Graphic equalizers are the most common type of equalizer for home audio equipment. A graphic equalizer's controls usually consist of a series of vertical sliders; each slider raises or lowers the volume of a specific frequency range. A parametric equalizer, on the other hand, allows you to specify the ranges of frequencies that each control affects; this flexibility makes it well-suited for audio production and recording. Shelving equalizers are the simplest type: they raise or lower the volume of the sound above or below a specified frequency.
Use the equalizer on your stereo system or in your computer's music player program to optimize music for the listening environment. If you're listening to rock or pop music, raise the middle frequencies to bring out the voice and guitar; boost the low frequencies to make the bassline thump. If the recording to which you're listening contains tape hiss or other high-frequency interference, lower the highest frequencies slightly. Nearly every software equalizer -- and many hardware equalizers -- include preset equalization settings for different genres of music; try out these presets, then adjust the controls as necessary.
Equalization is one of the most important parts of producing, recording and mixing music. If two elements of a song share the same frequency range, they will conflict with each other. Use an equalizer to shape the sound and remove this conflict. A kick drum, for example, usually peaks around 60 hertz. A synth bassline usually ranges from 30 to 200 hertz; this means that the two sounds conflict at 60 hertz. Use a parametric equalizer to lower the volume of the bass at 60 hertz, thereby reducing this conflict.
Use the three-band equalizers on your DJ mixer creatively to add impact to your DJ sets. For example, you could reduce the bass on the song that's playing, then lower everything but the bass on the track that you've cued up to play next. Start playing the cued-up track, then slowly sweep the crossfader to the middle. The bassline on the second track combines with the mid-range and treble-elements on the first track to create a new song. With practice, you'll be able to smoothly mix different elements of tracks together using the mixer's equalizers.