One of the tenets of post-Cage experimental music that has gained real traction among improvisers is the ability, in essence, to program indeterminacy using computers and MIDI technology. Portuguese flutist Carlos Bechegas creates an impressive variety of sounds using pitch-to-MIDI controllers on Right Off (Numerica), a series of duets with Derek Bailey. Though he plays an unadulterated hollow-body electric guitar, Bailey manages to more than hold his own in terms of producing a continually morphing stream of bracing sounds. As is the case with almost every recording Bailey has made since the mid-'60s, this recording conveys Bailey's urgency to move off the thin ice of the moment. This instinct of Bailey's intensifies whenever Bechegas' sound bank turns either lush or whimsical, like the rampaging carillons the flutist lets loose at one point, prompting some of Bailey's most agitated playing in the set. Still, as is the case with many Bailey duet recordings, the sum far exceeds the parts provided by Bechagas and himself on Right Off, resulting in riveting music from beginning to end.