It was a sensation both familiar and brand new when Fitz & The Tantrums filmed a recent performance for public television’s concert series Live from the Artists Den. The show marked a return to their home base for the beloved Los Angeles band, in a truly incredibly venue—the breathtaking Spanish Gothic-style Theatre at Ace Hotel, formerly the United Artists movie palace, built in downtown LA in the 1920s under the hands-on direction of Mary Pickford. Fitz & The Tantrums played its signature dance grooves — blending classic soul and ’80s pop on such songs as the band’s new single, “The Walker” — and, as always, refused to let the invited audience of 900 even think about sitting down.