Woofer Speakers

Woofer Speakers

Woofer speakers are specially designed to handle low and low-mid frequencies of the audio specter. They are also known as "bass speakers." Their frequency range is usually set between 40 Hz and 500 Hz. "Woofer" comes from the onomatopoeic English word for a dog's bark, "Woof." At ordinary sound pressure levels (SPL), most humans can hear about 20 Hz.

Low-Frequency Range

Woofers generally cover the lowest octaves of a loudspeaker's frequency range. In two-way loudspeaker systems, the drivers handling the lower frequencies must also cover a substantial part of the midrange, often as high as 2000 to 5000 Hz; such drivers are termed mid-woofers. Since the 1990s, a type of woofer (termed subwoofer) designed for very low frequencies has been commonly used in home theater systems and PA systems to augment the bass response. They usually handle the lowest two or three octaves (from as low as 20 to 80 or 120 Hz). Although all woofer speakers are built similarly, some differences are listed below.

Standard Woofer

A standard woofer produces frequencies from 20 Hz up to 2,000 Hz (2 kilohertz, or 2 kHz). It is often characterized by its bassy sound, which comes from the lower-frequency sine wave. You'll typically see standard woofers as part of higher-end speakers that contain either a woofer and tweeter (a setup known as a 2-way speaker) or a woofer, tweeter, and mid-range speaker (a setup known as a 3-way speaker).

Subwoofer

Subwoofers can only produce tones lower than 200 Hz in consumer systems. They comprise one or more woofers, often mounted inside a wooden enclosure. Although the human ear can only pick up a frequency as low as 12 Hz, subwoofers working at lower frequencies can only be felt if not heard. Subwoofers are the most common add-on to a consumer speaker setup. They are typically placed in their isolated enclosure and provide the low-level thump you can't get with standard woofers.

Midwoofer

Midwoofers fall right in the middle of the 'woofer' range, ranging from 200 Hz to 5 kHz. With such a wide range of frequencies, this speaker will produce the best quality sound from 500 Hz to 2 kHz and start to deteriorate at either end of the spectrum.

Rotary Woofer

A rotary woofer is a woofer-style loudspeaker that uses a coil's motion to change the pitch of a set of fan blades instead of using the cone shape. Since the pitch of the blades is changed by the audio amplifier, the power required is much less than that of a conventional subwoofer. Rotary woofers are also far superior at creating sounds well below 20 Hz, below the average level of human hearing. They can produce frequencies down to 0 Hz by compressing the air in a sealed room.

Source Texts

• What Are Woofers, Mid-Range Speakers, and Tweeters?