NEW YORK (AFP) - Hitting the road with his band in a beat-up van, Sean Bohrman looked at the cassette deck and, instead of seeing an ancient relic, became inspired. He could listen to his own, and others', albums on the cheap.

Seven years later, Bohrman helps run a label out of southern California, Burger Records, which has sold 350,000 cassettes - tiny in the universe of the music industry, but marking an unlikely mini-revival of an often-derided format whose obituary had been written in the 1990s.

"No one, least of all us, expected this to happen," said Bohrman.

In an age where vast volumes of music can be downloaded instantly for free, vinyl has witnessed a rebirth among collectors, with LP sales soaring by one-third in the United States in 2013 alone.

In an effort reminiscent of events to promote vinyl, dozens of record stores around the world on Saturday held a special cassette day to sell tapes ranging from the new album by rising indie band Foxygen to reissued classics by ironic rockers They Might Be Giants.

Few expect that cassettes - notorious for getting jammed and unspooled - will again become the dominant format as in the 1980s before compact discs took over. Last year, cassettes accounted for fewer than 0.1 per cent of the 289 million albums sold in the United States.

CDs still top digital downloads, according to Nielsen figures.

But Bohrman saw a distinct advantage - it costs his label a little over one dollar to produce each tape, while a vinyl run could cost thousands of dollars and take months. With the lower overhead, Burger Records has specialised in signing obscure garage acts for cassette releases.

"You're much more likely to take a chance on music if it's just costing you $5 a tape," he said. And while it is more unwieldy to select tracks on cassettes compared with CDs, MP3s or even vinyl, Bohrman said that is exactly the point. On cassettes, listeners are more likely to take in the whole album.

"A lot of people say that they don't have cassette players anymore, but most of them haven't even tried looking," Bohrman said. "These are the people who let music come to them. You can sit and let Spotify or Soundcloud or Facebook tell you what to listen to, or you can work to find new music."

Even when stores in industrialised countries stopped stocking cassettes, the format remained vibrant in sub-Saharan Africa, meaning that afropop fans are often obliged to look for tapes.

Among genres, hip-hop and hardcore punk lend themselves well to cassettes, said Hope Silverman, manager of Rough Trade's New York store.

"If it's some big, pristine studio recording, it's not well served being on a cassette. That's why hardcore cassettes used to sell so well - it's about that fuzzy, grungy thing," she said.

For cassette day, Silverman co-curated a two-tape set of emerging US and British acts who have a do-it-yourself feel. She said she was struck at the interest level both at her store and the original Rough Trade shops in London.

"It's not going to be like vinyl; it will be a niche thing," she said. "But I think you'll see more people doing it."

She attributed some of interest in cassettes to romantic nostalgia, with music lovers who came of age in the 1980s or early 1990s fondly remembering making thematic mix tapes on old double-deck cassette players.

Chris Pantelino, 43, browsing through Rough Trade's special display of cassettes, decided to buy a tape by dream poppers Wild Nothing. One issue - he has no cassette player. Instead, he puts cassettes on display, while choosing CDs when he actually listens to the music.

"I just like to look at them. Maybe a big part of this is that it takes me back to my youth," he said.

Jose Boyer, singer and guitarist of the New York band Las Rosas which just released a cassette, also had another explanation for tapes: "They're for people like me and my friends who have sh-tty cars."