MxRR-Fan Song Mixer

The Fan Song Mixer allows you to create your own mix of the song. On each music track you can Mute, Solo, move left or right, or change the volume of the whole track. There is also on track volume automation.

See image below and try out the features by clicking or tapping on them.

Click the Play button top left to start the mixer.
The title of the track is on the left like "Lead Vocal". The wave image of that track is on the right. 
M = Mute: Stops the track from being heard.
S = Solo: Makes this track the only track heard.
Track Volume: On the line below the title move the dot left or right to change the volume of the whole track.
Channels: Each track is stereo meaning there is left and right audio. Move the dot towards the L or the R and hear that track move between your left and right speakers.
On Track Volume Automation: Click or tap on the pink line you see on each track. A dot will appear on the line. Click again to the left, then in middle. Now click the middle dot you created and drag it up or down. This will change the volume in that section.
Try the mixer here: MxRR for Justified