The curator and host of the monthly event - which now regularly attracts up to 80 people, who bring their vinyl records in for others to listen to on the NFSA's high-quality sound system - says, "We didn't expect it to get this big."

A wide range of music gets played, Kaeding says, everything from progressive rock like Genesis to comedy songs by Tom Lehrer to Richard Wagner's Ride of the Valkyries to Bulgarian folk music.

"One person brought in a record they'd just [made] - experimental electronic rock. It was quite good, actually. It went down really well."

The rarest record ever played was the 1973 Vic Simms album The Loner. The first Australian Indigenous protest album, it had very few copies released on vinyl. A Vinyl Lounge regular, Tim Kilby, had bought it in Orange in 1974 and brought it in earlier this year to acknowledge NAIDOC week. He donated it to the NFSA.

So popular is the event that Kaedling says he doesn't often get to play music much himself nowadays. His own favourite track on vinyl is the 10-minute instrumental Hallogallo by the Krautrock group Neu.

"It was brought out in 1972 - there's a driving drumbeat all the way through and a hypnotic beautiful guitar ... People tend to stick around for it."

Kaedling says on October 19 there will be a new addition to the series with the first Cassette Lounge.

"People can bring in their old mixtapes - but they have to tell us the stories behind them."

The fourth birthday of Vinyl Lounge is on Friday October 6 at 5.30pm (drinks available from 5pm) at the National Film and Sound Archive. The first Cassette Lounge is on October 19 at 5.30pm.