that rock musicians are becoming more aware of the cello's range and see it as an alternative to the violin, with its folk fiddling or jazz associations. "Because it's not saddled with bluegrass, 'le jazz hot,' or any of those things the violin has, you can put the cello into an indie-rock situation and it doesn't have baggage," says Friedlander, who has performed with indie-rockers such as the Mountain Goats and John Vanderslice.

A major inspiration for many cellists seeking to expand their repertoire is Mstislav Rostropovich, who, before his death at age 80 in April, helped bring about some 100 cello pieces including concertos by Shostakovich and Prokofiev. "He was such an inspiration not just as a cellist or musician but as a creative force," says Ha-Yang Kim, a cellist and composer who performs in Odd Appetite.

Indeed, there is evidence that the cello repertoire is growing at a faster rate than a decade ago. Music publisher Boosey & Hawkes reports that it published 52 new pieces for the cello in the past eight years, up from 41 works in the previous eight years.

Many recent cello works incorporate pop-style ingredients. In May, cellist Matt Haimovitz joined the Berkeley Symphony Orchestra to première Tod Machover's "Vinylcello," which pairs the cello with live electronics controlled by DJ Olive. Cellist Maya Beiser frequently gives recitals with a video component.

Cellists concede that there are drawbacks to the instrument – it is difficult to learn, expensive to own, and with its dark amber tone, it struggles to cut through rock textures. Yet it also seems to benefit from a certain sex appeal. Recently the British classical music magazine Muso surveyed its readers and found that, of all of the instruments in the orchestra, the cello is the "sexiest instrument."

"A certain kind of personality is attracted to the cello," says Ms. Kim, who cuts a sleek, black-clad figure on stage. "Cellists tend to be laid-back and cool. Besides, it's a really gorgeous instrument." [Editor's note: The original version misidentified Ms. Kim.]