Ive never been a part of a choir.
Ah, i suppose most people haven't been a part of a musical ensemble of singers. 
yea they are popular at churches
That's true, Churches are the most frequently associated group with a choir, alongside theaters and concert halls. 
oh yea? thats interesting.
During the 18th century, they used the word choir to distinguish between soloists and quartets. 
oh thats cool, makes sense too
Yea, i find the singing in conjunction with one another to be very tranquil.