Hi There, finaly i got to buy a gk MB150S for a really cheap price. Sounds amazing with my DB and also with my fretless, very natural sound and loud! But it has a small buzz when i play specially the E string from G down to E. I'm pretty sure it's from the speaker, but it's just like new. I think it could be a tiny hole where the air is scaping and producing this small vibrations. What do you think? What could i do without spending a lot of money? Thanks a lot!