Sure, they sound good on the radio, but how are they in concert?

It's a question that comes up often with bands played on 89.3 the Current. The adventurous public radio ­station is usually way ahead of the curve in discovering hip new acts, but it can also throw out unproven groups that are way behind in the live realm. Case in point: The station is still living down its selection of MGMT to headline 2010's Rock the Garden concert.

At its ninth annual birthday parties Friday and ­Saturday at First Avenue — consistently one of the biggest all-local music events of the year — the Current picked eight Minnesota acts off its play­list and put them to the test in front of packed crowds. Five of those acts were relative newbies, and two others, Har Mar Superstar and Caroline Smith, reinvented themselves last year with more soulful R&B sounds.

Har Mar certainly came on strong in the headlining slot Friday, but the real ­superstar of the first night was his backup singer, Lizzo. After making a local splash with her trio the Chalice (including a set at last year's Current birthday bashes), the real-life Melissa Jefferson is now riding an international wave with her solo debut, "Lizzobangers." The album earned her oodles of local acclaim, an indie-blogger buzz and now a budding U.K. following (she had only just returned from a London festival on Wednesday and goes back next month).

Lizzo commanded the stage from the get-go on Friday, starting with the meet-the-new-boss opener "W.E.R.K., Pt. II" and culminating with the racially charged "Hot Dish," in which she self-edited the provocative but profane lyrics for the show's live broadcast. At once playfully sexy (with frequent hair flips and sashaying dance moves) and heatedly powerful (with a gnarly, Missy Elliot-like rapper delivery), Lizzo's set packed extra punch with the help of her record's producer Lazerbeak and drummer Ryan McMann as well as a not-so-surprising appearance by her other all-female group, GRRRL PRTY.

She sings, too. Lizzo added a savory she-bop spice to an expanded Har Mar Superstar lineup featuring Solid Gold/Gayngs bassist Adam Hurlburt and the well-received retro-soul songs from last year's throwback album "Bye Bye 17." A sign of the sex-schtick emperor's new clothes, Har Mar (Sean Tillmann) didn't strip to his underwear like he always used to do and had the crowd dancing in thick winter wear during the Motown-flavored bouncer "Restless Leg."

Lizzo was the belle of the Current’s birthday bash on Friday night, performing her solo material as well as with her group GRRRL PRTY.

Friday's opening band, Actual Wolf, had the loudest and most ambitiously arranged set of the entire party lineup. Frontman Eric Pollard's folky twang-pop songs such as "Kerosene & Spark" took on a dramatic new flair with guitar work by not one but two local aces, Jacob Hanson and band newcomer Erik Koskinen. Not faring as well was '80s-flavored dance-pop quartet Strange Names, which nailed the buoyant harmonies of its single "Luxury Child" but sounded stiff and off-pitch while debuting new songs. Less tight pants might have loosened the lads up.

Strange Names' Liam Benzvi at least came up with the best crowd-pandering line of the parties: "I'm Whoopi Goldberg, and you're my 'Sister Act.' "

As Saturday's headliner, the slender and long-legged Smith provided a physical antithesis to Har Mar, and a very different kind of sultry R&B sound, with equal hints of Carole King and Beyonce. The former acoustic folkie suffered some haphazard and lagged moments in her biggest local gig to date, but when she was on, she was on fire. Her brightest turns came during the slower-swaying, soul-searching anthems "Half About Being a Woman" and "Child of Moving On.".

Preceding Smith on Night 2, boys-to-just-barely-men indie-punk quartet Howler proved to have gone through its own sonic metamorphosis, albeit not as dramatic of one. With a new, New Zealand-reared drummer in tow, the college-age Minneapolis rockers added harder-blasting, darkly fuzzed-up guitars and feistier rhythms in a blustery set made up mostly of tunes from their sophomore album due March 25. The Ramones-y "Drip" and new single "Don't Wanna" sounded more like the work of a full-time band than just the clever bedroom musings of frontman Jordan Gatesmith.

Saturday's lineup kicked off with two yin/yang extremes of the Current format. Everlys-like country harmonizers the Cactus Blossoms opened with the most old-school, hard-core twang set ever heard at any of the station's parties, a rarity at First Ave these days, too (and very welcomed by the crowd). Local rap pioneers Heiruspecs — who proved their stage prowess as a live hip-hop band a decade ago — reiterated their current, Current-ready formula with especially rocky tunes such as "The Pushback."

"We're just trying to bridge the gap between Cactus Blossoms and Howler," Heiruspecs rapper MC Felix quipped.

Nine years in, the Current audience didn't blink at any of the musical changeups.

Chris Riemenschneider • 612-673-4658