Beyerdynamic MMX 300 (2nd Generation) vs MMX 330 PRO

The Beyerdynamic MMX 330 PRO are the open-back version of the Beyerdynamic MMX 300 (2nd Generation), and choosing between them will largely come down to which sound you prefer. The two models have a very similar design, similarly high build quality, and very comfortable fits. That said, the difference in enclosure means they reproduce audio very differently. The closed-back MMX 300 have much more low-end but also reproduce a sharper treble range, for a more excited (though potentially fatiguing) sound overall. Meanwhile, the open-back MMX 330 roll off a lot of low-end but have a more subdued treble response. While sound preference plays a big role in a buying decision, it's also worth noting that the MMX 330's open-back design leaks a lot of audio and struggles to provide any passive attenuation of your surroundings, so they're better suited to quiet environments.