This is definitely an area prone for feedback since the signals are being amplified then pointed directly at the performers head and that signal is the same as the singers’ voice which is entering the microphone. Feedback 
city! There are ways around this but they don’t always help you to identify the problem frequencies with the exception of a few EQ units. One graphic EQ that offer help in this area is the ART HQ231 Dual 31 Band Graphic Equalizer with Feedback Finder, the name says it all! The EQ is much like many other dual 31 band graphic equalizers on the market however this one has the must-have feedback finder. The way it works is during operation, various EQ band LEDs will illuminate as the HQ-231 processes a signal. The loudest band will correspond with the brightest LED. When feedback occurs, FDC (and its brightest LED) shows you exactly where to adjust – it’s that simple! You’ll also know you have properly set the signal as the LED reduces its illumination. This is definitely one of the most useful and affordable graphic EQ solutions around.
-Ryan
Tags: ART-HQ231, Feedback-Finder, Stage-Monitor-EQ
