It was a steamy July night in Milwaukee when I first saw Spyro Gyra, back in 1981. Sypro Gyra — the group that had those nice, Caribbean-tinted tunes on the radio — erupted into a wild, irresistible storm of jazz fusion that night. Sheets of warm rain started pouring down on the audience, but a couple of thousand of us who were dancing on tables were soaked already.

Spyro Gyra played five encores that night. They might still be playing encores for that show now, except that the police finally shut them down. When my feet stopped moving, about three days later, I had to wonder: Did those guys play like that every night?

Friday, at the Maine Center for the Arts, I found my answer. No. They play better — and hotter — now.

They don’t jump around as much as they used to, and they only played one encore. They don’t do any rock-star schtick, and after 14 years on the road, they are starting to look a little thirty something.

But on stage they infuse their ballads with bebop and Latin rhythms that make it difficult to stay seated, and their dance tunes blast off into a dense, feverish orbit.

If only the Maine Center for the Arts had tables.

What is even more satisfying is that there is more musical substance than frenzy behind Spyro Gyra’s instrumental onslaught.

Saxophonist and lead man Jay Beckenstein, who renamed the group “Spyro Gyra featuring Jay Beckenstein” last spring, still offers the lush, lyrical sound that most people associate with the group. But more and more, he pushes his solos to the technical and harmonic limits, giving new songs a link to traditional jazz and giving the group’s older songs a new edge.

Friday’s show offered the best of those songs, too. Spyro Gyra played the two most memorable cuts off their latest album, “Fast Forward” — bass player Oscar Cartaya’s “Para Ti Latino” and percussionist Dave Samuels’ “Bright Lights.”

The show opened with “Heliopolis,” an adventurous piece off their 1977 debut album that leaves the group plenty of new avenues to follow even after 14 years. The encore — could it be anything else? — was a sizzling version of the group’s best known and much beloved song, “Morning Dance.”

Keyboardist Tom Schuman, the most excitable and least predictable member of the group, bounced, twisted and pounded his way through an exhausting version of “Schu’s Blues.” He had the audience laughing when he opened the number with eerie, computerized strains of “The Sound of Music.” He had people wondering when he wandered off into rhythmic abstractions, but finally he had them clapping and tapping when he landed back in the 12-bar blues theme that somehow held it all together.

Cartaya got his own standing ovation midway through the show when he did just about everything one can do with an electric bass and 10 fingers, and Samuels spiced his marimba and vibraphone solos with some of the most quirky and interesting beats of the night.

All of which leads to another question: What will they sound like 14 years from now?

Friday’s concert opened with a set from Acoustic Alchemy, an amiable and competent guitar duo from Britain that proved to be a crowd pleaser. Their unaccompanied ventures — a “Sweet Georgia Brown” jam and a tune of their own — showed that they can make their guitars sing.

Unfortunately they played most of their music with the World’s Loudest Rhythm Section. Amplified for a stadium, this uninspired quartet obscured the guitar work, while dutifully, twice a measure, firing off a thump that felt like a fastball to the solar plexus.