Aeronk i've just upload you backing track and put it through audcity ,your track is running at minus 12db which is way to low, then i run them at 0.0 db null both tracks where peaking out, so the gain record level was too high when the track was first recorded
its not volume its the recording level it was recorded it at ,two different things volume and gain the gain is the recording level when you first record the track ,and gain is what you set all your mics and instruments at on a mixing desk 0.0db ,then you turn the volumes up to fit the mix this stops everything from peaking out and distorting