Many of Earthquake's subwoofers are equipped with a SUB-LFE switch button. This button allows the optimization of the subwoofer depending on the input signal.

When the button is in the LFE position expect the subwoofer to receive a pre-filtered LFE signal from the processor / receiver / decoder. This means the signal will only contain the bass information you wish reproduced by the subwoofer without any high-frequency information.  Choosing the LFE setting disables the  built-in subwoofer crossover and the subwoofer can play up to 2 kHz. The advantage of this is that the signal only has to go through a crossover which will maintain optimum sound quality. It also allows perfect integration with special filters and advanced DSP devices.

When the button is in the SUB position, the subwoofer's built-in crossover is cut and divides the signal. This sharing can be adjusted through the frequency button, which changes the frequency the subs share. This setting is used when subs receive a full-frequency signal or sub-signal that you want shared deeper than one processor could.

See illustration.