The rare times you encounter them, eight-piece rock bands are something to behold. You find yourself casting your eyes around the whole stage, wondering whether everybody up there is fully focused, whether anybody’s contribution is getting lost, and even wondering, frankly, whether all this instrumentation is even necessary in a live rock performance.

The Revivalists, longtime New Orleans soul-rock troopers who finally broke through in 2016-17 with the soaring, irresistible “Wish I Knew You,” made a more-than-convincing case for jammy big-bandness at their first-ever appearance at the Moody Theater on Tuesday. Now an eight-piece as of last year’s fourth album Take Good Care, they’re twice as big as the Beatles, four times as big as the White Stripes, and carry dual drummers to boot. Their players seemingly cover every instrument on the planet, including pedal steel and saxophone, and they gave the crowd for an “Austin City Limits” taping more than an hour of a good time.

Man-bun and skinny jeans-wearing lead vocalist David Shaw is a smooth, emotive performer who doesn’t suck all the air out of the stage, and the rest of the band — including guitarist Zack Feinberg, pedal steelist Ed Williams, and saxophonist Rob Ingraham — got opportunities to take their turns in the spotlight without excessive jamming.

Hard to say, of course, how much of the Moody crowd was familiar with the Revivalists’ catalogue beyond the chart-topping “Wish I Knew You,” but there was no sense of impatience waiting for them to finally drop it. Shifting easily between head-bobbers like “You Said It All” and “All My Friends,” and ballads like “Otherside of Paradise,” (all off Take Good Care), they showed they have tunes and live chops to spare. The group’s lyrics don’t often break into any themes that haven’t been explored repeatedly in the past, but they feel fresh enough to not distract from the good time the Revivalists’ playing offers.

When “Wish I Knew You” finally came as the pre-encore closer, it was merely the topper on an 80-minute cake that left you feeling like the Revivalists were one of those bands that were just meant to play ACL Live — able, lively, and, as their name suggests, dedicated to keeping their organic strain of rock ‘n’ roll alive.

(Top photo by Zackery Michael from show program cover)