Hold the Option (or Alt) key and drag across iZotope Ozone''s EQ graph to audition just one frequency band.

One of the secrets of using EQ is that cutting the problem frequencies is often more effective than boosting the good ones. Cutting creates more sonic space, allowing parts to blend better. A quick technique to find the problem frequencies is to boost a narrow frequency band with a parametric EQ as you sweep the frequency range up and down. When you hit a problem area, it will really stand out. You then reduce the level at that point.

iZotope Ozone, the powerful mastering plug-in, has a clever hidden feature that makes that search-and-destroy mission easier. If you hold down the Option key (Alt key on Windows) while dragging across the paragraphic EQ, Ozone will temporarily set all other EQ bands to zero so you can sweep without affecting your curve.