Brent Butterworth

Lots of companies make cars. Lots of companies make video projectors. But when you look under the hood of either product, you’ll realize that not many companies make engines — i.e., the piston engines that power cars and the light engines that power projectors. That still leaves plenty of things to do like add a body, decide which features should accompany the engine, and sometimes tweak the engine to better suit individual needs.

If you're more than 30 years old, you may remember when almost all speakers looked like the BIC RtR 1530 featured in a recent Parts Express e-mailer: big woofers and big enclosures, with little or no effort expended to make everything presentable. Nowadays, in the interest of gaining our domestic partners' permission to buy the damned things in the first place, we demand that our speakers be compact and gorgeous.

Just when you think they're all done adding more channels to sound systems, they add a couple more. The June 18 premiere of Toy Story 3 also marked the premiere of Dolby Surround 7.1, a technology that allows a commercial cinema to add two additional channels of sound to the 5.1 channels they already have. The existing left, center, right, left surround, right surround, and low-frequency effects channels have been augmented with left back surround and right back surround channels.

All audio experts agree that two subwoofers are better than one. With the fervor of a Star Wars nut explaining the Force, they'll tell you how using two subs makes bass response smoother for multiple listeners. But don't worry; it's easy to get the experts to clam up -- just ask them for an easy way to fine-tune the performance of two subs.