|This page describes techniques which on some stereo tracks may allow you to remove or isolate vocals (or other parts of a recording) from the rest.
Third-Party Plug-ins for Vocal Removal & Isolation
As well as the above methods supported in Audacity itself (see Vocal Removal and Isolation in the manual) there are various third-party plug-ins that can be used to try and remove or isolate vocals.
Center Pan Remover (Vocal Remover)
There is a Nyquist plug-in called Center Pan Remover‡ which automates the steps involved in Case 1 above. It also has an option to set a slider to "0 (band)" then choose specified frequencies to remove, instead of inverting the whole of one channel. This may be less destructive of the non-vocal parts of the music.
To install this plug-in, place "centerpanremover.ny" in the Plug-Ins folder inside the Audacity installation folder. On Windows, the Audacity installation directory is normally at C:\Program Files\Audacity ( or C:\Program Files\Audacity 1.3 Beta (Unicode) in legacy 1.3 versions ). On 64-bit Windows this directory will be "Program Files (x86)" then as appropriate. On OS X, the Audacity installation directory is normally under /Applications. On Linux see here.
After restarting Audacity, select the track or audio you wish to remove the center-panned elements from and click(it will be underneath the divider in the Effect Menu).
Note that although two channels of output are produced, the result is mono because both channels will be panned to centre.
Windows VST Plug-ins
There are several Windows VST plug-ins that can be used in Audacity for vocal removal and isolation. For installation of VST plug-ins, see below.
- kn0ck0ut (free) can sometimes remove vocals where they are not centre-panned but rather different in frequency make-up compared to the non-vocal parts of the track. It works on two mono tracks (split from a stereo track and made mono as above) by extracting the right channel frequencies from the left hand frequencies, leaving the "result" in the former left channel. Alternatively, if your vocals are centre-panned, this plug-in can often make a good job of isolating them from everything else.
- Voicetrap is a commercial plug-in featuring centre channel removal by frequency-based and cepstral methods (that is, not a simple subtraction of one channel from the other). It has an advantage over kn0ck0ut of providing stereo output for the "vocals removed" track, as well as offering isolation of centre-panned content. There is a demo version with a "mild" vocal removal setting (but no isolation ability) that works in Audacity.
- Brainworx have a free (registration-required) VST plug-in bx_solo (download link here) that lets you solo mid and side channels so provides opportunity for vocal isolation or removal in the right circumstances.
- There is a commercial VST plug-in called ExtraBoy which offers useful functionality for those interested in vocal removal or modification of the different components of an audio track. There are two versions of this plug-in, but unfortunately neither work properly with the currently limited VST support that Audacity can offer. It seems that the processed audio is always completely silenced irresepective of the plug-in settings used. Both versions of ExtraBoy do function with other audio editors which offer full VST support, so you could always export a track from your Audacity Project as a WAV or AIFF file and process it in Extraboy in another editor.
The "lite" version of ExtraBoy is quite similar to VoiceTrap but offers some vocal removal ability on all tracks (not just on centre-panned vocals). It has two "vocal removal" algorithms (1) on the basis of the vocals' frequency characteristics, and (2) on the basis of their spread in the stereo spectrum. The two algorithms can be combined to obtain the best possible removal in a particular case, and full stereo information is preserved in the processed track. A "vocal isolation" algorithm is also provided.
The 14 day full-featured "demo" version claims to be capable of isolating, removing, suppressing or enhancing any component of a stereo track, based on its identified frequency and spatial "signature". Naturally the author points out that the exact results are subject to the particular characteristics of each track. Multiple components of a track can be processed simultaneously (for example, to isolate piano and vocal, or enhance piano and bass).
OS X Plug-ins
- There is an voxReducer PPC Audio Unit plug-in (14 day free evaluation) you can try in current Audacity. It requires Mac OS X 10.4 to 10.6 (using Rosetta on an Intel Mac). It will not work on OS X 10.7 or later as there is no PPC support.
VoxReducer is similar to the Nyquist Center Pan Remover in that it aims to reduce the strength of centre-panned vocals, but differs in having a phase offset adjustment and a slider for adjusting the intensity of the vocal reduction. Place the voxReducer.component in either /Library/Audio/Plug-ins/Components or ~/Library/Audio/Plug-ins/Components.
- Brainworx have a free (registration-required) VST or Audio Unit plug-in bx_solo (download link here) that lets you solo mid and side channels so provides opportunity for vocal isolation or removal in the right circumstances. See voxReducer above for Audio Unit installation or below for VST installation.
VST Plug-in Installation
To add VST plug-ins to current Audacity (or legacy 1.3.8 or later), place the plug-in's unzipped .dll or .dylib file in Audacity's Plug-ins folder or in a system location where Audacity looks for VST plug-ins. Then go to the , choose on the left, put a checkmark in "Rescan VST effects... ", click OK and restart Audacity. The new plug-ins will appear underneath the divider in the Effect Menu. See detailed instructions here. Audacity will display the full interface for VST plug-ins that have a graphical interface.
In legacy Audacity prior to 1.3.8, place the plug-in's unzipped .dll or .dylib file into Audacity's Plug-ins folder, together with the extracted vst-bridge.dll or vst-bridge.so from the Audacity VST Enabler. Then restart Audacity. Plug-ins may also be placed in a system location as long as the VST Enabler is installed in Audacity's Plug-ins folder. The new plug-ins will appear underneath the divider in the Effect Menu. See detailed instructions here. Should vst-bridge.dll not work, try the previous VST Enabler for Windows instead of the one linked to above. VST plug-ins in legacy 1.3.8 or earlier only have a generic tabular interface due to licensing restrictions imposed by Steinberg.