Painkiller is omnipresent bassist/producer Bill Laswell’s collaboration with New York free-jazz kingpin John Zorn and former Napalm Death drummer Mick Harris. Given the players’ former associations, Painkiller’s Execution Ground is somewhat predictable, but not entirely uninteresting. The trio’s sound alternates between metal-tinged dub and avant-garde explosion, but neither style is sustained long enough to become involving. Zorn is his usual skronking self, whining in the upper register of his saxophone and sounding like a pissed-off Kenny G when reverb is added to his instrument. For all his bluster, Harris, who’s half of moody hiphop duo Scorn, sounds rather timid here—partially because of the mix, which favors wide cymbals and skinny drums. Laswell’s bass, though, can sound like an assaulting guitar or screaming voice, and he’s the album’s indisputable star. On “Pashupatinath,” his dub rumblings are elastic, yet retain the power of a pummeling riff. The two-CD set’s second disc includes ambient remixes of two Execution tracks which, surprisingly, prove far more effective than the original versions. Painkiller performs Tuesday, May 9, at the Black Cat.