Select > Stereo Settings > Audio Zones, and if necessary, select a zone.

Zone Name

Sets the name of the zone.

Loud

Boosts the high and low frequencies.

Subwoofer Filter

Sets the low-pass frequency of the subwoofer.

Bass

Sets the relative volume of low-frequency audio.

Middle

Sets the relative volume of middle-frequency audio.

Treble

Sets the relative volume of high-frequency audio.