808 sample packs often sound distorted because they’re made up almost entirely of low-end frequencies. To solve this problem, it’s important to mix the sample properly with the other instruments in a song.
808s can also sound distorted if your headphones or speakers are set to vibrate too much in response to bass frequencies (Overtones). Vibrating Low Frequency waves transport energy through air cavities and into solid materials by exerting pressure on them, however, there is an upper limit for how much you can transfer power before things break down. So if your music sounds good on speakers but terrible when listening via headphones it could be that the frequency requirements exceed what most devices are able to playback without distortion.