The third volume in Navona’s enterprising ‘Quadrants’ recordings of new music for string quartet gives voice to an intriguingly conservative range of contemporary currents in American music, touched at times by earlier classical traditions, in committed performances by the Altius Quartet, based in Boulder, Colorado.

Despite stylistic differences, the music overall captures a rational sensibility that at times makes it seem as if AI composing machines were at work. Yet there are human touches throughout, as in the absorbing String Quartet No 4 by Phelps Dean Witter, which the composer came up with on his way to the grocery store and which in its last movement hearkens back to Wolf’s Italian Serenade.

On the way to Witter from Bruce Babcock’s affecting, retro-Beethovenish The Present Moment, the Altius encounter Nora Morrow’s endearing Rose Moon, named after the composer’s mother, in the form of three homespun dialogues filled with lovely lyrical things for the four players to do, especially the cello. Gary Smart’s Three Fantasies on African American Songs takes a different, more biting tack, finishing with a ghostly, skating take on ‘Shortening Bread’.

Written as a speedwriting exercise, Jonathan Newmark’s Tom Dooley without the Fringe on Top channels the energy and rhythms of Bartók’s Fifth Quartet. Alastair White’s Two Panels is a passionately atonal essay about time. Janice Macaulay’s Three Pieces creates an arresting playground of sounds and effects. Beth Mehocic’s Picasso’s Flight recounts the failed efforts of the composer’s pet parrot to fly.

Recorded at the University of Colorado’s Grusin Hall, the sound is precise and clear.