Barcelona's Octante—Ruth Barberán (trumpet, speaker, microphones), Alfredo Costa Monteiro (accordion, objects), Ferran Fages (oscillators, pick-ups), and Margarida Garcia (electric bass)—create what one reviewer calls "a crackling and crunching kind of sound" that's "utterly condensed." The quartet has essentially become "one common music machine" where distinguishing individual instruments becomes nearly impossible. The two extended improvisations (each around 29 minutes) recorded in Barcelona in February 2008 showcase the Barcelona school of electroacoustic improvisation at its most refined. Brian Morton in The Wire describes the music as "softly fractured, elusive, ends and beginnings elided and the tone at times almost disturbingly intimate." Ferran Conangla's mixing gives everything "an intense presence, like something that unfolds unheard and in the head."

One reviewer observes: "It sometimes sounds, on the first of the two long tracks, that all four are deliciously drawing bows across multiple parts of their respective instruments." The second track "begins with more space, more separation of instruments" before gradually "seeping into far, quiet corners, before regrouping for some fine, harsher dronage and skronk."

What makes Lúnula particularly compelling is its access to duende—Morton notes how Fages's electronics "reaches impressively for duende, that untranslatable sorrow/joy/anger/love/death spirit that suffuses Iberian culture and defines Catalan art in particular." One critic memorably describes how this music "copulates with the demons of an unlikely efficiency which transits across the most disgustingly exciting, remarkably abominable clash of instrumental deformations."

Richard Pinnell in The Watchful Ear finds it "good, I like it quite a bit," though he suggests the quartet might benefit from a fifth member. Still, he acknowledges it's "a nice disc to play tonight with all the windows open and just a tiny breeze cutting through the humidity."

For those drawn to the Barcelona school—that distinctive blend of acoustic instruments, electronics, and cultural depth—Lúnula offers 58 minutes of tough, beautiful music where "Monteiro's accordion breathes slightly asthmatically. Garcia's bass acts as a pulse. Fages creates echoing sounds. And all of them are tightly embraced, moving the same sounds around."