Human ears are most sensitive to frequencies around 2,000 to 5,000 cycles per second. That’s the most useful range for hearing human speech.
But music can encompass sounds down to about 20 cycles and up to 20,000. We just can’t hear the highs and lows as well as the middle. Strangely, the louder the music, the better we hear the lowest and highest sounds. In fact, we get the fullest spectrum of sound as close as possible to the threshold of pain.