Sound Quality problem

I’m using MacBook Pro and the sound is limited severely even when the limiter is turned off in preferences.
I thought it was my Numark four deck controller that was the problem. And although this has its own issues of not being fully compatible so therefore going into demo mode and inconsistent volume levels, I’ve since bought a pioneer DDJ FFx4 and sound is poor!! Always low and muddy.
When I play straight from iTunes it’s crystal clear and correct volume.

This is about to force me to have to go to a competitor.

I use this for work so this is a huge issue. I can’t play big clubs or spaces with this issue. @Lukas if you are the faults guy can you get this sorted. I’ve seen comments as far back as Feb 2016 saying the same thing.
The software must match or exceed the quality you get with serato! Or I will have to change streaming service as well as DJ software