If you check the On box and choose one of those presets, your sound output will change according to the frequency adjustments the preset contains. For this reason, the iTunes Equalizer has two dozen presets, including Classical, Jazz, Rock, Bass Booster, Bass Reducer, Treble Booster, and Treble Reducer, and even one called Beats. However, many people don’t know how to apply equalization. It has sliders that let you adjust the volume of each of its 10 bands just drag them up or down. If you’re familiar with the way an equalizer works, you’ll see that the display of the Equalizer window is pretty much the same as a standalone graphic equalizer.
To access the iTunes equalizer, press Command-Option-E, or choose Window > Equalizer. ITunes includes a graphic equalizer that lets you change the volume of ten different frequency bands to alter your music, and, in many cases, improve the sound.
