GoldWave is a shareware audio application that lets you record and edit audio. With GoldWave you can remove or partially remove the vocals from an audio file. This is useful if you want an instrumental-only version of a song, to use as a karaoke backing track for example. GoldWave does this by permitting you to mute certain frequencies in the audio. By zoning in on the vocal frequencies and muting them, you can effectively remove them from the audio. The degree of success you can achieve depends on the quality of the audio and the frequency range of the vocal therein.
Click "File" and select "Import." From the browser, select the audio file of the song from which you wish to remove the vocals. This opens the audio as a wave form graphic, with peaks representing various volume levels. The taller the peak the taller the volume.
Highlight the portion of the song you wish to remove the vocals from. Click on the wave form graphic and drag the cursor along. Release it when you reach the end of the desired selection. To remove vocals from the entire song, don't select anything. This configures GoldWave to remove vocal from all of the audio file.
Click "Effect," "Stereo" and select "Reduce Vocals" option. This opens a new window containing a presets menu. These presets are configured for removing vocals of differing frequencies. You can set your own frequency parameters but first work through the presets. For example, select "Reduce Vocals with More Stereo." This means that vocals mixed in stereo will be removed. Since most recordings have stereo vocals, this should work with most recordings.
Click "Preview." This enables you to hear what the GoldWave "Reduce Vocals" tool is doing, in real time. This is useful because you don't need to fully process the audio to then find out the effect hasn't worked as expected.
Manually select the frequency threshold. If the automated process hasn't fully removed all vocals, use the horizontal slider dials marked "From (Hz)" and "To (Hz)" to select the frequency parameters. Any audio between the selected frequency is muted. If you don't know which frequencies relate to the human voice, hit "Preview" and experiment by sliding the dials around. When the vocals begin to disappear from the playback, stop tweaking.
Click "OK" when you've removed the vocals. A progress bar appears to tell you that the audio is being processed without vocals. Once that has disappeared, the audio is ready to be exported as a karaoke song or backing track.