Poweramp player is specifically ignored by the Equalizer app as both DVC implementations will conflict. It’s still technically possible, but Poweramp Equalizer is focused on 3rd party players - Spotify, Deezer, GPM/YTM, etc. Poweramp itself has enough (or even more:-) ) equalization and DSP, and some Equalizer features will be ported back to player (for example, configurable number of bands).