What is the purpose of rumble filter?
Only PEQ and XLR models have a rumble filter, so the following discussion only applies to those two models. The rumble filter is a 3rd order high pass filter with corner frequency at 20 Hz to provide a steep roll-off below 20 Hz. It is useful when playing LP records, or when there is unwanted subsonic signals in both movies and music that makes the cone move in and out wildly without making audible audible sound. When it is on, it changes the roll-off of sealed subwoofers from 2nd order to 5th order, and vented subwoofers from 4th to 7th order. Those who are more familiar with filter design will be interested to know that our extension filter is a 2nd order filter to set up the roll-off frequency for both sealed and vented subwoofers. With the difference of order between rumble filter and extension filter, one can actually get more flexible roll-off slope. For instance, in the following we list 3 possible roll-off slopes. Configuration 1: a sealed box with rumble filter off and extensi
