Richard Glover's compositions, as presented on the aptly titled Logical Harmonies, fall squarely within the tradition of process pieces, following the harmonic structures of Alvin Lucier at times but more often being a direct descendent of the incessantly mathematical works of Tom Johnson. The seven compositions for solo instruments, mixed trio and septet work in what is now a time-honored tradition of establishing a series of constraints and then simply pushing the music and letting it go.

The disc is bookended by a nice pair of brief piano pieces, both played by Philip Thomas and bearing the album's title. Those and Contracting Triads in Temperaments from 12-24, played by Bob Gilmore on electric keyboard, most show Glover's hand. The sequences of isolated chords with systematic progressions call to mind Johnson's The Chord Catalogue and Music for 88, but Glover does it without the footnotes. In his case, they are merely suggestive.

Beatings in a Linear Process is a nice, wavering drone for clarinet, violin and cello, played by Ensemble Portmantô. Here, even with the prolonged and shaky tones, Glover is unabashed about his love of harmony. The certain, and sometimes uncertain, triads make for an uncommon and rather becoming listen. This and the other trio piece, Cello with Clarinet and Piano, are each a mere, give-or-take six minutes long, which points to a shortcoming in the whole of the program. It often feels as if Glover is willing to make his point and move on rather than allow for full immersion into the bath he's drawn. The cello trio sets up a sequence whereby the lead issues a beat about every four seconds, which the other instruments follow. The sustained notes grow longer and, as they do, the voices fall closer and closer to unison. Despite the gap between the pieces, it falls neatly into Imperfect Harmony a contrabass solo beautifully played by Dominic Lash. At ten and a half minutes, it's the longest piece on the disc, and it follows along at a pace close to the cello trio. Listening to the two as a small suite, the effect is not just a little like a tugboat appearing out of a dense fog. It also suggests what Glover could do if he broke the quarter hour mark. Ensemble musikFabrik — stalwart interpreters of Olga Neuwirth and Wolfgang Rihm — play Glover's Gradual Music, another nice layering of extended tones which at nine minutes (curiously given the piece's title) could go on much longer and be all the more effective for it.

The disc comes with a folded insert depicting eight color wheels in a grid with the center square left blank. If the wordless page is to be seen as liner notes, it's a curious suggestion. Glover compositions are too fixed in their chromaticism to be seen as spectral (they are, in a sense, not polychromatic enough!), but then the color wheels aren't gradated either. Glover seems to have found a nice place between worlds in which to float. One can only ask to be left to float longer.