So here is a part of the answer
Sound should be self contained so BaseSoundSystem could have
AbstractSoundSystem subclass: #BaseSoundSystem
instanceVariableNames: ''
classVariableNames: 'SoundEnabled SoundQuickStart UseThemeSounds'
poolDictionaries: ''
category: 'Sound-Synthesis'
and class level accessor
Then we can defined adequate method extension in
Sound-Settings that describe the default value
Then SoundService should not have state but delegate to the current install
class player the SoundService supplier.
I hope it makes sense. I will code that.
Stef