OTHER TECH

SPEAKER TYPES

DIRECT-RADIATING Any speaker that's not a dipole, bipole, or Omnipolar. Until dipole surround speakers came along, almost all speakers were direct-radiating. BIPOLAR A speaker that radiates sound equally and in phase in opposite directions. DIPOLAR A speaker that radiates sound equally in opposite directions but with opposite phase or polarity (see bipolar). Dipolar speakers are sometimes used for the surround channels in home theater systems because they create a diffuse sound field in that application. OMNIPOLAR A speaker that radiates sound equally in all directions, a.k.a. omnidirectional. ("Omnipolar" is a trademark of Mirage Speakers.) ELECTROSTATIC A speaker with a large plastic-film diaphragm that, when excited by the electrical output from an amplifier, moves back and forth between positively and negatively charged perforated-metal panels to produce sound. HYBRID ELECTROSTATIC Since small electrostatic speakers can have trouble producing bass, hybrid models have a cone woofer at the bottom of the cabinet to handle the lowest frequencies. PLANAR-MAGNETIC These speakers have a metallic ribbon or a long looping wire embedded in a plastic-film diaphragm that vibrates between arrays of permanent magnets when excited by an amplifier's electrical output.

Sales guys in high-end A/V shops often get a bad rap - sometimes deservedly so. In my own experiences in New York City, I've encountered two kinds I'd prefer to avoid. The first is the hard-sell type, who starts by asking if you plan to buy any equipment today or unwaveringly steers you toward a specific brand of gear. The second is the passive seller. Instead of asking exactly what you're looking for, he flips in a CD and lounges back on the listening-room couch, smiling, hoping you'll interpret his bliss as an indication that the speakers sound awesome. If you encounter either of these guys, beat a hasty retreat and don't look back.

You want a salesman who listens carefully to your needs, then offers specific product recommendations that address them. Once again, I'd steer you toward specialty A/V stores. Bad salesman-types aside, you're more likely to find honest, informed help there - people who have actually been bitten by the home theater or audiophile bug, as opposed to someone who transferred from the PC peripherals department last week.

Auditioning Speakers We've already established that the best place for auditioning speakers is a quiet, dedicated listening room with an attentive, informed salesman at your side. But what else should you look for? You'll probably want to compare several brands, and possibly speakers that use different technical approaches to creating sound. Direct-radiating types are the most common, but you might find that you prefer the sound of bipolar, dipolar, or Omnipolar (omnidirectional) models. Also, while almost all speakers still use tried-and-true cone or dome drivers, you might want to listen to some more unusual technologies, such as flat-panel electrostatic or planar-magnetic models. (See "Speaker Types," above.)

So you can hear a variety of speaker brands and types and compare their performance, any room you audition in should have a switcher. This is basically a set of buttons that either you or the salesman can press to perform on-the-fly A/B comparisons of the same music. The switching setups in stores are rarely ideal - for a truly accurate comparison, the speakers need to be level-matched, since a louder-sounding speaker will often sound better just because of that - but for comparison purposes, imperfect switching is better than none at all.