Not all mp3 codecs are the same, and some include a feature called perceptual compression. Thus, the predominate features of the audio one actually hears are pr

Not all mp3 codecs are the same, and some include a feature called perceptual compression. Thus, the predominate features of the audio one actually hears are preserved over high-frequency overtones most people find unpleasant. Thus, the self-similarity of the small file is improved, while the perceived sound quality is better at lower bit-rates (note not all psychoacoustic models are the same). This is why some encoders sound like garbage even at relatively high encoded quality levels. Lets be clear, most people can't hear the difference (e.x. digital synth music makes smaller files with duplicate audio), and others simply adapt to poor sound quality given they hit the $2.34 hardware mixer chip interpolation limitations long before the audio codecs limits (e.x. Bluetooth can be really iffy). Don't worry about it, and maybe pick up a stringed instrument if you want a quality experience =3