When you raise the GROUP MASTER control (which corresponds to the channel INPUT fader or the track for ping-pong recording) higher than the standard level (usually "8" on the fader scale or higher; however, it depends on the equalizer setting), oscillation will occur. (The level meter will peak for the oscillating channel signal.) If you do not correct this situation and you continue to monitor the signal through the headphones or monitor speakers, unexpected oscillation noise will be output, causing damaging your hearing or the headphones or speakers. Be sure to lower the master fader L/R, correct the position of the switches and controls, and redo the operation. 7 DMT-8 Owner's Manual (Chapter 1 Main Features) Chapter 1 r i: ; Main Features of DMT-8 The DMT-8 is equipped with the following functions: