Bearing the name of the hallowed 19th-century American intellectual movement of Emerson and Thoreau dangerously raises the stakes for an improvised music ensemble, as does giving improvisations titles like “The Effects of Selfless Giving” and “The Moment of Being the Sound.” Luckily, on Real Time Messengers (CIMP), The Transcendentalists-multi-instrumentalist Daniel Carter, trombonist Steve Swell, bassist/tubaist Tom Abbs and drummer David Brandt-sidestep the blustery rants and pat contemplative postures plaguing ecstatic jazz. Carter asserts a subtle gravity to the proceedings, particularly with the borderline austerity of his alto saxophone and trumpet. Given Swell’s ability to play it broad, and the just barely sublimated ebullience of Brandt’s propulsion, this could have been a gregarious set. As it is, there is a rigor to the music that is engaging, and even suspenseful at times. Credit the timing of the session, which occurred toward the end of a regional tour. As a result, the music is cohesive but lacks predictability.