Sparklehorse / Mazzy Star

Union Chapel, London

Playing to an audience who are sitting in the pews of a high-vaulted house of worship sets constraints but offers a performer a choice. Do you give nothing away, inspiring reverence in your disciples, or do you try to create a low-church intimacy?

Mazzy Star are very keen on their own enigma. From the moment she walked on stage on Monday night, singer Hope Sandoval's body language was all affected bleakness. Her voice is distant but soulful, and the melodic line of the songs carried unresolved tensions, expressed in repeated arpeggio figures, distorted riffs and brooding organ. At best, the effect is haunting. Mostly, though, it's just languorous - soporific rather than trance-like, and overlain with a mumbled mantra of a half-remembered shopping list.

Sparklehorse's Mark Linkous doesn't need to prove that he's seen the darker side of life. He still walks with a stick months after a cocktail of sedatives and anti-depressants led to a cardiac arrest, yet his songs are bewitching and unmannered.

He sat on a chair centre-stage throughout, wearing a pale cream suit and a hat that left his pallid face obscured by shadow. The slow shuffle of "Weird Sisters" took us straight into the heart of Linkous's bizarre cosmology, his voice fragile and exposed.

His influences are eclectic, but don't suffocate the songs. You can hear echoes of Big Star's gleaming melodies in "Rainmaker", or Gram Parsons' lyricism, or Linkous's debt to country music - but it never descends to a pick 'n' mix pastiche.

Linkous is the latest artist in the tradition of crafting heartfelt, poignant, even naive pop tunes. When his voice cracks on lines such as "I'd like to tell you how I feel", you believe him; there are no pretensions in these lyrics that lay him bare.

In their short set, Sparklehorse were equally at ease with cathartic 60-second frenzy, the pretty waltz of "Homecoming Queen" or more disconcerting soundscapes - clanging metallic percussion and shrill trumpet over double- bass driven rhythms. Their final number was the first live performance of "Cow", its disturbing imagery - "lighting cigars on electric chairs" - and urgency building until Linkous was bent double over his guitar, teasing out feedback. A single spotlight played on the mic, and Linkous, as if in blessing, played fragments of digitised voices to the hall.