In 1977, Lynyrd Skynyrd suffered one of the greatest disasters in rock history when their plane went down in Mississippi: frontman Ronnie Van Zant, guitarist Steve Gaines, and background singer Cassie Gaines all died in the crash. More than a decade later, the surviving members of the legendary Southern-rock band replaced Ronnie with his little brother, Johnny, and put out the comeback disc 1991 (Atlantic). They’ve been at it ever since, and now they’ve made it all the way to the 30th anniversary of their 1973 debut, Pronounced Leh-nerd Skin-nerd (MCA), which included a little song called "Free Bird."

To celebrate, the group have just released Vicious Cycle (Sanctuary), their sixth studio album with Johnny and their first in four years. What’s more, the anniversary falls in the middle of a good-luck streak: last summer, their epochal "Sweet Home Alabama" was featured on the big screen in the Reese Witherspoon blockbuster of the same name and also in Eminem’s 8 Mile. Around the same time, Georgia’s Drive-By Truckers took the rock underground by storm with Southern Rock Opera (Lost Highway), a rousing homage to the original Skynyrd. When Vicious Cycle came out a few months back, it went all the way to #30 on the Billboard albums chart — the best showing of any Skynyrd album since the plane crash.

The band’s recent success hasn’t come without hardship. During the making of the new disc, bassist Leon Wilkeson, who was just 49, died (the reported cause was chronic liver and lung disease). His death leaves guitarist Gary Rossington and keyboardist Billy Powell as the group’s only remaining original members, but the three-guitar foundation was consolidated three albums ago with the addition of Southern-rock veterans Rickey Medlocke (Blackfoot) and Hughie Thomasson (the Outlaws). Thomasson’s old Outlaws bandmate Ean Evans takes over on bass, and Damn Yankees drummer Michael Cartellone is also aboard. The nine-piece firing squad is rounded out by background singers Dale Krantz Rossington and Carol Chase. They kick off their US summer tour this Saturday at the Cape Cod Melody Tent in Hyannis, then return to Massachusetts on July 27 for a show at the Tweeter Center in Mansfield.

Increased visibility is one thing, but albums don’t sell without a strong single behind them, and the new country-pop ballad "Red White and Blue" is the prettiest thing Skynyrd have done in years. "My hair’s turning white/My neck’s always been red/My collar’s still blue," sings Johnny over a gospel-tinged piano accompaniment. There’s a frenzied guitar shoot-out at the end, and the song starts with a priceless good-old-boy crack: "We don’t have any plastic LA friends/Ain’t on the edge of those popular trends/Ain’t never seen the inside of that magazine GQ." It seems less like classic Ronnie than like something more appropriate: what the fallen star might have sounded like in old age.

"Red White and Blue" is a family affair: Johnny wrote it with the middle Van Zant brother, 38 Special frontman Donnie, and country-pop youngsters the Warren Brothers. And though it may take some rock fans by surprise, the track’s Nashville feel is no accident. That’s where Skynyrd’s management is based, and they recorded Vicious Cycle at Cartee Day Studio on Music Row. Most of the new songs were written by Johnny and the three guitarists, with two primary collaborators: Boston drummer-turned-roots-rock singer/songwriter/producer Tom Hambridge and Survivor guitarist Jim Peterik.

That’s an odd couple if ever there was one, but the album’s supercharged honky-tonk hooks speak for themselves. The opening "That’s How I Like It" adheres to a time-tested formula that’s produced many a Skynyrd classic: catchy roadhouse anthem with swampy blooze undertow. "Like my women hot and my beer ice cold," sings Johnny, hooting and hollering throughout for good-time emphasis. Guitars jangle and crunch before one of them lets loose with a raunchy rock solo that’s as rudimentary as the band’s lifestyle. On the closing "Lucky Man," they all go acoustic while Johnny looks back on his life and decides that despite all the pain, he likes what he sees.

The good vibes continue in between, especially on the rollicking Hambridge numbers. "Don’t you worry how long I’m gone/I come back every once in a while," eternal bad boys Johnny and Ricky Medlocke sing on the lazy boogie duet "Pick ’Em Up." Best known for his work with Susan Tedeschi, Hambridge brings the same kind of blues-pop fun to his work with Skynyrd. "Mad Hatter" is a smoky tribute to Wilkeson, and "Rockin’ Little Town" is a horn-driven rocker that pledges allegiance to the band’s dedicated fans.

