LOB: Larger Open Baffle
The preferred crossover system is the First Watt B4 electronic crossover. This will be available in early 2010. As shown at RMAF, a bass boost centered at 30 hz was used to keep response flat. At this time, it is not known if production versions of the B4 will be able to provide this.
If you want to use a passive crossover, here are the crossover values:
8 Ohm: Woofer: 22.5 mH in series, 176 uF parallel
8 Ohm: Lowther: 94 uF in series, 12 mH in parallel
16 Ohm: Woofer: 45 mH in series, 88 uF parallel
15 Ohm Lowther: 47 uF in series, 24 mH in parallel
Those of you astute with crossovers recognize that something appears amiss here. Both crossovers are 2nd order (12 dB/octave), and should be wired in phase (the - of the amp to the - of the driver, the + of the amp through the crossover to the + of the driver). The crossover point for the Lowther is 150 Hz, for the woofer it is 80 Hz. However, the baffle size acts as a 3rd pole in the network, and allows filling in between the crossover points. For more information about this, see Martin Kings TQWT site.
I used solid cherry for the panels. The Lowther is front mounted, slightly recessed into the panel. The 416 was rear mounted, with a 13-1/4 inch hole in the front with a 3/4 radius curve. A 13-1/2" diameter mounting hole in the rear kept the woofer from being all the way at the rear of the panel. This is all visual, and not important to the sound. Please modify these to fit your own taste.
Link to Plans
8 Ohm: Lowther: 94 uF in series, 12 mH in parallel
16 Ohm: Woofer: 45 mH in series, 88 uF parallel
15 Ohm Lowther: 47 uF in series, 24 mH in parallel
Those of you astute with crossovers recognize that something appears amiss here. Both crossovers are 2nd order (12 dB/octave), and should be wired in phase (the - of the amp to the - of the driver, the + of the amp through the crossover to the + of the driver). The crossover point for the Lowther is 150 Hz, for the woofer it is 80 Hz. However, the baffle size acts as a 3rd pole in the network, and allows filling in between the crossover points. For more information about this, see Martin Kings TQWT site.
I used solid cherry for the panels. The Lowther is front mounted, slightly recessed into the panel. The 416 was rear mounted, with a 13-1/4 inch hole in the front with a 3/4 radius curve. A 13-1/2" diameter mounting hole in the rear kept the woofer from being all the way at the rear of the panel. This is all visual, and not important to the sound. Please modify these to fit your own taste.
Link to Plans