The aim of this study is to evaluate different damping material of a box of 15 L with a KEF B200 driver.

Materials tested

1.  Fine BAF salvaged from loudspeakers over the years. Tested at 0, 100, 200, 300 & 400 g giving a packing density from 6.7 to 27g/l =(kg/m3). Firmly packed at highest density. Evenly distributed at all tests.

2. Pharmacy type cotton.Tested at 0, 100, 200, 300 & 400 g giving a packing density from 6.7 to 27g/l =(kg/m3), some space left at highest density. Evenly distributed at all tests.

3.  Coarser BAF sheets for bass reflex boxes 83 gram each (Biltema) tested at  0, 83, 166, 249  and 332g (the 5th mat in the pack did not fit) Uneven distribution with the sheets against the back wall and then piling forward

4. Open foam one sheet 50 mm thick covering the back of the box was 100 g and only one of them fitted.

To to conclude different types of BAF and Cotton and at least the foam I tested does seem to give similar results in lowering the Fr and reducing the Qms that is increase resistive losses.

Next time around, if there will be one!

Having  the driver the other way around so that the magnet structure does not interfere with packing the box. Perhaps also test the african sheep wool that I have.