In the five years since Argentine singer/songwriter Juana Molina released Un Dia, her sound has undergone a subtle but distinct shift. On Wed 21 (named for the date she finished the title track, Wednesday, November 21), the intricate layering of electronics, from rhythms to delays and adornments, remains intact, as does her organic reliance on lyric melody. What is immediately apparent is the wider instrumental palette at work. In addition to acoustic guitars and drum machines, Molina employs myriad electric guitars, basses, a drum kit, organ samples, a horn, and more detailed electronics. Her voice still dominates, though. This is true in primary and chorus vocals. Check the lilting, breezy, multivalent harmonies in "Lo Decidi Yo," where they engage a faux Brazilian melody as a mutant forro meets the stretched bossa of tropicalia. Despite rumbling tom-toms, a wandering analog synth, and interspersed electric guitars engaged in a separate dialogue, her voice dictates the song's direction and flow. On the opening track/single, a rhythmic vamp similar to "Pump Up the Volume" is framed by controlled feedback and an insistent polyrhythmic pulse. As the electric guitars kick in, her vocal establishes a breezy, labyrinthine melody that dances across rhythms that embrace samba and cumbia. "El Oso de la Guarda" is quirky in the extreme, with bubbling polyrhythmic twists and turns, wobbly guitars, and voices; only the bassline holds its structure together -- though Molina's guitar, charango, and harpsichord bridge is so intoxicatingly ethereal, one almost wishes it took over entirely. Set-closer "Final Feliz" commences as merely a series of guitar chords that begin to build in tempo and intensity, until they dictate a dominant series of layered rhythms on the six-string, bass drum, hand percussion, and even a saxophone. All that's left is for her to sing above it all in waves and layers, stretching her harmonics; she pays attention to the galloping pace, yet refuses its density; she cruises seemingly effortlessly above it all. As usual, humor is part and parcel of Molina's musical architecture on Wed 21. You can hear it in the whimsy of her delivery and in her numerous, almost incalculable juxtapositions of rhythms and melodies. Wed 21 progresses from her previous recordings, but it's an extension of them, not a departure.