By Wilde Becker. Speaker Stands. At Sunday, July 21st 2019, 19:22:31 PM.
If you already have a pair of simple foam speaker platforms, you can improve their performance simply by gluing a heavy floor tile to the top. Ordinary contact adhesive works fine for this. Then you can either glue some kitchen mat to the upper surface, to provide some grip, or use Blu–Tack, as discussed earlier, between the tile and the loudspeaker.
Thus, the sand provides dampening, but it also prevents the stand from ringing when it’s excited by the right frequencies – another handy little add-on.
That’s where you need to put the sub. If your sub has a phase adjustment knob, or a polarity–invert switch, adjust this until you hear the loudest result from frequencies around the crossover point, typically 80 to 120 Hz.