Pioneer released it SG-90 graphic equaliser in 1983. It is capable of reducing or augmenting frequency ranges within a music mix or individual audio signal. Graphic equalisers have become essential elements of recording studios and audio production houses.
The SG-90 is designed to manipulate specific regions in the sonic frequency spectrum of an audio signal. The 17-band equaliser divides the sound frequency spectrum into 17 distinct sections. Using the vertical sliders, you can raise or lower the dB level of isolated frequencies.
The SG-90 features two 17-band equalisers, each dedicated to one side -- right and left -- of the stereo field. The SG-90 includes adjustment settings that allow you to calibrate the vertical sliders to a 6 or 12 dB adjustment range. The equaliser also includes auto-fade functions that can merge slowly merge sounds from alternate playback sources.
You connect audio input sources, such as record players or stereos, to the SG-90 using stereo cables. Sounds played through these devices will be input into the equaliser before being output by your speakers. You can use the SG-90s 17-band equaliser to modulate received sounds. Reduce or exaggerate bass levels by lowering the vertical sliders on the left side of each equaliser unit. Raise or lower treble levels with the vertical sliders on the right side of the equaliser.