Masking Effect & Audibility

The masking effect is a phenomenon in which the presence of one sound (the masker) can reduce the audibility of another sound (the masked sound).
In acoustics, this effect is particularly relevant in the context of low-frequency sounds and distortion audibility.

Key Points:

Here is how it mask from a fundamental:

masking-effect

We also need to couple this to ear sensitivity according to frequency and SPL (aka volume level) for audibility purpose :

ears sensitity
The bottom red line represent the sensitivity threshold of the human ear.

It is also necessary to take into account that we live in a permanent and measurable background noise, if a sound or distortion due to a higher SPL level harmonic is found in the background noise, it will be less or even inaudible.

Pierre-Yohan Michaud combined all these aspects in his thesis “Distorsions des systèmes de reproduction musicale : Protocole de caractérisation perceptive” (Distortions in Music Reproduction Systems: A Protocol for Perceptual Characterization):

ears sensitity

We can see in this example that H3 is in the audible range, whereas H2 is in the masking effect.

Example:

If you boost the bass in your music system, you may notice that the vocals become less clear. This is because the boosted bass is masking the higher-frequency vocals.

To mitigate the masking effect:

Warning:

Do not try to correct ear sensitivity, the brain is adapted to ear sensitivity curve, you will unbalance and risk to damage your internal ears in high frequency (hearing loss and tinitus).

A speaker mus be flat at 30/60cm as see here : how to implement my horn and my speaker

sources:

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