Hailed in some quarters as a back-to-basics masterstroke, derided in others as flaccid and stale, it can be universally agreed that To the 5 Boroughs performed the crucial task of lowering expectations for the Beastie Boys.

Until then, it was expected that each of their new albums would be a radical step forward -- or at least a virtuoso consolidation of strengths à la Ill Communication -- but To the 5 Boroughs was neither; it was a straight-up hip-hop album, not quite like anything they made before yet sounding undeniably familiar.

Its modest success and mixed reviews had the unexpected effect of humanizing the Beastie Boys, which in turn meant they could do what they wanted without having to face the daunting expectations placed on them ever since Licensed to Ill, and The Mix Up, the 2007 follow-up to Boroughs, is certainly not an innovative record, but nor is it a retreat.

It's the Beasties' first all-instrumental record, grounded in soul-jazz, a sound they've been mining since Check Your Head (arguably, even Paul's Boutique had elements of the sound in its samples), as they peppered their albums and B-sides with lazy, hazy funk jams.

Most of these were gathered up on the 1996 compilation The In Sound from Way Out, which undoubtedly sounds similar to The Mix Up, but that's at heart an odds-n-sods collection, bearing the evidence that it was patched together from different sources.

The Mix Up was designed as a specific project, so it holds together better, and it's also decidedly less knowing in its references than the cleverly kitschy In Sound (its title and artwork borrowed from classic '60s LPs).

This is a fusion of sounds -- cool organs, elastic guitars, loping basslines, rolling rhythms -- where all of the elements are integrated together, turning into a style that's recognizable as uniquely, undeniably the Beastie Boys, even if they don't utter a word on this record.

As always, they're more about feel than instrumental acumen, but they've sharpened as players, creating tighter, assured grooves and seamlessly blending their fascinations with funk, dub, soul, and Latin rhythms.

Even if the instrumental interplay is tighter, the overall atmosphere is alluringly warm and friendly: it's music that flows easily and it's a perfect soundtrack for a slow summer afternoon.

Most of all, the Beasties sound relaxed and comfortable, enjoying the process of making this music, and if you're on the same wavelength, it's hard not to get sucked into it too.

The Mix Up is not a major statement, but that's the nice thing about the record: it's as personal and idiosyncratic as any old funky soul-jazz LP that you'd find deep in the crates of a second-hand record store.

It's easy to enjoy and it's indelibly stamped with the personality of the group, which is not only no small thing, it's also a good, rewarding path for the Beastie Boys as they approach middle age.