Mounties Feedback Trainer was designed to help you learn to correctly identify feedback tone frequencies - an essential skill for any budding sound engineer, as well as useful for any musician.
You can use it to train your ear to detect the various frequencies and then test yourself to see how well you know which frequency is which - far better to learn it now than when you have to quickly silence a wayward feedback in a crowded theatre!
Mounties Feedback Trainer includes a built in equalizer so you can adjust the volume of the tones for the wildly variable output of your particular speakers.