Paradoxically, unison is harder for a choir than rich harmony. If intonation begins shakily, the choir usually has a few moments to adjust chords. With unison, failure to match tones becomes immediately apparent. Furthermore, a choir more easily stops than starts. Unanimity of attack generally accompanies unanimity of pitch.
Performances falter rhythmically and in pitch most likely at the beginning of a new section.
However, a choir starts a phrase more easily if that phrase can be linked to a previous one. The Warland Singers put the line out fuzz-free as they wind their way through Howells's modal woods. For those familiar with Penderecki's Threnody , Cello Concerto , or Polymorphia , his Song of Cherubim will probably pleasantly surprise. For me, this is the finest work on the disc - a masterpiece by any test I know. Like most Penderecki, the music gets inside you right away.