What is a clarinet choir?

A clarinet choir is a clarinet ‘orchestra’ but is more akin to a vocal choir in that the sounds made by the different sizes of clarinet blend together rather than being contrasted as with an orchestra. Of all the woodwind instruments, the clarinet has the biggest range of notes and produces a variety of tones throughout its playing compass.
 

It is most suited to large ensemble music not only because the warm tone of the clarinet blends together well, but also the clarinet family embraces a huge range of notes, normally from around Bb nearly three octaves above middle C on the piano, down to Bb at the bottom of the keyboard, more than three octaves below middle C.
 

The Thameside Clarinet Choir includes the following types of clarinet:
Eb, Bb, Alto, Bass, Alto/Bass Contra.

The Bbs usually have 3 or 4 separate parts.