I was just wondering why most beginner clarinets are in Bb? Why flat? Were the early clarinets in such keys as Bb, Ab and Eb? I know some are in A and C but they seem the exception.
GREAT question! There were/are the octave clarinets that were tuned to C and Ab. The Ab is tuned to a minor 7th above the Bb. There were the piccolo Eb and D clarinets that belong/belonged to the piccolo clarinet family.
But the story of the clarinet's evolution is a dark one, full of mutants and variations and absolutely weird brothers, sisters. and odd uncles.
The clarinet is a descendent of a Baroque era instrument
, a single-reed cylindrical bored instrument that had very few keys. It is believed to go back in history as far as the 1200’s. The family included a funky-looking bass chalameau whose bell pointed upward. The mouthpiece was affixed to the body via something akin to a saxophone neck or a bassoon bocal.
There was also a tenor, an alto, and a soprano chalameau, each keyed differently because they were different sizes. (Why each was built to particular dimensions is anyone’s guess, but it could have been to achieve accurate intonation relative to other instruments).
Then someone got a bright idea to add a register key and extra keys and tone holes and pads to cover them. Then the chalameau as it was known disappeared from common usage by 1800 because the instrument with more keys and holes replaced it. This was the clarinet. It could do what the chalameau could do and more.
The soprano clarinet as we know it today exists in the key of A as well as Bb and Eb, but the transition wasn’t without weird twists and turns. Someone named Schuller created a clarinet that --- wait for it--- played quartertones and employed two parallel bores!
But to address the original question: why is the modern soprano (and presumably the "beginner) clarinet tuned to Bb?
I don't know. Just be glad that it wasn’t tuned to Db!