Cut the equalizer anywhere from 60 to 200 Hz. Reducing the low-frequency content of the vocal will increase its clarity. Reducing the frequencies at 60 Hz and below will get rid of unwanted low-frequency content. Reducing the frequencies above 60 Hz can help thin out a vocal that is too thick and muddy-sounding.
Boost the equalizer at or around 3 KHz to add clarity to an undefined-sounding vocal. This frequency range is very sensitive to human ears, so a small boost will usually have a significant impact in vocal clarity.
Boost the equalizer at or around 5 KHz to add presence to a dull-sounding vocal.
Boost the equalizer anywhere from 10 to 15 KHz to add air and breath to the vocal sound. This will often give an enhanced and brilliant-sounding top end to the vocal.