Allman Brothers’ ‘Fillmore’ gets deluxe treatment

As a live-album zealot, the mention of some potentially wonder-inducing archival set gets me going like the old Sears catalog used to do at Christmastime. In-concert releases are something of a rarity these days, but one that has always been on the short list of all-time greats is the Allman Brothers' "At Fillmore East," a double album from July 1971, comprising seven tracks captured in March.

Certain classics are simply more classic than others, and on that side of the ledger you can underline "At Fillmore East." Repeatedly. Live albums are funny things, though. The peak live-album era lasted exactly three years, from 1969 to 1971. You had masterful field reports from before then: Jerry Lee Lewis's "Live at the Star Club," Bo Diddley's "Beach Party," James Brown's hotter-than-Hades Apollo affair, the Kinks' "Live at Kelvin Hall" if we're being cheeky. But these tended to be happy accidents, documents realized by labels looking to make product on the cheap. No studio expenses, one night, maybe some doctoring, and then print those bad boys up.

Come 1968, you had better amps, people were going to gigs to listen to the music rather than scream along with it, and soon we had the Stones with "Get Yer Ya's-Ya's Out!," the Who with "Live at Leeds," and our men of the match, who set out to make a live album not to hold you over between studio sets, but rather because they were better live, and knew it.

The Allmans were never ace songwriters; that is, fine as their songs could be, no one was mistaking any of them for "Visions of Johanna," "Strawberry Fields Forever," or "Jumping Jack Flash." But in the star-crossed Duane Allman — he'd be dead before 1971 was out — and Dickie Betts, the band had two of the finest guitar players of that or any era.

Betts flat-out cooked, reheating the Allmans' blooze-based goulash so that it perpetually streaked flames. And if there has been a finer slide-guitar player in rock history than Duane Allman, I'd like to know who that is. It's one thing to wail at the blues and make it more, at times, up-tempo than rock. But to enfold it all the while in coursing, silvery sheets feels Merlin-esque, and I wouldn't argue that Allman had a touch of a wizard about him.

Now we have "The 1971 Fillmore East Recordings": six CDs or three audio Blu-ray discs comprising the complete run from that week in March, plus an extra show from the venue's closing weekend in June. Residencies are rare in rock, at least as far as official product sourced from them goes. You'd want to check out Hendrix's October 1968 Winterland material to get an antecedent for what goes on here, with set lists being reworked, numbers getting teased out or truncated, new solos attempted, different closing vamps tacked on.

The smoke never clears, no matter what is going on; this is a workshop in sustained adrenaline. An unreleased cover of Blind Willie McTell's "Statesboro Blues" that opens the second March 13 show — that's right, they used to play twice a night — reminds me of one of those old, barnstorming baseball leadoff guys who'd crack a single, steal his way around the bases, and slide into home on a pitch in the dirt, all in like a minute.

You get nearly five of them here, and this was always a song Gregg Allman sang well. I think of him as a poor man's Roger Daltrey; you don't view him as one of the genre's best singers, but he works on you, and works adroitly, the more you listen, and experience.

Another previously unreleased cut, "In Memory of Elizabeth Reed," from the first March 12 show, crosses the spirit of John Coltrane with the essence of "Travelling Riverside Blues" Robert Johnson. The guitars weave in and out of each other; you hear Betts begin a chord, only to be blown away as he chops it up into arpeggios that Duane plays off of or resolves. That's weird. You're not supposed to be able to do that.

But in terms of the "new" stuff, the real ambrosia for blues-rock buffs is the 17-minute performance of "Whipping Post" from the first show on March 13, a morality play interposed with a cadre of guitar solos seemingly from on high. You realize, as you hear these guys navigate through Stygian waters, that this is a bar band so tested, so primed, so loaded for bear, that it's willing to plummet down an abyss simply to prove that it could come roaring back out again.

Gregg Allman and Jaimoe's Jasssz Band perform on Saturday at Boarding House Park, Lowell. 978-275-1829, www.lowellsummermusic.org.