Perhaps the most marketable band in the USA right now, TLC are usually assessed in terms of their take-no-shit sexual politics, their increasingly adventurous visual image (Girlz In The Hood meets Barbarella), and their private lives (rapper Lisa "Left-Eye" Lopes once burned down her millionaire boyfriend's mansion). If anyone ever bothered seriously analysing the stuff contained on their records, their jaws would drop even further.

TLC's material, for the most part, is located squarely in the buffer zone between uptempo pop-rap and hard R&B/swingbeat. Some of the music on FanMail is breathtakingly innovative and futuristic, an astonishing state of affairs given that it is ostensibly an hour of chart-friendly black pop (the biggest-selling genre in America after C'n'W) and that it has just gone triple platinum across the water.

As was the case on their last album, 1994's CrazySexyCool, every inch of the mix is crammed with strange little nuances, rhythmic twitches and indescribable aural squiggles, as on the astonishing title track, where the vocals are morphed and texturised, while in the background, a de-natured robot voice murmurs snatches of the lyrics.

'Lovesick' constructs a twisted, spindly melody out of the dial tones of a telephone; 'Silly Ho' is built around the weird combination of a gently plinking Oriental xylophones and the sampled cries of what sound like baboons (looks shit on paper, sounds awesome in stereo). The stuttering, stop-start rhythms of 'If They Knew', jerking and faltering around in hypersyncopated triple-time, sound like a drum & bass track in slow motion.

They even send themselves up on "I'm Good At Being Bad', which begins with a mushy balladic intro of deliberate gloopiness before abruptly changing into a metal-plated rap number. Problem is, there are a couple of the aforesaid icky ballads already present on FanMail, which is one of several reasons why it's merely two-thirds of a great record. Tracks like 'I Miss You So Much' and 'Dear Lie' are as far removed from the rest of the record as it's possible to get, so sonically cautious and middle-of-the-road that they could have come straight from a LeAnn Rimes album.

The singing has its fair share of shortcomings, too. Admittedly, vocal perfection isn't as important in American R&B as it is in other genres, but there are times on FanMail where the trio stay in tune only by the skin of their teeth. Tionne 'T-Boz' Watkins, who handles most of the lead vocals, is particularly culpable here.

But for the majority of its 64 minutes, FanMail is yet another shining example of the sort of future-shock funk which the likes of Timbaland, Teddy Riley and Missy "Misdemeanor" Elliott have flooded the American mainstream with over the last two years. Part conventional R&B/soul orthodoxy, part otherworldly cyber-pop, this stuff is (I guess) the blackest music around today, due to the absence of white producers and the near-total lack of white influences.