This circuit is useful for someone with DIY car stereo, portable active speaker or for 2.1 single supply audio amplifier...   Made in Slovakia

Cut-off frequency is set to 160 hz, which is just fine. If you want to tune it, change R10 Value.

 

500 Ohm - 318 Hz cutoff

2k -80 Hz cutoff

 

Use this tool to calculate cutoff:

http://sim.okawa-denshi.jp/en/CRtool.php

 

I used double OpAmp, because they're easier and cheaper to buy here :) 

 

Contact me, to show where you used it please :)