Back in the old days you could remove the vocal from a stereo track by subtracting the left channel from the right.

* You only got mono output,
* The bass was missing,
* The mix sounded terrible,
* You could only remove the vocal, not isolate it.

Voice trap uses a sophisticated FFT algorithm that overcomes all these problems:

* The output is stereo,
* The bass frequencies are left untouched,
* The mix is largely preserved,
* You can choose to remove the vocal OR isolate it.