Launch GarageBand. From the “File” menu select “Import” and browse for the song from which you wish to remove instrumentals. Completely removing a single instrument from a master recording is impossible, a little like removing the egg from a pancake. Using the equalizer tool allows you to hide much of the instrumental.
Click “Track Info” and select “Visual EQ.” This is a frequency-enhancement tool that lets you cut or boost a selected frequency. By cutting the frequencies that are strongest in the instrumental sections -- and boosting others -- you mask the presence of the unwanted instrumental.
Click “Edit.” This opens an equalization curve interface. The curve is superimposed on a grid. The vertical axis of the grid represents amplitude and the horizontal axis represents frequency.
Click “Play.” This enables you to hear your amendments in real-time.
Click on the curve. Move it around the grid. As you move it up, you enhance the corresponding frequency on the horizontal axis. Click on the grid when you hit a spot that minimizes the sound of an unwanted instrumental. This fixes that part of the curve to the selected part of the grid, permanently reducing the presence of the unwanted frequencies. Repeat the process three or four times until the frequency bands most dominant in the unwanted instrumental are completely reduced.
Click “Save” and rename the track.
Launch GarageBand and select your preferred song from the file menu.
Click the “Tracks” tab. This opens an array of separate instrumental tracks and provides access to the song session and its multitrack files, rather than just the master mix.
Click on the unwanted track to highlight it.
Click “Command” and “Delete” to delete the selected instrumental track.