Firstly, ensure you have a 'clean' signal from your PA mixer by making sure the monitor output level control is not set too high. Use the main/lead vocal mic to set the foldback level with all other mics turned down or off.

 

Increase the mic level control on the monitor mixer (or powered monitor unit) towards the desired level, checking for unwanted overtones by speaking into the mic. The sound should be clean and tight - adjust bass and mid-range controls to remove any annoying booming bass or mid-range overtones.

 

Continue to increase the level - adjust treble and notch filter controls to defeat any feedback which may occur. When the sound is clear, defined and loud enough you can fade in the other microphones, one at a time following the above procedure.

 

Remember that different makes and styles of microphones will react differently so don't be surprised when the controls end up in differing positions for each mic.

 

The 3-band EQ and filter facilities provided on Torque powered monitors are particularly useful as they allow you to select the frequency at which feedback is occuring and cut the level of that frequency to defeat the feedback with only minimal effect to the overall sound.