Fat Freddys Drop, Somerset House, London

There's something about New Zealand's Fat Freddys Drop which is missing - and it's not just the apostrophe from their name.

Their debut album, 2005's Based on a True Story, is certainly a soulful and groovy entity in a curiously detached kind of way. It's feng shui reggae or Zen dub in its everything-in-the-right-place, stripped-down take on Jamaican music, yet it just doesn't quite hit the spot. So I'm curious to see if their music will spring to life in a live context. And the open-air square behind Somerset House seems like the ideal setting.

When the bass drum on the opening "Ernie" makes my trousers vibrate, it's immediately apparent that at least they've found a way to transpose their lounge sound into a live context. And when the song shifts seamlessly into Eurythmics' "Sweet Dreams", which gets an enthusiastic cheer, it's clear they know how to keep an audience happy.

The brass section (trombone, trumpet and sax) are admirably restrained when they need to be and deliver perfect, economic solos when things start to heat up. And those uncluttered arrangements are the perfect foil for Joe Dukie's smooth crooning as he stands there stock-still, looking cool in a black shirt and matching sarong, treating his microphone as if it were an intimate confidant.

Dukie's voice has been compared to Bill Withers' but he's not quite there yet. It's pleasing enough, almost clarinet-like in its purity of tone, but he doesn't have Withers' range or emotional nakedness. Sting in pensive ballad mode more readily springs to mind.

As the evening goes on it becomes obvious what that missing thing I mentioned earlier is. It's not Dukie's restraint - that's his style. And it's not the band's preference for the slow- to mid-tempo tune. The real problem is Fat Freddys Drop are in search of a drummer, even if they don't realise it yet. At times they nearly took flight during their two-hour set (the rock-steady "Roadie" when 500 arms waved from side to side being a case in point) but those without-momentum, leaden loops prevented them even getting out on to the runway. Immaculately programmed beats can only get you so far because they never go anywhere apart from round in circles.

And it's surely not a good sign that during their one-song encore - their most well known tune "Midnight Marauders" - I found myself looking up at the spot-lit windsurfing seagulls above, rather than at the band. So find that drummer, guys, please - and then you really could be a live band to contend with.