Samson MPL 1204 Owner's Manual page 7

Guided Tour - Channels
7: Level (white) - This knob (purposely made a little bigger than the others so
you can find it easily in low-light situations) controls the volume of the channel
input. In practice, you will use the Level controls to continuously adjust the
loudnesses of the various signals being blended together by the MPL 1204.
The "0" (2 o'clock) position of the knob indicates unity gain (no level attenuation
or boost). Moving the knob counterclockwise from the "0" position (towards " ")
causes the signal to be attenuated (at the very bottom, it is attenuated infinitely—
in other words, there is no sound). Moving it clockwise from the "0" position
(towards "+10") causes the signal to be boosted by as much as 10 dB.
For best signal-to-noise ratio, all Level controls for channels carrying signal
should generally be kept at or near the "0" position. Channels that are unused
should have their Level controls kept fully counterclockwise at their " "
(minimum) level. See the "Setting the Correct Gain Structure" section on
page 14 in this manual for more information.
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