ZeroSound - for PowerAmp

ZeroSound allows you to control your PowerAmp playlist with voice commands.
It's useful in situation where you can't use your hands.

I personally use this while longboarding, because I have to wear thick gloves.
The only thing you need are ear plugs with a microphone.

Supported commands are :
- raise / lower the volume
- set the volume to X / volume X (the number has to be in the last position)
- play music / resume playback
- stop the music
- next
- previous
- shuffle

This app doesn't require you to install anything special (besides PowerAmp obviously) :
- No need to root
- No need for Xposed

However, it's using Google Now for the voice recognition part, so you do have to enable an Accessibility Service (as shown in the screenshots above).
You have to enable the service before you can use ZeroSound : Settings -> Accessibility -> ZeroSound
You also have to enable "Ok Google" everywhere, as explained here : http://www.cnet.com/how-to/quick-tip-get-ok-google-everywhere-right-now/ .

When both things are done, you can use voice commands to control PowerAmp using "Ok Google".
Ex : "Ok Google" *wait for the beep* "set the volume to 75"

Note that the app is in a beta state, UI is very ... simple, to say the least, commands are hard-coded (for now), but it works for me.

This is completely free, open-source, ad-free, and has no unnecessary permissions.
Feel free to take a look at the source code : https://github.com/kamek-pf/ZeroSound