Simple active subsonic crossover??

Hi all,

I need a "simple" 24dB/Oct crossover fixed at 20Hz for a ML-TQWT I'm building as part of an active system. I've seen the FMOD inline units and they are what I am after but with a steeper slope. Anyone know how to make one?

http://www.sound.westhost.com/projects.htm

http://ccs.exl.info/calc_cr.html

You would input the speaker impedance and crossover frequency.

Looks like you would want a high pass filter with Capacitors of 2110µF and 4220µF...and coils of 40mH and 180.04mH (assuming they are 4Ω drivers)

Attachment 2326

fo 20 cycles he will have to go active.. that's a bigass cap and a coil like a coffee can.

I have some Hooker Audio ones at the shop. I have no idea what slope they are though.

I guess a better question is... Why? What do you listen to that has a substantial amount of 20Hz and lower content?