Bass and Treble Controls

For Buick these are separate rotary control knobs. On Oldsmobile this control is a 270 degree rotary pop-out/pull knob with the center detent that is shared between BASS and TREB (treble). This control is used for adjusting the system's audio frequency response. The BASS function is operated by first depressing and releasing the knob to the "out" position. This affects only the lower audio frequencies and has a center frequency of 60 Hz. The TREB function is operated by first depressing and releasing the knob to the "out" position, then pulling to the fully "extended" position. This affects the high audio frequencies and has a center frequency of 10 kHz. Center position of a given control indicates "flat" response over that particular frequency range. Moving a control to the right of center position produces boost, while moving a control to the left produces a cut in frequency range related to that control. All units incorporate a loudness feature that automatically increases bass bias at low listening levels. On Auto Tone Control (ATC) models, any adjustment of these controls will activate the "MANUAL" tone control (ATC) mode and will establish the "MANUAL" ATC mode as default. The "MANUAL" tone mode will be displayed on the "ATC" models while the radio display is not affected by Bass and Treble changes on non-"ATC" models.