As soon as technology becomes obsolete, it starts to gain a special sort of nostalgic appeal. Vinyl records, typewriters, vintage arcade games: we're fond of the detritus of a life that's been left behind, and it's no different with cassette tapes. Just look at the number of tape-shaped iPhone cases and purses you'll find on Etsy, next to the ones in the shape of old Nintendo Game Boys.
Much of this nostalgia isn't wedded to a deeper interest in the possibilities of the cassette tape. But a new generation of tape aficionados is exploring what can be done with this cheap, accessible format, which often lies forgotten in bargain bins around the western world, but which is still wildly popular in parts of Africa and the Middle East.
Brian Shimkovitz is one of those people exploring the new possibilities of cassette tape. An ethnomusicologist from Brooklyn, Shimkovitz attracts about 35,000 readers every month to his website Awesome Tapes From Africa, for which he converts music on cassettes to MP3 and lets users download it for free. Due to the popularity of the site, he now also runs a label, and DJs around the world.
"I've always been a bit of a tape guy," he says. "I was slow to adapt to the CD and I still have hundreds of tapes of various kinds in my listening rotation. I sometimes carry a Walkman on the subway; people occasionally glance at me oddly."
The project didn't just come out of a desire to resuscitate an old format, though. It started on a research trip to Ghana, when Shimkowitz started getting interested in the local form of rap and wanted to share it with a wider audience.
"From what I saw in west Africa," he says, "the widest variety of music could usually be found on tape."
As for the blog, it was just an "immediate and efficient way to get the music out there".
Shimkovitz isn't alone in delving into tapes from around the world and bringing them to new audiences. There are labels such as Sublime Frequencies, based in Seattle, which find music on tape around the world and release it on newer formats in the US and Europe. Sublime Frequencies' big star is the Syrian singer Omar Souleyman, who has recorded with Björk after putting out more than 600 cassette albums, which are blasted from kiosks all over Damascus.
Then there are the western indie bands who put out cassette albums, in Shimkovitz's words, either out of nostalgia, as a gimmick, or as "a genuine continuation of the underground tape releases that music-makers in the noise, experimental and lo-fi pop movements have been doing forever".
This year alone, established rock artists such as Akron/Family, Of Montreal and Dinosaur Jr have released music on tape, while countless other smaller bands made cheap cassettes to sell on tour, or to release on tape-only labels such as Scotch Tapes and Tapeworm.
On top of discovering music from other cultures, recording music cheaply and easily, and being part of a cassette culture that stretches back to the 1980s underground, another reason to hold on to tapes is that they allow us to rediscover music from the past.
Todd Hart, like Brian Shimkovitz, is a blogger who converts tapes to MP3s, but he's based in London and finds all his material in a particular branch of the charity shop Oxfam. Recent posts on his popular blog, Dalston Oxfam Shop, have included music by Sister Irene O'Connor, a nun who released a trippy electro album about God in 1976; an NME compilation cassette from the 1980s, and a tape sold in Ibiza in 1991.
When he started the blog in 2006, Hart says that most DJs he knew "would go to great lengths to trawl the vinyl racks at the Dalston shop for something rare, but never think to look at tapes," he says. "I showed them that you can extract value from all kinds of obscure places."
According to a report published this month in USA Today, music cassette sales were up 37 per cent this year. Although numbers are still minuscule compared with CD, digital and even vinyl sales, the tape revolution is making its own small splash.
Hart says that he often hears of bands putting out limited-edition tapes now, which is something he "never saw" when he started the blog.
Whether it's a fad or, as with vinyl, a long-running obsession, the cassette tape revival has definitely arrived. Just don't throw away your Minidiscs and CDs: they could be the next obsolete formats to have their day in the sun.