“I try not to use the word ‘noise’ too much, because people get scared,” Carlos Giffoni said. Speaking via phone from Brooklyn, Giffoni explained how he describes the music of his annual festival, the No Fun Fest, to the uninitiated. “I usually say it’s experimental music – an evolution from modern composition, free jazz, and No Wave music from New York in the early ’80s,” he said. “I think that’s the lineage that these bands follow in.”

That definition may seem complicated, but it’s accurate. During the third edition of Giffoni’s festival this weekend, a cadre of international musicians and artists will descend on the Brooklyn venue the Hook (No Fun’s home for the second year in a row) to showcase a wide range of experimentation: droning atmospheres made with laptops and effects, joyful blare with horns and drums, and raging punk with electric guitars.All told, 48 acts will perform on two stages over three nights.

No Fun’s music might be noise compared to the top 40, but attendees will discover a surprising diversity of sound. “Mainstream music usually has three or four formulas that everyone follows,” Giffoni said. “In the noise scene, that doesn’t exist. It’s open to whatever people want to do.”

Lately, the gap between noise and the mainstream has shrunk due to increased exposure for bands like New York’s Black Dice, Rhode Island’s Lightning Bolt, and Michigan’s Wolf Eyes.The latter is a No Fun staple, having closed the inaugural 2004 fest at Williamsburg’s Northsix with a neck-breaking set. On Saturday, Wolf Eyes will be joined by new member Mike Connelly (whose band Hair Police appeared at the first two festivals) to headline the main stage. Aaron Dilloway, who departed Wolf Eyes last year, will play a solo set on Friday, while record labels run by Connelly and fellow Wolf Eye John Olson will supply acts for the Hook’s downstairs stage on Sunday night.

All this multitasking is emblematic of No Fun’s communal scene, in which many of the performers collaborate and correspond. “It’s like a family reunion,” Olson said while chatting with Connelly after a recent Wolf Eyes gig in Washington, D.C. “It’s by far the most fun weekend of the year,” Connelly added, acknowledging the irony in the festival’s name, which Giffoni adopted after a spontaneous suggestion from Sonic Youth’s Thurston Moore.

Moore and his Sonic Youth band mates have been involved in No Fun from the beginning (guitarist Lee Ranaldo will perform on Friday and Moore on Sunday), as have many veteran artists. This year, grizzled sax-guitar trio Borbetomagus will headline on Sunday; Ikue Mori, a laptop pioneer and member of NYC’s short-lived post-punk band DNA, will play in a duo with Zeena Parkins on Friday; and Smegma, a Portland, Ore., group entering its 26th year of existence, will close out Friday night’s lineup.

“They’re a staple,” Olson said of Smegma. “We wouldn’t be here if it weren’t for them.” Giffoni concurred: “They’re like grandfathers for this whole thing.”

Other highlights of this year’s lineup include Oregonian Daniel Menche (Saturday), who uses his body as a sound source, amplifying his pulse or attaching mics to his throat to cathartic effect; Japan’s Solmania (Friday), hack at custom instruments built from random guitar parts; and Denver’s O.P.C. (Saturday), a pair of 16-year-olds who Giffoni called “the youngest possible band in the scene.”

Giffoni, an electronic noise artist himself, will perform (Friday) with Polish sound artist Zbigniew Karkowski,continuing a collaboration that began last June in Paris. “That was the first time I ever played with anyone where I had to hold my mixer down,” Giffoni said. “It was shaking and almost fell off of the table.”

Because No Fun has brought so many musicians together, it has become something of an international noise conference, galvanizing the scene and influencing the music. “It produced a much needed shift of perception in my head,” said Nautical Almanac’s James “Twig” Harper, who will trek from his Baltimore home to perform a solo set Saturday. “The shock waves for what people are producing will only intensify from here on out.”

“The personal contact adds an amazing depth to otherwise exclusively online relationships,” said Michael Bernstein of Brooklyn’s Double Leopards, who’ve played the festival twice. Two of Bernstein’s other bands, White Rock (Saturday) and Shackamaxon (Sunday), are slated this year. “It demands that we bring everything to the table,” Bernstein said.

The No Fun Fest shows no signs of weakening. The first two years sold out, and this year is expected to do the same. Giffoni hopes to extend that success into other avenues, perhaps taking No Fun outside New York. “There are still tons of people I want to see play,” Giffoni said. “As long as I have the time, I’ll do as much as I can.”

Wherever No Fun goes, its music will continue to surprise. As Olson put it: “If you can’t have fun at No Fun, you’re probably dead.”

March 17, 18 & 19 at the Hook (18 Commerce Street, Brooklyn, 718-797-3007).