Before there was Calexico, there was Spoke. Joey Burns and John Convertino-the rhythm section for Howe Gelb’s Giant Sand and recent refugees of Friends of Dean Martinez-beautifully sculpted an album out of fully formed songs that combined with a collection of atmospheric musical sketches. Spoke quickly evolved into Calexico and, in between albums, Burns and Convertino have continued to throw forth an eclectic offering of low-key self-released recordings that have recently emerged in the form of Tool Box. Selections range from the aptly titled “Lo-Fi Moon,” made on a tape recorder in a barrio kitchen, to the beautifully realized “When Bellows Crack,” resplendent in its aching accordion, seductive vibes, and ringing guitar. This is Calexico at its uninhibited best. Here the guard is down and the music flows with both passion and purpose.