What do low pass/high pass filters on an amplifier do for a subwoofer?

High pass is for use with smaller speakers (6.5" and smaller) that aren't capable of reproducing low (subwoofer) frequencies. These front stage/full range speakers typically run out of steam when they get much below 100hz.

Low pass is for subs. Depending on the particular sub and the enclosure it's in generally low pass is set to about 80hz but it can range from around 60 to 100. Most subwoofers start to sound sloppy when they try to play higher frequencies, and at that point the front stage speakers should produce almost all the sound.

Some amps also have a subsonic or infrasonic filter for subwoofers. It is a high pass filter, but it is set to a very low frequency, usually 15-30hz. It is to protect the sub from ultra-low frequencies that COULD cause mechanical damage in a high tuned ported enclosure, and/or with music containing unusually low frequency material.

Subwoofer High Pass Filter

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RE:

What do low pass/high pass filters on an amplifier do for a subwoofer?

Just wondering- I just got a sub and am still playing with the amp settings- thanks.

lol,,, running out of steam when it hits 100 hertz = bad sound quliaty,,,, bass up front = good sq,,,, midbasses make all the differnce in the world when in it comes to front stage sound quality,,, the guy above me is right,,,,, true audiophiles like me , our front stage ( focal k2p) can play down to 70 hertz easily ,, soon i will be able to turn it down to 50 hertz when i add some cdt audio midbasses!!!! cant wait!!!!! its gonna sound like a movie theater in thier!!!!!!!!!!!!!!!!!!!!!!!!1