And then there were eight. Over the summer months, Twin Cities vocal group Cantus shed three of its nine members and added two, arriving at a new, permanent eight-man lineup. Does it sound any different?

Yes and no. Yes, because the current roster of four tenors and four basses is more naturally balanced than before. If anything, this lends further subtlety to the delicate interplay of vocal lines and textures Cantus already majored in. And no, because the changes have been made with no apparent cost to the group's ability to create a richly textured body of sound.

That much was evident on Thursday evening, as Cantus opened its new season with "No Greater Love Than This," a reflection on the predations of warfare, and its effect on soldiers and their anxiously onlooking families.

War-themed programs can be heavy going musically, but this one was absorbingly nuanced. A clutch of chirpy recruitment songs — George M. Cohan's unashamedly flag-brandishing "Over There," and the more sentimentally British "Good-bye-ee" — highlighted the fresh enthusiasm with which young men enlisted for World War I, a kind of innocence we may assume is lost forever.

Amid the bouncy, bushy-tailed positivity of these early numbers, there was inevitable poignancy, because we knew what was coming. Clouds began darkening in Leos Janacek's "Ach, Vojna!" where the recruit is already frightened and homesick. His roiling emotions were powerfully registered in a fervid performance that caught the anxiety and defiance in Janacek's music.

Reality checked in fully with a remarkable interpretation of the Bolland & Bolland hit song "In the Army Now," made sinister by the throbbing block-chord underlay to Adam Fieldson's keening solo, and the marching formation adopted by the singers. Bass Chris Foss' Ivesian collage "Songs of War and Protest" plunged deeper into the nightmare of conflict, weaving snippets of well-known pieces into an unsettling harmonic matrix of his own making.

Readings from letters written by soldiers punctuated the evening, and letters sometimes provided the texts set by the composers. Of these, Lee Hoiby's "Last Letter Home" was the standout. The words were those of Pvt. First Class Jesse Givens, killed when his tank crashed in Iraq in 2013.

Hoiby's soothingly contoured music, written in a kind of extended arioso fashion, elicited what was in many ways the performance of the evening from Cantus — tenderly tracing the heart-aching cadences of Givens' final message to his family, and phrasing with immaculate sensitivity to rhythm and meaning.

Melissa Dunphy's "What do you think I fought for at Omaha Beach?" aimed for the same effect in setting pro-equality testimony by World War II veteran Philip Spooner, but its densely interleaving textures seemed somehow to obfuscate the message.

It remained to John Lennon to clarify it. His "Imagine," in Deke Sharon's beautiful arrangement, movingly closed out an evening high on vocal quality, and long on the ability to prompt deeper reflection on the troubled world we live in.

Terry Blain writes about classical music and theater.