Final answer:
The difference in level between the softest and loudest parts of a signal is the dynamic range and is measured in decibels (dB). The volume corresponds to sound wave amplitude, and loudness is also influenced by frequency, with the ear being more sensitive at certain frequencies.
Step-by-step explanation:
The difference in level between the softest and loudest parts of a signal is known as its dynamic range. This range is measured in decibels (dB), which is a logarithmic unit of sound intensity. The amplitude of a sound wave, which is the height of the wave from peak to trough, correlates with the volume that we perceive. Louder sounds have greater amplitude, thus a higher decibel level, compared to softer sounds. For example, a normal conversation typically measures around 60 dB, while a rock concert may reach levels of 120 dB.
Additionally, the loudness of a sound does not depend solely on amplitude but is also influenced by frequency. The human ear is more sensitive to certain frequencies, particularly those between 2000 to 5000 Hz, and less sensitive to sounds at the high and low ends of the hearing range.