Roberto Carlos Lange, the musician known to the world as Helado Negro, rarely goes a long time without releasing new music. Last year, he released the surprise EP The Last Sound On Earth and collaborated with people like Irreversible Entanglements and Vines . A couple of weeks ago, he shared a Sly & The Family Stone cover . Now, he's one half of Helado Tropical, a new duo with Fabi Reyna, who records as Reyna Tropical. She's a guitar ace who was born in Mexico and raised in Texas, and she makes her own records while serving as a touring guitarist in Sleater-Kinney. Lange and Reyna met two years ago in North Carolina, where a friend arranged for them to meet in the studio. One session led to a years-long collaboration. This summer, Helado Tropical will release the self-titled debut album that they recorded across multiple states, sometimes remotely and sometimes in person. Both of them sing on debut single "Tocando," and Reyna plays florid guitar over Lange's bubbling synth-beat.…