See the bottom of this page for products we sell for treatment and damping of enclosures.

If you are building your own speaker enclosures, or upgrading ones you already have or have bought / are thinking of buying, there are several things to consider.  A major goal of a good speaker enclosure is to absorb all sound coming off the rear of a driver, except that which is deliberately re-radiated, such as by a port or passive radiator.  Also, the panels of the enclosure should not re-radiate energy, and the enclosure (except for a port, if used) should be as well sealed as possible.

Re-radiation is usually minimized by keeping panels stiff and rigid.  This tends to move resonances in the panels higher in frequency than would otherwise be the case, and higher frequency resonances can be more easily “damped” than low frequency resonances.  One can try treating the enclosure panels or constructing them in such a way to be self damping.  An “extreme” example is the old Wharfedale speakers, which literally had a layer of sand between inner and outer panels.  Ie., these were essentially a box within a box, with dead space between the two boxes filled with sand.  (!)  A more common approach is to use damping material, ie., “stuffing” or “filler”, in the enclosure itself.  This material, in higher densities, can have a small effect on panel resonances themselves, but is more valuable in simply helping to absorb acoustic energy in the air space of the enclosure itself, before it gets to the enclosure panels.  It also reduces resonances* that occur in any regular shaped acoustic volume (such as a rectangular box), and it increases the effective volume of whatever space it occupies, slightly.

*A simple test one can try is to speak closely into an empty speaker enclosure, then fill it with about 1 lb. per cu. ft. of fiberfill, a medium effectiveness air-space damping material, and try again.  The difference in lack of “reverb” and “hollowness” in your voice will be huge.

When it comes to making sure an enclosure is well sealed, most people do not realize that commonly used cabinet materials such as particle board and especially MDF are actually pretty porous.  We will post a page discussing this further, soon.  For now, we will simply note that coating all interior surfaces of an enclosure with a good sealer, and caulking all joints with silicone cement or a good silicone enhanced latex caulk (try to find one rated for 35 years or more) is a good idea.  Treat / coat all the interior surfaces first, let dry, and then caulk the corners carefully, leaving no gaps.  Also check to see that no air can leak out of terminal mounting plates or cups, or around the edges of drivers.

Of particular note:  Compressed carpet, such as is often left under the mounting flange of a driver in carpeted enclosures, is an ok gasket from the standpoint of vibration, but it is NOT a particularly good air seal gasket.  If you have a carpeted enclosure, it is better to remove the carpet under the driver flange, and lay in a small strip of Mortite / rope type window caulk, or, even better, automotive strip caulk (available at auto parts stores, some online speaker sellers, etc.)  Another good choice is closed cell foam self-adhesive gasket material, as it is easier / less messy to apply, and does not make driver removal difficult, as strip caulk can.

More info., here.  We will add a discussion of how much enclosure “fill” to use, soon.

Products we sell for treatment and damping of enclosures

      Fiberfill (Enclosure filler / stuffer / damping material)