Posted by Lew on December 23, 2005 at 07:40:37:
In Reply to: Has anybody ever tried to mass load the base cavity posted by Penguin on December 22, 2005 at 20:11:41:
If I am understanding Duke correctly, my experience is contrary to his. First I should note that I
have removed the single "foot" that holds up the M1s under the middle of the panel and replaced
it with two feet, now situated at each end of the arc of the panel. This is immensely more stable
than the standard set-up and by itself had a positive effect on bass definition and "imaging".
Then much more recently I experimented with placing 20-pound dumbells, one on each
backplate. This is where my results may differ from those of Duke. The weights had a
pronounced positive effect on everything, more deep bass with better definition, increased
midrange clarity. When my son asked me to return his dumbells, I went out and bought a pair of
40-pound dumbells for the same purpose. Can't really say that the heavier weight is
significantly better than the lighter one, but maybe a little better. It stands to reason that the
added weights would help (i) to stabilize the speaker on the floor and minimize flexing at the
junction between the panel and the backplate, and (ii) to dampen resonances of the backplate
itself and the cavity underneath. By the way, my speakers sit on a bare hardwood floor; no
spikes are used. I often dream of ways to further stabilize the speaker by running a support
structure from the top of the panel down to the rear of the backplate. So far, I cannot think of a
way to do it that is not too ugly for our living room, given my limited shop skills. I bet it would
help further.