With a sound he’s refined through decades of immersion in thrash metal, Testament guitarist Alex Skolnick seamlessly applies his instincts and technique to jazz. Conundrum, his sixth Trio release since 2002, finds him in strong and versatile form with bassist Nathan Peck and drummer Matt Zebroski. Employing a clean, reverberating sound that’s miles removed from bone-crushing metal distortion, he imbues the music with a dreamy, harmonically uncluttered, structurally ambitious quality, apparent on the opening “Unbound” and the title track. But the stylistic departures are many: “Django Tango” pays homage to the late gypsy-jazz master; “Culture Shock” is high-speed bluegrass with a passing Eastern tinge; “A Question of Moral Ambiguity” is a traditional midtempo swinger; and “Gymnopédie” is an Erik Satie interpretation on acoustic guitar, which Skolnick also plays beautifully during the jazz waltz “Dodge the Bambula” and the closing “Protect the Dream.”