There are few methods for dampening the walls of
loudspeaker enclosures. All of these methods of adding mass to the cabinet
wall are viable. However, I believe with proper box construction they are
unnecessary. I have not used an accelerometer to test this. I have
only done some comparative testing using my wife's ears.
One method suggested in Vance's book is loading roofing cement
with sand in a 50/50 ratio and placing a layer on the interior of cabinet
walls. I did this to one of the walls in my cabinets. Not only did
it smell profusely for many weeks, it still smelled slightly after about 1
year. If I put my nose up to the porthole on a warm day, that stuff still
smells! If you are going insist on using roofing cement and sand to fix a
resonant cabinet, use the latex variety. It smells less.
I compared the sand/roofing cement treated cabinet with a
non-treated cabinet, and found no audible difference.
This is likely because the largest spread I have
between the vertical braces connecting the top and side walls in my cabinets is
about 3 1/2". This means that there is some support structure every
3 1/2". The side walls are built from 3/4" MDF, and the vertical
braces are also 3/4" + MDF. My cabinets do very well with the "rap
test". They feel very solid, and produces very tight bass.
With my cabinets, dampening cabinet vibrations is overkill, and it smells.
Some folks disagree with me on the issue of
dampening materials to the inside of a cabinet. Dennis Murphy did a test
with Black Hole 5, and did find a slight increase in clarity in the lower bass
region. But this was in a cabinet that was relatively un-braced.
There were nice large open panels with no support. This translates to
panels that are weak/floppy and create that nice "warm" bass sound.
Dennis remarked that the Black Hole 5 effectively dampened some of the cabinet
vibrations, and cleaned up the sound. I would rather spend the $5 on some
good braces during the construction process than @$100 on Black Hole 5 without
I am not saying that Black Hole 5 has no other
purpose, but IMO your $100 would be wiser spent elsewhere - like on some Goertz
Again, if you do insist on using the roofing
cement/sand brew - get the latex based variety. You will pay slightly more
for this, but it doesn't smell.