The Keb' Mo' Band. All photos by KEVIN KINDER, NWA Media.

Legend tells us Robert Johnson sold his soul to the devil to learn how to play the blues.

Keb’ Mo’ never went through such a process, but he proved to a crowd of about 1,000 on a Wednesday night at the Walton Arts Center he’s a capable and even emphatic when he plugs in and plays with abandon.

So, the question becomes this: If people would go to such lengths to play (even if the Robert Johnson story is just a blues rock fairy tale), why wouldn’t you use your power all time?

Keb’ Mo’ — and to a lesser degree, his opening act, Anders Osborne — provided no definitive answer. Keb’ Mo’, real name Kevin Moore, is a three-time Grammy winner for contemporary blues albums. And while he colors all his music with that shade, the first 45 minutes of his set was rather subdued. Included in the first part of the evening were ballads (“Life is Beautiful”) and a slow, folk-tempered song (“We Don’t Need It”) from Keb’ Mo’s newest album, “The Reflection.” The latter, a song about struggling through the recession, never resonated despite how topical it remains.

Two years ago, when Keb’ Mo’ was last in the same venue, he played with sparse accompaniment and a purposely subdued approach. We were promised that context then.

This time around, with a full band behind him, the evening started in much the same way and left me wanting a little more oomph. It would become, eventually, a much different kind of concert.

Chalk up the first half to Keb’ Mo’ and his able backing band needing to warm up for the evening, or for the crowd needing a moment to let their drinks settle and warm them up a bit, but the difference after the hour mark of the concert was dramatic. Even early on, catcalls from the crowd gave Keb’ Mo’ suggestions for songs. When he got into one of those audience suggestions later — “She Just Wants To Dance” — the crowd was already on its feet and dancing, something it did for the bulk of the three-song encore, which found Keb’ Mo’ playing slide guitar blues and playing them well. Meanwhile, everyone in the mostly full venue showed their appreciation.

It was, after all, what they’d came to see.

A note about the opener: Anders Osborne, from New Orleans, faced the formidable challenge of opening for a largely unfamiliar crowd and using only his guitar and voice to do so. As someone said to me during the break between Osborne and the headliner’s sets, “Well, he tried hard.” Osborne set a tone for the evening, although it’s unlikely he or anyone in the crowd knew it at the time. After the fourth of the six songs he would play Wednesday night, Osborne pondered aloud that the evening was a blues night and he should play a blues song. As soon as he started into a slide guitar solo, the crowd collectively hollered in approval. Osborne too was best when he was at his bluesiest.

Keb’ Mo’ set list: 1) didn’t catch this title; 2) Change; 3) Life is Beautiful; 4) Government Cheese; 5) Perpetual Blues Machine; 6) I See Love; 7) We Don’t Need It; 8) More Than One Way Home; 9) Walk Back In; 10) The Whole Enchilada; 11) Shave Yo’ Legs; 12) Soon As I Get Paid; 13) Dangerous Mood; 14) I believe the song was Just Lookin’; 15) The Door;

Encore: 16) Am I Wrong?; 17) She Just Wants To Dance; 18) A Better Man