10 Things About Sound That You Were Afraid to Ask

Frequency, Dispersion, Woofers... don't let these words scare you - they all sound great.

1. Tweeters are the smallest speaker drivers, providing high sounds. They are often 1 inch or so in diameter and shaped like domes.

2. Woofers are the big drivers in a speaker that provide the low bass sounds. They are often 8 or 10 inches or more in diameter.

3. Midrange drivers provide the sounds in the middle of the audio spectrum. Having midrange sounds is important, because most people are more sensitive to sounds in this range than they are to highs and lows.

4. Subwoofers provide low sounds for movie effects like explosions and for music with deep bass. They usually consist of one of more large woofers. An active subwoofer contains its own amplifier, while a passive subwoofer does not.

5. Powered speakers are active speakers, meaning they have built-in amplifiers.

6. Ohms are units of electrical resistance, or impedance, but all you need to know is that you should match the resistance of your speakers to that of your receiver or amplifier (whichever connects to your speakers). Typical impedances are 4, 6 and 8 ohms.

7. Frequency range refers to the audio frequencies, or sounds, a speaker will play, anywhere from about 20 Hertz (low bass sounds) to 20 kilohertz (high sounds).

8. Decibels (dB), is a measurement of the intensity of sound, not necessarily its loudness. A typical movie’s dialogue is at about 85 dB, and its loud action scenes are at about 105 dB.

9. Sensitivity rates a loudspeaker’s responsiveness. It is measured in decibels, usually from about 86 to 93 dB—the higher, the better.

10. Dispersion refers to how sound spreads out, typically from a loudspeaker. In a home theater, the surround speakers on the sides or in the back of a room should be very dispersive, spreading ambient sounds, like crickets in the night, throughout the room.