This is how (Alton) explained it to me. Posted 03 December 2013 - 09:13 AM There's a VERY easy way to set the SSF. Start by turning it all the way down and putting in a CD with test tones on it, no music. Start with something like 40hz and turn the volume up enough to get the sub moving. Now switch the tracks down one hertz at a time. As you near tuning you should see the sub moving less and less (while getting a little louder each time) then once you see the sub start moving a little more again you're a hertz or two below tuning. At this point go back and forth on the tracks and figure out which frequency the sub moves the LEAST and that is the tuning frequency of your enclosure. Now put on a track that is 3 to 5 hertz lower than your tuning frequency and turn it up enough to really get the sub moving good but without damaging it obviously. At this point you adjust the SSF up until you see the movement of the sub go down to at least half the amount it was when you started and your SSF is set with no guessing whether it's right or not.