If there is a power above, then its spirit went soaring through John Popper’s harmonica Sunday night, and everyone was there to hear it.

From tie-dye to cowboy hats to khakis to wannabe flower children, approximately 2,500 Blues Traveler fans gathered in Stephens Auditorium for an almost four-hour hard-core blues jam session.

Colors of red, orange, green, blue and purple danced across the stage as the audience shouted out its appraisals for Popper and his solos in “Hook,” “Carolina Blues,” “Stand,” “Yours” and “Make My Way.”

For each of Popper’s solos, the audience would let out one roar in unison and then nothing — nothing but Popper’s harmonica filling the air as the audience sat in an appreciative silence.

I was warned by someone who had been to previous Blues Traveler concerts in Ames that each one gets longer and longer. By the end of the night, I was wondering if he meant longer as in time on stage or longer in terms of Popper’s solos.

Contrary to opinion, Popper himself doesn’t make up Blues Traveler. Although his solos are riveting, energetic and even electric, each solo began to get longer and more drawn-out.

Popper began to slowly lose some of his audience who had sat down and begun to look around. Maybe they stopped dancing because they were tired, or maybe they wanted to chill and marvel Popper’s playing, curious about how anyone could have that much air, or maybe they were bored.

Just when you thought he couldn’t go on any longer, he did. Eventually the rest of the band, especially guitarist Chan Kinchla, would come to his rescue and shake the walls of Stephens back to life, and everyone would be back on their feet.

Although it was a show to promote Blues Traveler’s new album, “Straight On ‘Till Morning,” there was a balance between new and old tunes — many were from the band’s fifth and seemingly most popular album, “Four,” and some were unrecognizable by fans.

To make up for not playing “Run-around,” which wasn’t such a big loss, there was a special treat or two for the audience.

For the first time in more than a decade, according to Popper anyway, the band played “Playmatch Blues,” the band’s first song. It allowed for the audience to hear how much Blues Traveler has grown and how its sound has changed in their time together.

There were also a couple of added bonuses. One of which was a superior remix of “The Joker,” done only the way Blues Traveler can — plenty of harmonica, Kinchla on guitar and a bit of Blondie thrown in — putting even Steve Miller himself to shame.

All in all, Blues Traveler put on a superior performance spotlight on Popper’s talents. From harmonica to guitar to vocals, Popper seems to be able to do it all. Unfortunately, the performance didn’t showcase the rest of the band nearly as well.

The band’s performance was also far superior to the opening band, the Michael Parish Band.

This five-member band, which was promoting its new album, “Beautiful Rocks,” sounded like a bluesy, twangy, funked-down version of Blues Traveler.

The audience didn’t seem to give them a warm welcome as faint clapping slowly reached the stage after each song.

The band’s biggest applause was after the last song — whether that was because Blues Traveler was next or because everyone was sick of hearing the lead vocalist say, “you’re too kind” may remain an unsolved mystery.

However, in the end, it didn’t matter how long Popper’s solos were and that a couple of the band’s songs seemed to never end, Blues Traveler came to impress and did just that.