You can adjust the balance and equalizer for audio using the graphic equalizer in the Now Playing control area. The graphic equalizer has an on/off button and several equalizer presets. When you open the graphic equalizer, all the levels will be equal, which is the default setting.
You can switch between the equalizer presets by clicking the Next preset button. You can create a custom setting by adjusting the equalizer to where you like it, and then clicking the Current preset button again to save your settings.
Note To hide the audio settings, on the View menu, point to Now Playing Tools, and then click Show Equalizer and Settings to remove the check mark.