[jasonfarnon]

" voices capable of the tenor range are rarer."

surely a real bass is rarer? I just assume, as someone completely musically inept, based on listening to the vocal groups on the radio, that a bass contributes less, and can be omitted more easily?

[pclmulqdq]

People at the extreme ends of the spectrum of range are rarer and people in the middle of the range are more common. As it stands, choral bass parts fit better into untrained voices than choral tenor parts. A typical baritone (middle range male voice) can sing choral bass parts well enough, but will find tenor parts relatively strenuous.