I believe advertised is 27HZ, but it has to go lower. The woofs were replaced with Crites 1526S 15", the mid horns with a Martelli 2" wood Tractix horn with a B&C dcm 50 2" driver and the tweets are B&C DC 10. Al Klappenbergers "Universal Slope" x-overs,-----------------yeah, they're modded, and monsters.