Frequency Masking
Definition
A psychoacoustic phenomenon where one sound obscures another when they occupy the same or adjacent frequency ranges. In mixing, frequency masking between instruments causes elements to lose clarity and definition, requiring EQ and arrangement decisions to create separation.
In Simple Terms
When two instruments share the same frequency range, they fight each other and both become unclear — like two people talking at the same time. EQ one down where the other lives, and both suddenly become audible.
In Practice
A bass guitar and a kick drum both have significant energy at 80–100 Hz. Without EQ or sidechain treatment, they mask each other, resulting in a muddy, undefined low end. Carving complementary frequency shapes allows both to be heard clearly.
Common Confusion
Frequency masking is not solved by raising volume. If two elements share the same frequency space, the louder one dominates and the other vanishes — turning up the masked element only escalates the conflict. The fix is always carving (cutting EQ in the dominant element where the other lives) or arrangement (keeping competing instruments out of the same range from the start).
Sources & Verification
- Moore, B. C. J. — An Introduction to the Psychology of Hearing (6th ed., chapters on masking)Brill, 2012
- Fastl, H. & Zwicker, E. — Psychoacoustics: Facts and Models (3rd ed.)Springer, 2007
- Izhaki, R. — Mixing Audio (3rd ed., frequency carving chapter)Focal Press, 2017
Last verified: 2026-05-05