"I PLAY rock'n'roll and that's it. That's all I do and it's all I've ever wanted to do. It's the rock'n'roll that kept us alive," Lou Reed once declared proudly. From the opening moments of this, his 20th studio album, it's clear that he is as in love with the visceral force of crunching chords and whipcrack drums as ever; from the lyrics which follow, it's also obvious that his belief in R'n'R's redemptive power is undiminished.

Don't be fooled by the title, though: Ecstasy is often about agony.

Focusing on the break-up of a marriage (presumably that of Reed and Sylvia Morales), it inhabits a similar emotional landscape to Blood On The Tracks or The Boatman's Call, Reed proves himself just as capable as Dylan or Cave of creating magic through the articulation of loss.

The stall is set out from the first song. 'Paranoid: Key Of E', aside from being a great title, features a guitar riff so dirty Keith Richards would be proud of it and, in common with many of the 14 tracks here, harks back to the atmosphere of 1989's classic New York.

Elsewhere, 'Ecstasy' is a jazz-tinged elegy, where Reed's gravelly tones perfectly mesh with the song's doleful sentiments, while 'Tatters' coasts along gently until a shrill guitar scythes through the song and ratchets the intensity up several notches.

Reed's songwriting has always been all the more devastating for its transparency, and there are plenty of starkly brilliant lines here, including frank admissions of inadequacy ("It hurts to see you sad/And I cannot do better than this" - 'White Prism'), and the image of Lou being ejected from the marital bed to the sofa while, "Our baby stares at both of us/Wondering which one of us to call." ('Tatters')

Unfortunately, he doesn't always keep things so clipped. 'Mystic Child' is conspicuously blunt in the midst of so much razor-sharp material. 'Like A Possum', a marathon overdriven cacophony, may be intended to underline Reed's 'Serious Artist' status, but comes across as hubristic and overblown.

'Modern Dance', by contrast, is the album's highlight. Rolling majestically along on the back of a fluid guitar figure, it's as close as Reed has come in many a year to an unabashed pop song. Not only that: the one-time personification of Factory hipness has some fun at his own expense with the frankly mind-boggling suggestion that "Maybe I should be in Edinburgh/In a kilt in Edinburgh/Doing a modern dance." Maybe not, Lou.

'Big Sky', which brings Ecstasy's 77 minutes to an end, sees the storm clouds lift. Upbeat in every respect, its defiant refrain "Can't hold us down anymore" perfectly encapsulates Reed's notion of creativity as freedom and celebration, as the means of triumph over tribulation.

Now 58 years old, Lou Reed is still one of music's true believers. Ecstasy is a sometimes wonderful, often disturbing album, which is only occasionally sabotaged by the scale of its ambitions. It may be only rock'n'roll, but I like it.