For a band to stay in the public consciousness and often to keep the members from tearing each other apart in studio squabbles, a change in their fundamental sound is practically essential. A lot of bands that stay together for a long time tend to develop their style in a gentle arc over the course of several albums, tours and occasional side projects. Take REM, for instance. That group has been going for three decades with only one personnel shift and their sound evolved the entire time, even the hardest shifts seeming not so drastic in retrospect. Then there are those bands that up and record something so different from their previous work that they might as well be a completely separate group. Whether it's a sign of the band's impending demise or just simple boredom, these stylistic excursions sometimes end up being more interesting than a lot of what made a band famous. Such an album is Blur's 1999 release 13.

Blur spent much of 1990's as the flagship band for the Brit Pop movement alongside other quintessentially English acts like Oasis and Elastica. They wrote deceptively sunny rock songs with cynical sing-along lyrics around the same time America fell in love with Seattle's main musical export, Grunge. It was a sound very much of its time, so when the experimental hodge-podge that was the end of the decade came around, Blur's sound was suddenly irrelevant. Deeper than that, the band itself had a lot of internal tension thanks to the usual culprit: ambitious, bored musicians. Frontman Damon Albarn would eventually flit off to court hip hop and electronic music with Gorillaz and guitarist Graham Coxon had already put out a side project. Searching for something different, Blur went into the studio in 1999 with electronic stalwarts Orbit in the production booth. The result was 13, a strange, bipolar and ultimately beautiful album with noticeably little rock on it.

As the story goes, Orbit gave Coxon free reign on 13, resulting in a lot more texture and non-pop arrangements. The album opens with a pleasant gospel-lite tune, "Tender". It's an unusual but inspired choice for a first track. At that time, Blur was most famous for the bombastic rocker "Song 2" from their self-titled fifth album, so throwing a seven and a half minute campfire song at the top of 13 is a nice way to set a very different tone.

Of course, fans of "Song 2" were probably both delighted and taken aback by "Bugman". It's loud, punky and even more fuzzy than "Song 2", except that it devolves into an abrasive noise track after the halfway point. It's like a postmodern deconstruction of the soundtrack-ready "Song 2" as well as an attempt to kill it entirely.

The most Blur-like song on the entire album is the hit single "Coffee and TV". It's darn catchy with some bitter lyrics and a memorable music video. This track wouldn't be out of place on Park Life and I'm sure it would have been in the Top 10 in 1993. Its purpose on 13, though, seems to be as a last glimpse of familiar territory before the album veers hard into strange soundscapes.

From that point on, 13 is a tug of war between weird, dirty tracks like "Swamp Song" and "B.L.U.R.E.M.I" and sad haze like "1992". Hip hop finds its way into the list, as does post-rock, freaky noise and just plain experimental anti-pop. If there's a point to any of this beyond just not making Billboard Chart music, it's not readily apparent.

Still, 13 is a unique listening experience. It's not actively off-putting like a lot of attempts by rock bands to depart from rock proper. It's more personal and genuinely artistic than the glitchy tantrums of a spoiled pop group. 13 wasn't really a change of pace for Blur, though. It was really just a sign that they were on their way out and had nothing left to do as a band. Graham Coxon left after 13 and Blur recorded Think Tank without him. Really, Think Tank ought to be considered a Damon Albarn solo album, or even a retooled Gorillaz project considering the sound and the personnel.

Taken as a musical core sample of 1999, 13 demonstrates how pop artists and their listeners were temporarily tired of rock. They wanted weirdness and new sounds, and they wanted to sacrifice guitars to make that happen.