What is the term for the science dealing with frequencies above the limit of human perception?

The term that describes the science dealing with frequencies above the limit of human perception is ultrasonics. Ultrasonics refers specifically to sound waves that operate at frequencies greater than 20 kHz, which is the upper limit of human hearing. This field encompasses various applications, including medical imaging techniques such as ultrasound, industrial cleaning, and non-destructive testing.

In contrast, sonics pertains to sound waves that fall within the range of human hearing, generally from about 20 Hz to 20 kHz. Auditory science focuses primarily on the study of hearing and the auditory system within the limits of human perception, rather than frequencies that are beyond those limits. Acoustic engineering, while related to sound and its properties, typically involves the manipulation and application of sound waves within the ranges that can be perceived by humans or in acoustic environments.

Thus, ultrasonics is the correct term as it specifically addresses the science of higher frequencies, which are not detectable by human senses.