DDJ-400 Poor headphone sound output (but good when playing directly from laptop)

Hi!

I've recently bought the DDJ-400 and I am using a simple headset plugged into the controller. However, the sound coming though the headset is terrible. It sounds like its missing all of the bass and a lot of mid tones. I am using a Macbook Pro with Mac Os Big sur v11.4 and Rekordbox v6.5.3.

Now I've tried a lot of different things but I can't get it to work. Here is a list of things I tried:

- I've tried plugging my headphones in my laptop to listen if the sound quality was good when there is no controller in between. (it is)

- I've tried playing around with the buffer size and the sample rate settings.

- I've tried other headphones, the sound is bad on every device. 

- I've tried another laptop (windows). Same result there. 

- I've tried different mp3 quality tracks and from different sources (downloaded, soundcloud go+) 

The master output sound is good, so it is just the headphones output that has problems. 

I have no idea what is wrong, it sounds like the headphone output is broken but I doubt thats the case. Do you have any idea what is going on and how to fix this? 

Thanks in advance,

Ryan Smith