HUMP is an acoustically engineered technology designed to direct sound wave towards adjacent chamber. When the sound wave travels down to the other end will interfere with the speaker driver diaphragm.

Since the wavelengths of high frequency sound are short compare to the length of the chamber that the phase difference between the incoming sound wave and the speaker driver diaphragm approaches 0 degree (in phase) , so the interference is constructive and allows the speaker driver able to respond more rapidly to the applied high range small signals.

For most bass frequencies, the wavelength is so much shorter than the chamber length that the phase difference approaches 180 degree (out of phase), so the interference is destructive. Since the diaphragm is damped (destructive) in bass range, it responding least strongly to signals near its natural vibration frequency. The lower the frequency, the more efficient the interference and thus allows to delivery a more pronounced mid to low range improving the cohesive audio experience.