How can I drive a pair of speakers and a subwoofer with a single car audio amplifier?

One of the keys to getting the most out of your audio investment is choosing gear that will go to work for you now, and won't become obsolete as your system grows. Most car audio amplifiers boast a design flexible enough to keep them in the game as your set-up expands. If you go with a 4-channel amplifier, powering a pair of front speakers and a subwoofer is a breeze. You'll simply want to run your amp in what we call "true" 3-channel mode. To do this, bridge the rear channels to power your subwoofer, while the front channels drive the pair of regular stereo speakers. Bridging the rear channels means combining them in mono mode to create a single channel. Choose an amp that lets you engage a built-in, low-pass filter on this bridged channel. The crossover, along with the increased output from the mono channel, makes this an ideal way to power your sub. As your system grows, you may dedicate a separate amplifier to your sub. At that time, you could add another pair of stereo speakers ...  more