I am building a system with an LE14A woofer in a ~4cf cabinet and an LE85 driving a 500Hz Tractrix horn. For the initial try at an XO, I copiesd the L200B which has a second order roll-off for the woofer and a third order for the LE85 plus a high freq boost. I tested the upper section separately and found it did, indeed, roll-off at about 18dB/oct below 1000 Hz, but there was a broad peak centered at ~7000. I tamed that with a series LRC filter (6uF, 0.1mH, 30ohm) and got a nice flat response. The problem is that when I hook up the bass section, all of a sudden the nice 18dB roll-off of the horn goes crazy and it still has significant output (down only 5-6 dB to 100 Hz! I tried running the woofer full range (no network) and the same thing happens. I am getting feed-through from the woofer into the horn somehow screwing up the response!
HELP!!!