All voice cancellers share the same limitations. They are dependent on what cd or mp3 is being played. Voice cancellers work by eliminating what is in the center channel, which is usually the vocal. With all of the different modern production methods, vocals are not always dead center in the mix. The vocal may have many effects, or there may be several vocals mixed together. All of these factors play a huge role in how well a voice canceler will be able to do its job. Some music will work great, and other songs will not.