Mix sounds perfect but changes without interface

Whoever figures this out gets a medal.

My master sounds just as I would like it to but that is when I listen via my interface with monitors or headphone amp. If I disconnect my interface and listen to the WAV normally on my computer speakers or headphones (same ones) and earphones suddenly there are volume, EQ and compression dips; the whole thing just sounds weird and messy. There are no issues with famous songs so obviously it’s me, but I can’t begin to understand what it could be. Totally clueless


If the mix sounds different on a different speakers, you have to re-mix it, or make a proper mastering. Exactly this is an art of Mastering. To make I sounding the same on different speakers.