Musical miscegenation is often how great creative leaps come about. That's essentially what Daniel Lanois said shortly into his set with Chicago's Tortoise.

Musical miscegenation is often how great creative leaps come about. That's essentially what Daniel Lanois said shortly into his set with Chicago's Tortoise. Stressing the importance of mixing it up, Lanois likened the joint outing to the kind of creative give-and-take that has always informed folk music, proudly referring to the collaboration as a kind of gumbo.

Not quite, unless Lanois is thinking of some sort of bland new gumbo where the ingredients never quite mix. What on paper may have seemed like a promising match between one of rock's great studio mavens and a team of fellow studio rats turned out to be something of a bust in practice, for what are in retrospect obvious reasons.

As a producer and songwriter, Lanois mines matters of the heart, pushing the acts he works with into emotional territory and laying himself bare in his shamelessly poetic solo material. Tortoise, on the other hand, occupies much colder territory, their compositions pieced together as both products of and testament to the digital era. These cut-and-paste collages of ideas at their best may move the feet but rarely, if ever, move the soul.

In a lot of ways the collision of these two disparate visions was like watching a quiet battle between the heart and the mind, with Lanois trying his best to coax Tortoise out of its shell but always failing as the group stubbornly refused to loosen up.

On its own terms, Tortoise remains a surprisingly fine live act, its recreations of complex studio compositions coming off as a flurry of instrument swapping and synchronicity. Sure, the group's approach precludes improvisation -- the closest their opening set came to spontaneity was when one of John Herndon's cymbals fell off mid-song, and a dutiful fan fetched and replaced it for him -- but fragmentary tracks such as "Swing from the Gutters," "Ten-Day Interval" and "Blackjack" remain interesting to watch come together, piece by piece, after all these years, even if their execution seems disappointingly set in stone.

After a short break Lanois came out and joined the band on pedal steel for a run through his recent catalog, particularly the instrumental tracks that comprise his latest disc, "Belladonna." Lanois can be an inspiring performer, especially when paired with a drummer like Brian Blade, with whom he shares an almost telepathic bond. But as talented as the five members of Tortoise may be, all lack the soul of someone like Blade, and the group weighed down Lanois like an anchor.

You could still see him trying, though, conducting the group like a producer, asking various members of Tortoise to drop in and out of the songs, telling them when to raise and lower the intensity and even -- gasp! -- encouraging some freeform exploration. But with few exceptions Tortoise handled its duties like neophytes. Bassist Doug McCombs fared best, his dub-wise rhythms well in tune with what Lanois was up to, and when Lanois pared Tortoise down to what he called its "punk members" -- namely Herndon and Dan Bitney -- for a version of the reggae-esque "Frozen" from "Belladonna," the collaboration briefly came to life. Yet there was nothing sadder than watching Tortoise sink Lanois' typically life-affirming now-standard "The Maker" with their utterly swing-free approach.

If the night ultimately proved a failure, at least one can't fault Lanois and Tortoise for trying. But the former's depth (even more on display for an all-too-brief solo set of requests) was simply out of the latter's league. An evening of Lanois' pedal steel would have been magical. As it stood, it served as an occasional palate cleanser for a mostly flavorless stew.