Buying Guide・2016-06-25

[Acoustics] Discussing Sound Reinforcement Optimization in Transportation PA Systems from the Perspective of the Masking Effect

Industry Insights Download PDF [Written by / Vice President's Office]

In the past, when evaluating PA systems, the classic rule of thumb was to add 15dB of loudness on top of the ambient noise as the system evaluation standard. However, when the environment is already very noisy, broadcasting frequently at high volumes will make the environment uncomfortable. In fact, human hearing is very interesting and has many unique effects, among which the 'masking effect' is a field worth exploring. If utilized properly, it can reduce the broadcast volume while still achieving effective message delivery.

Audio Masking Effect

The masking effect is a physiological characteristic of human auditory perception. Based on scientific research, it basically follows these principles:

．In terms of amplitude: loud sounds mask quiet sounds within the same frequency domain

．In the frequency domain: a stronger signal will mask nearby sounds, masking certain frequencies towards both low and high ranges. Low-frequency masking is less, while high-frequency masking is more; the closer the frequency, the more severe the masking.

．In the time domain: backward masking (post-masking)

．In time-domain composite amplitude: a large preceding spike masks the following one (forward masking) more..