Equalizers are audio processing tools that you can use to alter the tone of an instrument or voice. Proper vocal equalization in a live setting can add power, increase intelligibility and remove unwanted noise from the vocal signal. Without knowing too much about equalization, there are a few basic guidelines you can follow to improve the sound of live vocals using EQ. With a few quick adjustments on an equalizer, you should be able to improve the sound of any vocal.
Roll off or decrease the low frequencies below 80 Hz on your vocal equalizer to remove unwanted rumble. Rolling off these frequencies will eliminate all low frequencies below the frequency selected whereas simply decreasing the low frequencies will de-emphasize, but not completely eliminate them. If low frequencies are not present in the particular vocalist’s voice, such as with a female vocalist, low frequencies can sometimes be rolled off all the way up to 250 Hz. By doing so, you will help increase the clarity of the vocals by reducing the low frequency content coming from the stage.
Decrease the frequencies between 100 to 250 Hz on your vocal equalizer if the vocal sounds boomy (as if the vocalist were singing into a box). Reducing this frequency range will minimize this effect and improve the clarity of the vocal.
Boost between 350 Hz and 2000 Hz on your vocal equalizer to add power to the vocals.
Boost the vocal equalizer between 1.25 KHz and 4 KHz or 4 KHz and 8 KHz to improve vocal intelligibility and clarity. Be careful not to boost too much in these ranges, as doing so can cause sibilance in the vocals. Sibilance, which is comprised by "ess" sounds, can become harsh and overwhelming if the highs are boosted too much.
Roll off or decrease the high frequencies above 8 Hz to remove cymbal bleed if a drum set is on stage with the vocalist.