where is the monitor exactly in relation to the singer?

if its behind them...there is your problem. The monitor needs to be in the dead spot of the microphones pick up area. this is normally on the floor facing the back of the microphone.

next (and before your audience arrives) increase the volume of your monitor until you start to get feedback. (is the feedback high, mid or low frequency?) adjust the eq that matches the frequency of the feedack (probably in the mid area) on the mixer until the feedback reduces. increase the volume again and once again adjust the eq until you reach the best mix of volume and tone.

You will struggle a little as the CM30 only has 'low' and 'high' adjustments, but it might help. placement of the speaker is most important though.

TWD

[This message has been edited by Tonewheeldude (edited 03-23-2010).]