What is a bass player?

On night one of two evenings of sold-out shows consisting of four musicians comprising two bands, the Belly Up became a stage for dynamic duos.

Warming up the crowd was the Irish acoustic guitar-and-drum bundle Ryan Sheridan. Their full sound of fast-paced guitar strokes and dynamic drum licks gave you a taste of what was to follow on a night that would leave you asking, What is a bass player?

From Budapest to San Diego, the brother-sister guitar pair Rodrigo y Gabriela played their final performances from a 52-show tour before heading back to their hometown of Mexico City. Showing no signs of travel fatigue, their set opened with a guitar flurry played with fury. Rodrigo and Gabriela’s intertwining guitars rumble, tumble, and muddle the senses forcing you to stomp your feet along with Gabriela’s guitar smacks that mimic a drum; the effect paints a picture of bulls forcing their way through a crowded forest. Most bands of this style need seven musicians to achieve the dynamic sound that these Mexican guitar heroes produce with only two.

The audience was involved, clapping and stomping to the beat, cheering at every moment they could, and even taking to the stage, which became a dance floor. Although most of the set was of the blistering rhythm of flamenco, there were signs of delicacy. All eyes were fixated on Gabriela as she elegantly picked and ripped through her solo rendition of “Aula Magna.” The gradual build had everyone soaking in silence before dipping into a funk that forced everyone to smack their hands together.

Shying away from their originals, Rodrigo confessed an idea that had probably been on his mind all night, “We’re going to play some fucking metal.” The duo shredded flamenco fire on Megadeath’s “Holy Wars” and then inconspicuously transitioned into Metallica’s “Orion” and proceeded to slay “For Whom the Bell Tolls,” giving the night extra grit.

Ending the show with appreciative thanks to the audience and their sound crew — addressing the crew by their full names — gave the night a certain intimacy that is missing from concerts.

• Concert: Rodrigo y Gabriela
• Date: August 15
• Venue: Belly Up
• Seats: GA