Tempered ambition can sometimes be as frustrating as the lack of ambition itself. British-born pianist Tim Harrison leads a sharply appointed sextet on Aria (CAP) that spotlights vocalist Dee McMillen on three tracks. What adds distinction to those songs is that each is an adaptation of an Emily Dickinson poem. “The Judge Is Like the Owl,” “The Saddest Noise, the Sweetest Noise” and “…Till All the Churchyard Rang” mate Harrison’s sure melodies to Dickinson’s words with marked success-so successfully, in fact, that the other, more conventional, quintet performances tend to lose luster in comparison. A shame, since Harrison’s obviously a real talent; both his piano work and compositions balance a clipped, U.K.-tinged formality with a warmer U.S. jazz sensibility. (Hear “Hog Wedding,” “Half Coyote” and “Sunna”) Still, his arresting way with Dickinson’s words cries out for a complete song cycle.