What is THD a measure of in hearing aids?

Total harmonic distortion (THD) is a critical measure in the context of hearing aids as it indicates the level of distortion produced by the device when amplifying sound. Specifically, THD quantifies how much the output sound differs from the original sound wave, typically expressed as a percentage. A lower THD value signifies a cleaner, more accurate sound reproduction, which is essential for users of hearing aids in understanding speech and enjoying music.

For hearing aids, maintaining a low THD is vital for ensuring clear and high-quality sound. High levels of distortion can produce unnatural sounds, leading to listener fatigue, frustration, or an inability to comprehend speech effectively. Thus, THD serves as an important parameter in assessing the performance and fidelity of hearing aids, enabling audiologists and dispensers to make informed decisions about suitable devices for individuals with hearing loss.