For may years viola players lived the hype to play on as big violas as possible and makers around the world had to create big ones as 44 and even bigger. Probably better strings and the better making offered musicians also smaller instruments which actually worked very well and in a sudden violinmakers had to create small violas for everyone.
This 39cm viola of mine is a nice example of this very last viola hype where they are switching to as small as possible. You certainly can not compare a small viola with a super large one when it comes to sound volume, but he playability and its sound quality are boosting you into a different world of baby and comfort.
In order to obtain the maximum out of such a small instrument I used a slap cut maple back and I made the body slightly larger to have still a certain body volume. You can hear the great result.