After four albums of fuzzed-up garage-blues, in 2008 it suddenly seemed as if The Black Keys didn’t want to be The Black Keys any more. First of all they roped in Dangermouse to produce their Attack & Release album; that still basically sounded like its predecessors with some extra production flourishes, so they went back to the drawing board.

A solo album was the next port of call, with songwriter, singer and guitarist Dan Auerbach deciding that an album of him singing and playing his own songs would be a change in direction. Along came last year’s Keep It Hid then and, apart from some brief diversions into psychedelic territory, it sounded... like the Black Keys.

Where to next then? How about a rap album? Sure enough, around the turn of the year, BLAKROC arrived, featuring Mos Def, RZA and Raekwon rapping over the top of… that same fuzzed up Black Keys sound. It certainly sounded different, but not through the contribution of Auerbach and his Keys compadre Patrick Carney.

If this all sounds like a bad thing, it’s not. All three of those LPs are awesome slabs of swampy, woozy rock, chock full of songs that play fast and loose with those old blues clichés of reckless women and lawless renegades, and they’ve all helped to establish The Black Keys as the only serious challengers to Jack White’s position as America’s chief old-timey rock and roller.

Now back under their original banner, it seems that Auerbach and Carney have realised that, no matter what other hats they try on, they’ll always be making the same noise, so they’ve decided to revel in it. Brothers is their sixth album, and it finds The Black Keys taking on elements of what they’ve learnt on their journey here, but sticking resolutely to a recipe of guitar, drums and raspy, wisened vocals.

So, there’s a strong soul flavour to the sampled brass and strings that flow underneath the band’s cover of Jerry Butler’s ‘Never Gonna Give You Up’, a track full of yearning and regret, but it’s shot through with the Keys’ trademark ragged rock production.

Elsewhere ‘The Go Getter’, full of spat out, surreal lyrics about “mashed potatoes in cellophane” and “pretty girls in bobby socks”, drifting over the top of processed beats and woozy surf guitar, is perhaps the strangest beast on the record, the kind of song you might expect to hear in a musical adaptation of a Raymond Chandler novel. It scuttles along menacingly in the middle of the album, one of those tracks that only really reveals how strange it is after a few listens.

If there’s one subtle influence on Brothers as a whole, it’s the place that it was produced. Eschewing their Ohio homeland for Alabama’s famous Muscle Shoals Sound studio, the Keys seem to find a sense of soulful stillness on this record. Even on the most conventional songs – the woman-done-me-wrong swagger of ‘Ten Cent Pistol’ or the mournful lament of ‘Unknown Brother’ – there’s a sparse beauty to this album that manages to stop short of becoming too reverential.

Again, if any of this sounds like a criticism, it’s not. Brothers goes straight into the chase for the finest traditional rock album of the year so far, and with a slight trim to its 15-strong run would be a front runner. It seems that after growing slightly disenchanted with their sound, The Black Keys have realised they can’t escape that particular noise that arises when these two musicians play together. For those of us that have enjoyed their slight diversions, it’s rewarding to find them come full circle.