825 Cabinet Vibrating

[ngccglp]

Hi,

Much have been written on how to damp the horns. Nut not much on the 825 cabs. One of my 825 cabs, when I played discs with high bass energy e.g. japanese drums, I can hear clearly the buzzing vibration sound of the cabs. All screws are already tightened. I traced the sound to somewhere at the middle rear of the right panel. When I pressed my palm against it, it dampens the buzz.

Is something loose? I opened the cabs but could not find any thing loose/dangling that can be causing the buzz. The only thing that could be causing the buzz, I suspect, is the wooden strip mounted on the inside that is used to take the screws when we mount the rear panel.

Any tips? Thanks.

[Altec19]

If I'm not mistaken the 825 cabinets were always constructed of plywood. Is it possible that what you are hearing is a loose or separated plywood lamination? All of the later cabinets were constructed from MDF board which has no laminations and is more consistent throughout.

[ngccglp]

You're right, the construction is of plywood. But I did not see any plywood opening up.

Do you know if screws are used in the construction or purely by glue only? If its purely by glue only, then maybe some members of the cabinet is beginning to separate. Feel like using screws to tighten the members, but I have not really narrow down to exactly which member is loose.

[Fitts]

Hi,

I had a similar situation with my cabinets and ended up making some braces inside the cabinet. I used 2X2 stock and ran one brace from side to side and another brace from the sloped panel to the top of the cabinet (or bottom if you have the cabinet in the woofer up position).

The side to side one brace is easy to make, just measure and cut for the inside width of the cabinet. The vertical brace has to be custom fitted to match the angles of each cabinet. I made mine so that the brace goes from the center of the sloped panel to the center of the bottom (or top) panel.

After fitting the vertical brace and gluing it in place, I added the side to side brace. It should be put in so that it attaches at about the mid point of the vertical brace. Let it attach to the sides based on where it attaches to the vertical brace.

End result, I can't feel or hear the vibration in the sides of the cabinet any more.

I hope this is helpful,