frequency masking is one thing to consider, this is how mp3s work at choosing what to throw away as a lossy compression. This is to be considered at all stages of production. Like you gain structure.
The mp3 seems normalized but looks to me that you limiter is actually clipping it. lol, I work at -18dbfs. -3 dBfs
-18dBfs is where you should be as transients kick up much higher but only certain metres will actually show this properly. Its well above the noise floor, be it digital domain or analogue. I then I normalize after mix down then multiband compressor to taste. iTunes to make 24 bit wave a 128 mp3 then uploaded.
you can hear the distortion from the bass being too loud halfway but cos of head room and hardware compressor I got headroom left to then normalize it up with out going over 0dB and clipping it, thus keeping the dynamics.
Its about mastering, making a good bass sound and mixing it to. All this adds up.
Good quality monitors are essential to judge these considerations. Try and make bass have a higher harmonic content for it to stand out with out having to make it louder,. ie exciter. This is another option. Do all this right and it will sound great on any speaker, and that is what you should aim for. I
