MacBook Pro Logic Pro X audio interface poor sound quality

Hi, I’ve been using Logic Pro X for a while now along with a PreSonus Studio Mobile audio interface. I use an amp between the interface and speakers and also very good headphones as and when needed. Sound quality has appeared fine. However, I’ve now I’m listening to my songs on different devices in order to better understand the quality of my mixes. I notice that playback directly through interface into headphones gives ve

ry poor sounding results. Also bounces and emailed projects played back on other devices is equally poor. So, I’m guessing use of the amp is falsely distorting the sound of my mix. But I cannot believe the sound quality can be so poor directly out of the interface into headphones. Am I missing something? No distortion or latency just really lo-fi and flat.

Thoughts very much appreciated.

MacBook Pro 2012 8gb

Presonus Studio mobile

NI Maschine

AKG headphones