Auditory Masking

Auditory masking is one of the most important phenomena in hearing science and has profound implications for sound system design, acoustic measurement, and audio coding. It occurs because the basilar membrane in the cochlea responds to frequency bands, and a strong signal in one band can suppress the neural response to weaker signals in nearby bands.

Simultaneous masking is frequency-dependent and asymmetric: a loud low-frequency sound masks higher frequencies more effectively than a loud high-frequency sound masks lower ones. This "upward spread of masking" means that bass-heavy noise (HVAC, traffic) is particularly destructive to speech intelligibility because it masks the critical consonant frequencies (2-8 kHz) where speech information is concentrated.

Temporal masking extends the masking effect in time. Forward masking (post-masking) causes a loud sound to render quieter sounds inaudible for up to 100-200 ms after the masker stops. Backward masking (pre-masking) is weaker, extending only 5-20 ms before the masker onset. In reverberant spaces, the reverberation from one syllable forward-masks the onset of the next syllable, directly reducing speech intelligibility.

SonaVyx measurements address masking through several tools. The STI measurement inherently captures the effect of masking because the modulation transfer function degrades when masking reduces the audibility of temporal modulations. The SPL meter's octave band analysis reveals the spectral distribution of masking noise. The noise dose calculator tracks exposure to masking noise levels. The AI diagnostic considers masking when evaluating overall system performance, recommending EQ and level adjustments that improve the signal-to-masker ratio in critical frequency bands.