6.2Signal LED, Clip LED, and VU Meter
To the right of the Channel Level control are the Signal and Clip LEDs and the VU meter.
The green Signal LED automatically illuminates when a signal is being received. The red Clip LED automatically illuminates when the signal is clipping., or attempting to deliver an output voltage or current beyond its maximum capability. Clipping will distort the sound and can damage a speaker.
The VU meter not only illuminates green, yellow, or red (depending on the signal level) but also has a scale ranging from -60 to 0 to help you indicate the actual signal level.
See also: