Acoustical Speaker Cabinet Stuffing

For people who like to make DIY projects out of everything, building your own speakers is one of the more advanced levels of “do-it-yourselfdom.” There are plenty of strategies and techniques to use, to the point it may get confusing what can actually work. But one way a person can get the most out of their setups is with speaker cabinet lining, typically using polyester batting.

Speakers are housed in boxes to block bouncing sound produced by rearward sound waves. Those bouncing waves can still muddle sound however. The addition of fiberfill upholstery batting breaks up the waves and air movement, making the speaker function as if it were in a bigger box, performing better and generating deeper, crisper bass. Often used for stuffing pillows or cushions, the fibrous material is excellent for filling speakers because the fine strands provide enough resistance to improve sound, without blocking the movement of air within the box. Batting can be easily pulled apart by hand for the loosest filling or left alone to line the sides of the box for a tidier design.

The rule of thumb is to add one pound of fiberfill for every cubic foot of airspace a box possesses, but trial and error to discover what sounds best to your ears is the only way to guarantee the sound you want. Some individuals use fiberglass but the movement of air generated from the speaker can blow fiberglass shards out of ports and vents. Polyester fiberfill is nontoxic and will not break down over time, making it a great material to improve the sound in your speakers.