I’ve read a lot about Cracker over the years, and one thing I’ve never understood is why they’re often referred to as a “straight-ahead alternative rock band”. Maybe because David Lowery’s earlier band, Camper Van Beethoven, was such a nonpareil, and Cracker does indeed traffic in a more agreeably mainstream type of alternative rock. But the term makes them sound so ... I don’t know, generic? Do we so quickly forget this was the same band with a yen for Grateful Dead covers, a bluegrass album called O Cracker, Where Art Thou that paired Lowery and Johnny Hickman with Leftover Salmon, and a version of “When the Levee Breaks” which was rejected from a Led Zeppelin covers album (Encomium) because it was deemed a little “too weird”?

Let’s call them what they were, and are: a country-rock powerhouse with enough soul, crispy R&B, grungy alt-rock, psychedelia and torrid guitar jams to blow past any individual pigeonhole. At a recent headlining show in the packed, toasty downstairs room of Cambridge’s famed Middle East, they stretched out with fullness and vigor, focused as much on more recent songs as hits as if to remind people they did, in fact, survive the ‘90s and didn’t go the way of former contemporaries like Stone Temple Pilots.

The two hour set was a strong and generously apportioned mix from both of the band’s decades, even if the strength of old school crowd-stokers like “Eurotrash Girl” and “Low” meant exposing some of the flaws of Cracker’s more recent material. Lowery’s songwriting is more disjointed and displaced than it used to be; 2009’s Sunrise in the Land of Milk & Honey doesn’t want for strong hooks but there’s something that separates “Low” and, say, “Get Off This”, from the newer “Turn On, Tune In, Drop Out With Me” or “Show Me How This Thing Works”. Maybe it’s smart versus smart-assed? Doesn’t matter, necessarily. Whatever’s changed about the way Lowery and his bandmates assemble a tune these days is forgotten when they turn up a gem like “Friends”. On the album it’s a duet with the Drive By Truckers’ Patterson Hood, and at the Middle East, it’s one of the night’s best-received numbers and for a moment it’s like the wonderfully sardonic, hard rocking Cracker of old. If there are lumps in the shows these days, they can still careen, too. “Lonesome Johnny Blues” was the highlight: still gnarly and full of that Cracker sneer, with lots of pulsing guitar and roadhouse abandon.

That the reconstituted Camper Van Beethoven often tours with Cracker these days makes the shows even fuller: a yin and yang, maybe, or at least a two-part revue with plenty of common threads. I’ll maintain that Camper’s gotten progressively better since its 2004 return, as if the band has learned how to have fun again and be reverent, but not too reverent as to become static. Camper played first at the Middle East, and their set went everywhere, from the necessary Camper touchpoints (“Pictures of Matchstick Men” and “Take the Skinheads Bowling” came back to back, both twisted and delightful) to the snatches of ska, klezmer, jazz and country blues that seem to roar out of nowhere, cook for a few minutes and then dissolve into ... well, whatever comes next. You have no idea, really, but the driver seems to know the way.

Lead guitarist Greg Lisher is a cooler, more subversive axeman than Johnny Hickman; he vests Camper songs with much of their personality, even if it’s multi-instrumentalist Jonathan Segel’s violin that’s often more pronounced. Taken together, the two lead players—plus Lowery and guest steel player/mandolinist David Immergluck—run the gamut between pointed and frothy, their songs sometimes furious country or punk and sometimes a slippery, less definite acid-rock. They’re passionately eclectic and the end of their 80-minute set brought a head-rushing run of songs that hit “Club Med Sucks”, The Clash’s “White Riot”, Black Flag’s “Wasted”, “Shut Us Down” and “RnR Uzbekistan”.

A word on Immergluck; a well-traveled sideman, he augmented both Cracker and Camper as he’s wont to do from time to time, and his liquid pedal steel runs and piquant mandolin made him the night’s MVP, stealing much of Lowery’s limelight. If there’s something that both bands share, beyond being immensely professional musicians doing their best to confound expectations of what a country rock concert should be, it’s a strength in operating as a collective personality, rather than a collection of players given sturdy songs to play with. Immergluck, a guest, had that, too: he was an ace at anticipating what everyone else was doing, and whether soloing or as colorist, his contributions were tasteful, but insistent. A great addition.

At the end of the night came the customary “Cracker Van Beethoven” showcase, where, during Cracker’s encore, members of both bands took the stage together to flex some jamband muscles on Pink Floyd’s “Interstellar Overdrive”. Like the show itself, it felt full, protracted, maybe a little excessive and plenty loaded, but suffered for none of those things.