Bookshelf speaker
Encyclopedia
A bookshelf loudspeaker is a compact loudspeaker
, generally sold for consumer-grade home audio applications as part of a shelf stereo
pair or home theater
package, that is compact in size and intended to be placed on a raised surface, i.e. a bookshelf.
speakers. Edgar Villchur, who along with partner Henry Kloss
founded Acoustic Research
, is generally credited with inventing bookshelf speakers. His key innovation was an acoustic suspension
design, by which the woofer
and other drivers were in separately enclosed chambers that could be made stiff and much smaller than the earlier ported designs. Advent, now defunct, was another early manufacturer.
Certain market and technical issues have contributed to the widespread adoption of bookshelf speakers in the 1990s and beyond. Technical improvements and less expensive mass-production technologies have made high-quality bookshelf speakers affordable for most audio enthusiasts. Rapid improvements in amplifiers, digital signal processors and other components has improved the sound quality of low to mid-level home audio systems, which creates a stronger need for adequate speakers. Home theater
systems are increasingly popular, and their multi-channel audio requires five or more speakers rather than the two speakers of earlier stereo
systems. For cost and practical reasons the most common setup is satellite speakers, typically bookshelf speakers for the side, back, and sometimes the front and center channel
s, rather than larger speakers for each channel. Finally, most home theater and many musical home audio applications, began in the late 1990s to incorporate separately-enclosed subwoofer
s to handle deep bass. Human perception of low-frequency sound is relatively non-directional, so a single subwoofer is usually sufficient and may be placed anywhere. This frees up the other speakers to omit the lower end of the frequency spectrum
. Without the relatively heavy, bulky, and expensive low bass drivers
, the speakers can be made smaller.
Loudspeaker
A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
, generally sold for consumer-grade home audio applications as part of a shelf stereo
Shelf stereo
thumb|right|200px|A Magnavox 2.0 shelf stereoThe term shelf stereo refers to any home stereo system that is physically suitable for placement on a shelf or other similar location. Shelf stereo systems are becoming more popular as their capabilities increase while size decreases. The price of shelf...
pair or home theater
Home cinema
Home cinema, also commonly called home theater, are home entertainment set-ups that seek to reproduce a movie theater experience and mood with the help of video and audio equipment in a private home....
package, that is compact in size and intended to be placed on a raised surface, i.e. a bookshelf.
History
At one time, high quality home loudspeakers were exclusively large and floor-standing, whereas small speakers had an exclusive reputation of low price and low audio quality. However, beginning in the 1960s, some manufacturers began making more expensive, compact high fidelityHigh fidelity
High fidelity—or hi-fi—reproduction is a term used by home stereo listeners and home audio enthusiasts to refer to high-quality reproduction of sound or images, to distinguish it from the poorer quality sound produced by inexpensive audio equipment...
speakers. Edgar Villchur, who along with partner Henry Kloss
Henry Kloss
Henry Kloss was a prominent American audio engineer and businessman who helped advance high fidelity loudspeaker and radio receiver technology beginning in the 1950s. Kloss was an undergraduate student in physics at Massachusetts Institute of Technology , but never received a degree...
founded Acoustic Research
Acoustic Research
Acoustic Research was a Cambridge, Massachusetts-based company that manufactured high-end audio equipment. The brand is now owned by Audiovox. Acoustic Research was well known for the AR-3 series of speaker systems, which used the 12-inch acoustic suspension woofer of the AR-1 with newly designed...
, is generally credited with inventing bookshelf speakers. His key innovation was an acoustic suspension
Acoustic suspension
The acoustic suspension woofer is a type of loudspeaker that reduces bass distortion caused by non-linear, stiff mechanical suspensions in conventional loudspeakers...
design, by which the woofer
Woofer
Woofer is the term commonly used for a loudspeaker driver designed to produce low frequency sounds, typically from around 40 hertz up to about a kilohertz or higher. The name is from the onomatopoeic English word for a dog's bark, "woof"...
and other drivers were in separately enclosed chambers that could be made stiff and much smaller than the earlier ported designs. Advent, now defunct, was another early manufacturer.
Certain market and technical issues have contributed to the widespread adoption of bookshelf speakers in the 1990s and beyond. Technical improvements and less expensive mass-production technologies have made high-quality bookshelf speakers affordable for most audio enthusiasts. Rapid improvements in amplifiers, digital signal processors and other components has improved the sound quality of low to mid-level home audio systems, which creates a stronger need for adequate speakers. Home theater
Home cinema
Home cinema, also commonly called home theater, are home entertainment set-ups that seek to reproduce a movie theater experience and mood with the help of video and audio equipment in a private home....
systems are increasingly popular, and their multi-channel audio requires five or more speakers rather than the two speakers of earlier stereo
STEREO
STEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...
systems. For cost and practical reasons the most common setup is satellite speakers, typically bookshelf speakers for the side, back, and sometimes the front and center channel
Center channel
Center channel refers to an audio channel common to many surround sound formats. It is the channel that is mostly, or fully, dedicated to the reproduction of the dialogue of an audiovisual program...
s, rather than larger speakers for each channel. Finally, most home theater and many musical home audio applications, began in the late 1990s to incorporate separately-enclosed subwoofer
Subwoofer
A subwoofer is a woofer, or a complete loudspeaker, which is dedicated to the reproduction of low-pitched audio frequencies known as the "bass". The typical frequency range for a subwoofer is about 20–200 Hz for consumer products, below 100 Hz for professional live sound, and below...
s to handle deep bass. Human perception of low-frequency sound is relatively non-directional, so a single subwoofer is usually sufficient and may be placed anywhere. This frees up the other speakers to omit the lower end of the frequency spectrum
Frequency spectrum
The frequency spectrum of a time-domain signal is a representation of that signal in the frequency domain. The frequency spectrum can be generated via a Fourier transform of the signal, and the resulting values are usually presented as amplitude and phase, both plotted versus frequency.Any signal...
. Without the relatively heavy, bulky, and expensive low bass drivers
Speaker driver
A speaker driver is an individual transducer that converts electrical energy to sound waves, typically as part of a loudspeaker, television, or other electronics device. Sometimes the transducer is itself referred to as a speaker, particularly when a single one is mounted in an enclosure or as...
, the speakers can be made smaller.