YA, GREG IS RIGHT..DON'T OVER TIGHTEN THE SPEAKER BOLTS..IT COULD BE TE CASTER WHEELS ON THE BOTTOM ALSO..IF IT SOUNDS LIKE A SPEAKER HAS FAD AWAY BUZZ...CHECK AND SEE IF THE TWO LITTLE SPEAKER WIRES THAT GO TO THE CONE, AREN'T TOUCHING THE CONE ITSELF...IT'S THE WIRES COMING FROM THE TERMINALS ON THE SPEAKER FRAME,....THAT ARE GLUED INTO THE CONE ITSELF....CHECK THOSE OUT....IT DOUBT THE BACK PANEL IS BUZZING, THAT'S A CRUSH FIT . YOU HAVE TO BLAST TO GET THOSE BACK PANELS OFF A SUNN CAB...TO WRAP IT UP....BE NICE TO THE SPEAKERS...BOB....