Metallica's reissued 1982 demo tape "No Life til Leather" on cassette. 
Metallica's reissued 1982 demo tape "No Life til Leather" on cassette.  - 

Music fans, who like to impress their friends with their collection of vinyl records, might feel out of step with hip people who are tuned into cassettes, which have made a such a big comeback that manufacturers cannot keep up with demand.

Artists like Justin Bieber, Eminem and Metallica have all put out material on tape recently and the blockbuster film, “Guardians of the Galaxy” not only put a hero center stage with a Sony Walkman, but has also sold 11,000 cassette tapes of the film’s soundtrack.

Sales of cassette tapes are booming in America and the U.K., where they are at their highest in 10 years, according to the industry group the BPI.

"We set up duplicating audio cassettes in the mid-'80s, we took in the boom of the '90s and then it all went quiet. Everybody disappeared but we stayed in there,” said Alan Williams, who runs Tapeline, the last remaining cassette manufacturer in the U.K.

Williams said there is a bit of nostalgia involved, "a bit of trend, it's the in thing at the moment. A cassette version of an album, play fast forward, rewind, that type of thing. Probably 10 to 20 percent bigger sales this year on the whole," he said.

The revival of music on cassettes is making the small plastic cases with a thin ribbon of tape cool again. "I absolutely adored cassettes," said Trevor Nelson, a soul music disc jockey with a popular program on national British radio.

"Cassettes gave me liberation. I remember getting my first Walkman aged 15 and ultimately I don't think I would have become a DJ, because I actually made mix tapes and playlists for people," he said.

Of course the nostalgia is tinged with cool references to the culture of taped music, where for the first time people could record their favorite songs off the radio and make their own mix tapes. "For me cassettes were always vectors of discovery, love and friendship," explained Kitty Empire, the pop music critic at the U.K.'s Observer newspaper. "I still have compilations made by friends and former flames," she reminisced, "evangelizing by cassette still feels that little bit more personal than sending someone a link to a playlist."

It may be a modern fad driven by baby boomers who secretly kept their collection of vinyl records and cassette tapes, despite the introduction of compact discs and the growth of downloading and streaming in the digital age, but the industry has taken notice.

"We still put out tapes because it's an affordable way to put out music, for an artist in a climate of increasing and excruciating vinyl costs," said Matt Flag from the record label Beat Concern. "I think they look nice, they sound great and they can be made in small quantities for very little cost," he said.

The biggest maker of cassettes in the U.S. is National Audio Company, which orders its plastic shells from factories in China and Saudi Arabia.

The company has about 50 workers, including recording engineers and graphic artists, assembling up to 100,000 pre-ordered tapes a day to satisfy demand for a product that until recently may have seemed obsolete.

Last year, National Audio sold about $5 million worth of cassettes, a 31 percent increase in sales from the previous year.

Seven in 10 of its clients are independent labels and largely unknown bands, but a number of industry majors are jumping on the bandwagon, such as Sony, Capitol, Disney, and Universal Music Group. It may be driven by cost, nostalgia and novelty value, but cassette tapes are once again having their moment.