An audience ranging from old rockers to a baby wearing a huge pair of sound-cancelling earmuffs is gathered in a warehouse performance space in Brunswick East. The guests are subscribers of beloved independent radio station 3RRR, and they’re here for a live-to-air episode of Respect the Rock with Nicole Tadpole to celebrate the show’s 20th birthday. The performance is informal and intimate, with a few rows of picnic chairs set up near the stage, and not a smoke machine or laser in sight.

Roughly once a fortnight, the station invites an audience of subscribers into the 150-person venue for live performances, but the intimate setting belies the fact that since 2008 some of Australia’s, and the world’s, most respected musicians have graced the stage. Folk-rock singer-songwriter Sharon Van Etten, indie-rock band the Kills and alternative rock band Wilco, not to mention a huge list of Australian artists such as Courtney Barnett and Sampa the Great, have all played here.

"Wilco was incredible,” says 3RRR project manager Phillipa Overgaard. “They didn't have a full drum kit with them, so the drummer was walking around the building going, 'Do you mind if I borrow your bin?'"

The sound-engineered performance space is part of the 3RRR office, an independent radio station with more than 40 years of history in Melbourne’s music scene. It’s a well-loved community broadcaster, with 14,000 subscribers and an estimated 800,000 weekly listeners.

Despite the venue’s star-studded history, Overgaard still remembers the first performance as one of her favourites. A team of builders and trade volunteers had just finished installing a roof on the building, and the space was just a big, empty room. To christen the venue, a builders’ band and a Triple R all-star band of announcers set up on the floor and belted out a set.

3RRR started broadcasting in 1976 as a student radio station for the Royal Melbourne Institute of Technology (now RMIT), and in 2004 it moved from Victoria Street in Fitzroy (where it had been since 1979) to a 1940s lingerie factory. The building itself is nondescript from the outside, constructed out of beige bricks supporting a flat tin roof with industrial fans.

Looking at it from the street, you’d be surprised to learn that the 900-square-metre building contains a large office space, four recording rooms, three sound booths, a CD library, a kitchen, a band room, a meeting room dominated by a wall of vinyl and a 150-person performance space – all built mostly with funds from subscriptions.

“If we didn’t have our subscribers, we’d simply cease to exist,” says Overgaard. “When we moved, any money that we had – and we had very little – we spent on the performance space, just getting the basic structural work done.”

While it was constructed with a limited budget, the venue has an incredible sound. A series of sound panels wrapped in acoustic-treated fabric hangs from the ceiling at various angles. You’d be hard pressed to find a right angle in the 3RRR performance space or any of its studios – the rooms are irregularly shaped to prevent sound from bouncing. The space behind the stage is covered in acoustic curtains, which can be pulled back, allowing sections of wall to add different acoustic dynamics.

"Being able to build an acoustic venue purely for that purpose … is quite unique. There's a luxury to being able to do that. It was a labour of love, that's for sure," says Overgaard.

The venue is a recreation of the Rooftop Café – an independently owned Fitzroy cafe that occupied the roof of the old 3RRR station and hosted luminaries such as Jeff Buckley in 1995 and PJ Harvey in 2001.

Aside from major construction like the roof, volunteers and subscribers did most of the work. As a result, progress has been gradual and the venue has evolved slowly over the years and the walls of the band room are covered in drawings and autographs. On one chunk of wall, rapper Sampa the Great has drawn an almost life-sized woman in coloured textas that’s only slightly interrupted where one leg intersects an older tag that simply reads “ask me for amyl” (artist unknown).

As a not-for-profit, self-funded organisation, 3RRR operates largely on the goodwill of subscribers. Live-to-air performances in the performance space are one of the ways the station gives back to volunteers and subscribers. Every single ticket is given away on air, so the only way to get one is to subscribe and listen.

This year’s 3RRR Radiothon on-air campaign runs until Sunday August 25, but you can still subscribe and pay up to enter the prize draw until Wednesday September 25. Prizes include a getaway for two at Brae in Birregurra, passes and flights to Bigsound in Brisbane, and a 12-month Cinema Nova pass.

To subscribe visit rrr.org or phone (03) 9388 1027.