high pass filter

does anyone sell or can i make some sort of high pass filter that goes between an amp and speaker? i am wanting to high pass my bookshelves at 80hz.

rayray802-07-2011 10:16pm

kr4 Details Discussions Posts This discussion Message User 3,649 posts 02-07-2011 at 11:45pm Copy Comment URL Report Comment Edit Delete A capacitor.
kr4 Details Discussions Posts This discussion Message User 3,649 posts 02-08-2011 at 01:52am Copy Comment URL Report Comment Edit Delete 1. You need to know the impedance, not the DC resistance, and you need to know it across the relevant range from about 200Hz down. 2. For 6dB rolloff, only a cap is needed. For 12dB, you will need a cap and a coil. Kal
kr4 Details Discussions Posts This discussion Message User 3,649 posts 02-08-2011 at 02:52am Copy Comment URL Report Comment Edit Delete I really wonder if those numbers will be sufficient. Impedance varies greatly near resonance and is affected by enclosure loading. The rated 'nominal' impedance is estimated at 1Kohms but, in the bass, the difference can be huge. You can measure it best with an impedance bridge or with an AC multimeter. Kal
kr4 Details Discussions Posts This discussion Message User 3,649 posts 02-08-2011 at 02:08pm Copy Comment URL Report Comment Edit Delete Yes, line level would be easier and there are off-the-shelf solutions, as Nmusicman has suggested. BTW, what I meant to say in my earlier post was: Impedance varies greatly near resonance and is affected by enclosure loading. The rated 'nominal' impedance is estimated at 1000Hz but, in the bass, the difference can be huge.