YOU wouldn't want to get in to a taxonomic tussle with Calexico. It's not that they are in any way sensitive about how they're described, it's just that they've heard so many different category names over the years. "We get 'alt.country', 'Americana' plus 'alt.Americana', 'alt.rock', 'tex-mex' and 'alt.rock tex-mex' together," says lead singer Joey Burns. "We also got a lot of 'David Lynch' and 'Ennio Morricone' and also a fair bit of 'mariachi'. If I was in charge of a record store, I'd put us in the indie rock section. I'd be okay with that. It's indie rock with a large Hispanic following, put it that way," writes Brian Boyd

It makes sense that the two core Calexico members - Burns and John Convertino - live in Tucson, Arizona. The band produce a type of shimmering heat, dust-beaten desert sound complete with a mariachi backing. There's a strange organic purity about what they do; they're the sort of band whose fans smoke roll-ups. A series of acclaimed albums has built them up a not huge but very loyal and knowledgeable fan base in Europe and the US. And, given that their epic, cinematic sound is full of outlaw tales, it's no surprise that Nick Cave is one of their biggest fans.

Burns and Convertino met when they were both members of Howie Gelb's Giant Sand. After a short-lived incarnation as a Tucson lounge band called The Friends of Dean Martinez (who had a serious cult following), they got their new name from an immigrant-friendly crossing town on the California-Mexico border.

It was only with 1998's The Black Light (album of the year for the Wall Street Journal, for what it's worth) thatCalexico first hit the radar screens. A concept album about desert life in northern Mexico, it fairly bristled with raw south-western narratives, with some weird jazz touches thrown in.

Calexico has never really crossed over (although they threatened to with the superlative cover version of Love's Alone Again Or a few years ago). But they are hugely rated by music producers, including, for reasons that can't be fathomed, dance music producers. Andy Weatherall asked them to remix his tunes and Goldfrapp have utilised their services. Calexico's music also featured heavily in the pointless Tom Cruise vehicle, Collateral.

For Burns, the whole Hispanic thing came from his early days doing social work with Mexican immigrants in Los Angeles.

"I'm actually a classically trained upright bass player," he says. "But there was never any way I was going to end up in an orchestra. I was really inspired from early on by playing with mariachi musicians. A lot of these mariachi guys are just as comfortable with acid metal rock music as they are with traditional Mexican music. And it's the same with me. While nominally I'm in an indie rock band, the stuff I really like is Gil Evans, Miles Davis and Charles Mingus."

Perhaps their wilful experimentation has interrupted the band's trajectory. For a jazzhead such as Burns, it's second nature. "You see it so much in this industry - bands make a couple of records that sound like each other and they get a level of success, so they don't tamper with that. I realise it can be difficult for fans to keep up with an ever-changing band, but for us it's the only way to do it."

Garden Rain, Calexico's new album, might well perplex long-time followers. It's a big sounding record, more like a live rock album, that's far removed from anything they have previously attempted. As their record company says: "It is not your average Calexico album, but then again, it never is with this band".

"I'm sort of prepared for the fact that this is going to be called Calexico's rock album" says Burns. "There aren't any mariachi horns on it, and we do pump up the volume a bit. I'm really interested in seeing in whether any of the rock music stations play this record. In the past they've never played us. Their excuse was that we were 'too ethnic' sounding."

The band's purist approach to how their music is recorded sets them at considerable odds with the digital age.

"We are the most analogue band you could ever hope to find. Don't get me started on digital music. First of all, if you look at a sound wave, it's in analogue form, not digital form. Second, look at the sound reproduction. From extensive studies of this I can tell you that if you have a vinyl album with a really good needle, you're looking at close to 100 per cent faithful sound reproduction. Go down to the CD and you're only getting about 90 per cent. And with all these MP3 players around, I think that figure has to go down to about 55 per cent.

"I could talk you under the table about analogue mastering and analogue mixing. I'll spare you. Put it this way: if I had my way, all our music would only come out on 128-gram vinyl."

Watch out for Calexico as they expound on the parlous state of the music industry in the forthcoming documentary Before the Music Dies, which takes a critical and comedic look at the homogenisation of popular music. Commentary comes from Branford Marsalis, Elvis Costello and The Roots, among others. Many questions are archly raised - notably, "Why do they always play the same few songs over and over again on the radio?", "Why do major labels no longer allow musicians to develop their career over time?", "Why do local radio stations no longer feel local any more?" and (tee-hee) "Why is it that all the acts promoted as the 'new thing' seem to resemble fashion models?"

"I think their main findings were that superficiality is in and quality and depth is out," smiles Burns in a told-you-so sort of way.

Calexico's Garden Rain is released today on the City Slang label