Bit of a strange one but I wanted to open this thread up to allow fellow players to share technique. I have this problem when I try to play a strong forte and above on a besson sovereign Bb Bass I burst notes and have a strong growl, likewise when i play piano and below my tone starts to close up. I use loads of air and try make a point of blowing through the instrument but I dont know how to sort the issue. Any ideas?? I practice regularly and try have the instrument on my face a lot.