Hi, if you're using AIMP, you probably want to use the DSP plugin version of Stereo Tool which can run _inside_ AIMP. I don't know if VirtualDJ supports plugins, but if a program doesn't, then you need a program like Virtual Audio Cable (paid) or VB Cable (free) to route audio from another program to Stereo Tool. In the other program, choose for example "Virtual Cable 1" as the output sound card, and in Stereo Tool, choose that same virtual cable as input. These programs basically create a virtual sound card, that you can output to and input from.
For VirtualDJ, I quickly googled and found this post:
https://www.virtualdj.com/forums/178846 ... al_dj.html