Peterik’s contributions are also a blast, but for reasons that have less to do with Skynyrd’s legacy than with who they are today. Medlocke is a flashy guitarist who went platinum with Blackfoot only after integrating pop metal into his honky-tonk, and Cartellone’s bombastic drumming is unchanged from his arena-rock days with Damn Yankees. Which means the band sound great playing new songs by the guy who wrote "Eye of the Tiger." On the standout power ballad "Crawl," Johnny proves he can do mushy love songs with as much conviction as he does rebel yells. The soul-powered shuffle "Hell or Heaven" showcases the group’s female background singers while addressing a subject that’s more up Johnny’s alley: mortality.

Not everyone digs Vicious Cycle as much as I do: Rolling Stone gave it one star and attacked "Red White and Blue" for its right-wing politics, which don’t get more articulate than "If you don’t like it, you can just get out." Skynyrd were never politically correct in their heyday, so it doesn’t make much sense to expect them to be now. But their songwriting chops are still there, and their new-found country-pop and hard-rock influences suit them well.

SKYNYRD AND THE ALLMAN BROTHERS BAND will be forever linked in history, not only for inventing Southern rock but also for the untimely deaths of their spiritual leaders. The Allmans had just two studio albums to their name in 1971 when legendary guitarist Duane Allman died in a motorcycle accident in the band’s home town of Macon. And that was followed a year later by the motorcycle death of bassist Berry Oakley not far from where Duane was killed. The band soldiered on for 10 years with frontman Gregg Allman and guitarist Dickey Betts at the helm, only to break up at the dawn of the 1980s. In 1990, they returned with new guitarist Warren Haynes and a new disc, Seven Turns (Epic). Now, the seasoned road dogs hit the highway once again, reaching out to a younger audience on the collegiate jam-band circuit.

The Allmans have never sold as many albums as Skynyrd, but their recent run has earned them one thing their Dixie brethren have yet to receive: formal recognition from the music industry for their pioneering efforts. In 1995, the group were inducted into the Rock and Roll Hall of Fame; a year later, they won the Best Rock Instrumental Performance Grammy for the version of the classic "Jessica" that appeared on An Evening with the Allman Brothers Band: 2nd Set (Epic).

Freshly canonized, they were thrown into disarray. Haynes and bassist Allen Woody left to focus on their hard-rock side project, Gov’t Mule, and were replaced by young guns Derek Trucks and Oteil Burbridge, respectively. The year 2000 was the most tumultuous one in the band’s recent history: Betts was fired in the spring and Woody died a few months later. Once everyone’s wounds were licked, Haynes was playing with the Allmans again, and they made plans to record a new studio album.

The resulting disc, Hittin’ the Note (Sanctuary), is now their biggest hit in more than 20 years, and that’s a good reason to catch the band on their annual summer tour, which stops by the Tweeter Center next Sunday. What do the Allmans sound like without Betts? On their new single, "Firing Line," they sound the same way they usually did with him — pretty damn hot. Haynes kicks the track off with a struttin’ blues-guitar hook, and the three drummers — Butch Trucks (Derek’s uncle), Jaimoe, and Marc Quinones — settle into a rattling funk groove. Gregg Allman adds the spiky clavinet accents, and before long he’s singing a familiar tune: "Hey now, baby/Don’t you think it’s high time/To change your life’s direction/Get off the firing line."

Unlike Skynyrd, who are a feisty rock band playing pop songs, the Allmans are an electric-blues band with a jazzer’s ear for improv, especially now that pop guy Betts is gone. The Gregg Allman/Haynes collaborations "High Cost of Low Living" and "Old Before My Time" are close relatives of Gregg’s signature tune, the unadorned acoustic lament "Midnight Rider." On the despairing jam "Desdemona," the frontman’s dark organ vamps set the tone for several lengthy guitar runs: throughout the album, Derek Trucks provides most of the Duane-style slide-guitar flash while Haynes continues to push his own quirky rock style into the outer limits.

The band kick up their heaviest groove on the Gov’t Mule standard "Rockin’ Horse," and their cover of the early Rolling Stones hit "Heart of Stone" features the disc’s most lyrical guitar leads. On the 12-minute jam "Instrumental Illness," Burbridge’s propulsive fusion bass line lights the way for Haynes and Derek Trucks, who play a humorous game of call-and-response that nods to the Allmans classic (written by Betts) "In Memory of Elizabeth Reed." "Firing Line" aside, Hittin’ the Note is not exactly a treasure trove of memorable new songs, but the group interplay is as sophisticated as ever. Like Skynyrd, the Allmans are no mere nostalgia act.

Lynyrd Skynyrd perform this Saturday, July 5, at the Cape Cod Melody Tent; call (508) 775-9100. They’re back on Sunday July 27 at the Tweeter Center; call (508) 339-2333. The Allman Brothers Band perform next Sunday, July 13, at the Tweeter; call (508) 339-2333.