Apple AppleVision monitors (OS 7.1) - Manual (Page 21)

2 Adjust the volume of the computer speaker by moving the Computer Speaker Volume
slider.
Note: On some computers, the sliders shown may have different names, but
they will still adjust the internal speaker settings.
3 Adjust the Computer Speaker Balance slider, if available.
If your computer doesn’t support balance adjustment, the slider won’t appear
in your control panel.
Adjusting computer sound output volume
To adjust the volume of the computer’s sound output port (marked by an
-),
follow these steps:
1 Open the Monitors & Sound control panel, then click the Sound button.
2 Adjust the balance of the sound by moving the Sound Out Balance slider, if available.
3 Adjust the volume by moving the Sound Out Level slider.
Note: The sound output adjustments change the sound sent to the computer’s
headphone jack. If you have RCA-style sound output ports, such as on the
Power Macintosh 7600 and 8500, those ports are permanently set to “line
level out” with centered balance and are not affected by these controls.
21 Sound Settings
Adjust these
settings.