- Open your preferred digital audio workstation, or DAW. Logic and Cubase are two examples. Double-click the desktop icon or launch the program from the "Start," "Programs" menu, if using Windows. If you are using a Mac, either launch with the desktop icon or from the "Applications" folder. The last edited session automatically opens. If this isn't the right session click "File," "Open Recent."
- Click the "S" icon on the guitar channel strip to isolate the audio and mute everything else.
- Open the EQ tool. Different DAWs have different equalization interfaces, each with different names. The main parameters and controls are universal, but the process for opening the equalizer varies according to which program you are using. For example, if using Logic click "Plug Ins" on the guitar channel and select "EQ" from the sub-menu. This opens an equalization interface in a separate dialog box.
- Press play so you can hear your adjustments in real-time.
- Adjust the slider dials for the respective frequency bands. Each equalizer plug-in opens with a preset configuration. This is often a reasonable starting point from which to begin tweaking. Move the slider dials with your cursor to adjust the gain of each particular frequency band. Move it down to cut the gain and lower the prominence of that particular frequency band and up to boost it. If you are equalizing a Fender Telecaster, boost the mid and high frequencies to bring out the guitar's natural "brassy" frequencies. To enhance an the body of an electric guitar's sound, as distinct from the ambiance or resonance, boost the 100KHz frequency range. If equalizing an acoustic guitar that was recorded with a microphone, cut the bass frequencies to remove the natural "boom" that hollow-body guitars have when recorded.
- Click "S" again to unmute the other audio. Click "Bypass" on and off to hear how the guitar sounds in the mix with and without the equalization. Acoustic guitars sit in approximately the same frequency range as cymbals and brass. If there is a mixture of brass and acoustic guitar, the sounds may blend into one another too much. If this happens, cut some of the treble frequencies from the guitar.
- Click "Save" on the EQ dialog box when you reach a sonic result that enhances the guitar's natural sound.
Source : http://www.ehow.com/how_8551008_use-eq-guitar.html