The Peavey Mark VI, manufactured by Peavey, is a bass head that puts out 250 watts at 4 ohms and 400 watts at 2 ohms. Besides its built-in compression and chorus, the Mark VI has built-in active crossover with a variable crossover frequency point, which allows bi-amping -- splitting the signal between high and low frequencies. If you're interested in bi-amping, the Mark VI makes it easy -- simply set the frequency where you'd like the signal to be split, plug in a cab for each frequency, and you're off and running.
Set up and plug in your Peavey Mark VI. Don't turn it on just yet.
Set up your bass cabinets. Choose one bass cabinet for lows -- say, one with a 15- or 18-inch speaker -- and another for highs, perhaps with 10-inch speakers.
Notice the "Electronic Crossover" knob on the back of the Mark VI. Choose the frequency. Start by turning the knob all the way clockwise, and you'll be in the kHz territory -- the high sounds. As you move toward the left, counterclockwise, you gradually move into the lower frequencies, until you get to 2Hz. Be aware that choosing a crossover frequency that's too low may cause damage to the high-frequency drivers.
Use speaker cables to connect your cabinet for lows to the quarter-inch "Low Out" output. Use another cable to connect the speaker you've chosen for high frequencies to the quarter-inch "High Out."
Power on your Mark VI. Start with the "Electronic Crossover" knob toward the right. Play and listen.
If you are unhappy with the sound, turn off your Mark VI before making adjustments.