Much of the greatest Renaissance choral music was written for a handful of voices. The intimacy is not a limitation — it is the point.
Modern audiences often meet this repertoire through large festival choirs of sixty or eighty singers, which is roughly the opposite of how it was conceived. The scale changes the music's nature: what was written as a conversation between independent voices becomes a block of sound moving together.
With a single singer on each line, every strand of the counterpoint stays audible. The listener follows independent melodies weaving together rather than a wall of sound. When a phrase in the alto imitates one the soprano sang four bars earlier, you hear the relationship — which is the entire architecture of the piece.
This music serves a text. The rhythm of the Latin, not a bar-line, shapes the phrase. Bar-lines were largely an editorial addition centuries later, and singing to them rather than to the words produces accents the composer never intended.
Begin with a short motet rather than a mass setting — five minutes of four-voice counterpoint teaches the ear more than an hour of larger forces. Once the individual lines become audible to you as lines, the whole repertoire opens up. How it sounds in a room: performances.