21Symptom Likely Cause What to doNoise or hiss heard at outputsNoisy source device Disconnect the devices that are connected to your mixer one at atime. If the noise goes away, the problem is withthe source or the connecting cable.Unused channel volumesare up too high Lower the channel volume on unused channels to “0”Feedback Microphones are too closeto the speakers Speakers should be between the audience and the microphones inorder to avoid feedback.Headphone signal is weakMONITOR OUTPUTis turned down Turn up the "monitor output volume" on the mixerChannel Input is too low Make sure that the channel input volume is turned upImpedance mismatch Your headphones have too high of an impedance.Try a different set of headphones.