Prior to Friday night, more than seven months had passed since the Indigo Girls performed a major, public concert.

“This is not the way we thought we’d see Ameris (Bank) Amphitheatre,” Amy Ray joked as the pair quietly arrived on stage.

“The protocol here has been awesome. It’s just so good to see you all tonight,” Emily Saliers added before the duo kicked off their 24-song set with “Get Out the Map.”

Emily Saliers of the Indigo Girls.

Credit: Robb Cohen for the Atlanta Journal-Constitution

icon to expand image

Credit: Robb Cohen for the Atlanta Journal-Constitution

The Indigo Girls' performance in the parking lot of the Alpharetta amphitheater marked the second weekend of Live Nation’s “Live From the Drive-In” series, which last week brought Jason Isbell and Blackberry Smoke to town and on Saturday, will welcome a sold-out showing from Yacht Rock Revue.

Ray and Saliers also drew a full house – about 500 cars with up to four people per vehicle – and, like last week’s musicians, frequently expressed gratitude to be back in front of fans.

Indigo Girls fans hang out in the parking lot of Ameris Bank Amphitheatre for the duo's Oct. 23 concert.

Credit: Robb Cohen for the Atlanta Journal-Constitution

icon to expand image

Credit: Robb Cohen for the Atlanta Journal-Constitution

Their set, which commenced at exactly 8 p.m., spotlighted several songs from their intuitive new album, “Look Long,” while also rewarding their forever-dedicated fans with chestnuts such as “Land of Canaan,” from their 1987 “Strange Fire” debut and 2006′s “Pendulum Swinger.”

It took a couple of songs for Ray and Saliers, in particular, to find their harmonic sweet spot, but who could begrudge them for taking a little time?

The setup for this show defined simplicity. Two girls (OK, women), two guitars - sometimes swapped out for a banjo or a mandolin – effectively uncomplicated lighting and much introspection and heart.

Of their new material - which Ray and Saliers talked to The Atlanta Journal-Constitution about upon its release in May – a trio of standouts resonated particularly deeply live. “Country Radio,” poignant on record, felt like a true heart-piercer under Saliers' vocals onstage. Meanwhile, Ray’s “S*** Kickin',” the feisty opener on “Look Long,” and the acoustically textured call to maintain ambition, “When We Were Writers,” also landed well.

Amy Ray of the Indigo Girls.

Credit: Robb Cohen for the Atlanta Journal-Constitution

icon to expand image

Credit: Robb Cohen for the Atlanta Journal-Constitution

Both Indigo Girls took an unaccompanied turn - Ray on “Romeo and Juliet,” a fan favorite cover of the Dire Straits song from the duo’s 1992 “Rites of Passage” album, and Saliers with “Train Inside,” a sparse poetic reflection from her solo album, “Murmuration Nation.”

But it’s always the mellifluous harmonizing that defines their music and “Least Complicated” and the enduring “Closer to Fine” demonstrated that no amount of time off from touring can diminish some of the best in their achingly melodic canon.

Though the Indigo Girls remained productive throughout the summer with a slate of livestreams for various charities (the Friday night show was also livestreamed, and will be available for viewing until 8 p.m. Oct. 24) - concerts from your living room can never equate to the thrill of hearing fans reflexively single-clap after the “Hey, la la” in “Share the Moon” or take a verse of “Power of Two.”

As we were reminded again, even in this unconventional setting, live music matters.

Follow the Atlanta Music Scene on Facebook and Twitter.