How do I get a louder output from the XDJ-Aero?

XDJ Aero sound is VERY LOW

Am I the only one that has noticed that tracks (All 320 mp3 & Wav) played though the XDJ Aero are quite low & the master + gains have to be turned right up to get any real volume & weight  from the XDJ's output

I have burnt the same tunes on CD & played though a mixer & CDJ's to see if it was the tunes themselves but realised it wasn't as they were louder

Is there any way to sort this out & make the the tracks louder in the settings as I have look though the manual but cant seem to find anything to help with this problem

Can anyone please advice,