Project #2 - Sub-Woofer Crossover

Since I built a speaker cabinet for my second project in the Extreme Freestyle Hacking class (ref: EFH Project 2), I thought a more traditional use of the cabinet as a sub-woofer would be appropriate. A crossover for sub-woofer frequencies would make progress toward my dream of a 5.1 surround sound system.

This crossover is experimental in that it has a single- channel input, mixing a stereo input to monaural with high- and low-pass outputs with a center frequency of 150Hz. Its slope is 18db per octave. My thought being that (especially since it is built on perfboard) my first attempt at such a device might take a bit of component-value tweaking to get both outputs to sum without a dip or peak at the crossover point. Once those values are confirmed or adjusted, I can build a five-channel device, more practically on a custom printed circuit board.

The presentation consisted of a demonstration of the sub-woofer with several short cuts of music, classical and contemporary, all of which contained frequencies below the 150Hz crossover point,

including the last minute and a half of the Telarc recording of the 1812 Overture. The final cut was a replay of the F16 take-off from the Austin Bergstrom International Airport recorded for the EFH demonstration. My demo system consisted of a CD player, a QSC amplifier, a 2-way Frazier commercial speaker system for high-pass frequencies, and the sub-woofer.

Frankly, I was disappointed with the initial trial of the crossover in a large room. I definitely needed more time to adjust the high and low frequency balance.