Surprises are few and far between in the realm of Tortoise, as anyone au fait with the scholarly Chicago quintet will have learned over the course of six studio albums and countless associated releases. Dub, jazz, rock, electronica: all these and more have been present since the group’s self-titled debut in 1994, accreting to form a canon with few equals, contemporary or otherwise.

It’s taken Tortoise until album number seven, however, to permit human voices to infuse the Tortoise brew, though as you’d expect there’s a twist or two. For one, one of the two songs in question is Rock On, a hit in 1973 for David Essex. Secondly, the singer is Todd Rittman, guitarist of defunct Chicago noise manglers US Maple. Like much of The Catastrophist, the track is otherworldly, superhumanly glossy and rides a thermal of bent funk with few precedents. The contribution of Yo La Tengo’s Georgia Hubley to the velveteen epiphany of Yonder Blue is by comparison the definition of straightforward, albeit dusted with lashings of signature Tortoise glitter.

Elsewhere the five psychonauts of Illinois are on exemplary if predictable form, deftly exploring their chosen galaxy of sound and presenting their findings in the widest, most lustrous stereo you’ll hear all year.