Stereo graphic equalizers are electronic tone shaping devices used in stereo audio systems for home, mobile, live and recorded music applications. Controlling up to thirty-one frequency bands and properly described by the number of bands controlled -- 31-band stereo graphic equalizer for instance -- they are available as standalone units or integrated into music components.
Frequency Bands and Equalizers
The human ear can detect sound frequencies from a low of 20Hz (Hertz) to a high of 20KHz (Kilohertz). Equalizers employ electronic bandwidth filters to divide this range into smaller groups called "bands." Physical characteristics of different listening environments and audio equipment limitations can accentuate or mask certain frequencies, for which equalizers are used to compensate for and "equalize" or "EQ" sound.
Graphic Equalizer Layout
Graphic equalizers use vertical sliding faders corresponding to specific bands -- arranged low to high, left to right across a horizontal plane -- for which users can manipulate up or down to boost or cut frequencies. Faders in the center position are described as "flat," meaning that no frequency adjustment has taken effect. As faders are adjusted up or down a frequency "curve" is created, with the fader arrangement providing users with a visual or "graphic" aid to the frequency spectrum adjustments.
Dual and Grouped Stereo Graphic Equalizers
Because stereo sound is separated between dedicated left and right audio channels, one or both channels may require equalization to suit the listener. True stereo graphic equalizers are comprised of two sets of slider controls in a common housing -- one for each channel -- and are often called "dual" graphic equalizers. Grouped stereo graphic equalizers employ one set of sliders for both audio channels, and are typically found on lower-end components where the equalizer is integrated into the unit.
Graphic Equalizer Band Configurations
Typical graphic equalizers contain ten to thirty-one frequency-specific sliders, but as few as three can be found on integrated units. 31-band graphic equalizers allow control of smaller slices of the frequency spectrum than their 10- to 15-band counterparts, and are used primarily in high-end audio and recording environments where precise adjustments are necessary. 10- to 15-band equalizers are suited to less critical applications such as home and mobile audio systems where precision frequency control is not required.
Equalizers in the Audio Chain
Because equalizers control frequencies emitting from the sound source, they are connected between the source output and power amp input in modular systems. Sources include radio receivers, CD players, sound mixers, musical instruments and other sound-producing device. Stand-alone equalizers cannot be used with integrated systems that contain the source and amplifier, and are not designed to be placed between the power amplifier and speakers due to high-voltage concerns. Consult your equipment owner's manual for compatibility and proper connection of equalizers.
Tags: graphic equalizers, audio channels, audio systems, frequency spectrum, Graphic Equalizer, home mobile