The connection between low frequency overhang and listening fatigue is not immediately obvious, because the fatigue produced by excess bass is different in character from the more familiar fatigue caused by high-frequency harshness or upper-midrange emphasis. It is slower in onset, more diffuse in its symptoms, and more likely to be attributed to the wrong cause.
High-frequency fatigue is acute — it manifests within minutes as a specific sharpness or edge that the listener can identify and locate spectrally. Low-frequency fatigue is cumulative. A session that begins with a warm, full sound gradually becomes heavy and congested. The music begins to feel effortful to follow. Detail that was initially discernible becomes obscured. The listener finds themselves turning down the volume not because the sound is harsh but because it feels oppressive — as though the room is filling with sound rather than reproducing it.
The mechanism is related to masking. As the session continues, the room’s modal energy accumulates — each successive bass note adds to the residual energy already present from previous ones. At normal musical tempos, the interval between bass events is short enough that the room’s modal decay has not completed before the next event begins. The bass region of the room becomes a continuous, fluctuating layer of stored energy rather than a sequence of discrete, decaying events. The listener’s auditory system — attempting to track and separate the musical signal from this background — expends increasing cognitive effort, and the subjective experience is fatigue.
Transparency is the simultaneous casualty. Transparency in audio reproduction refers to the listener’s ability to hear through the system to the recording — to perceive the acoustic space of the performance, the texture of individual instruments, and the subtlety of the recording’s dynamic range. Low-frequency overhang directly compromises this by introducing a layer of non-musical energy between the listener and the recording. The system stops being a window onto the performance and becomes a colouring agent — adding a persistent bass character that belongs to the room, not to the music.
The paradox is that a room with significant overhang can initially sound impressive — full, powerful, and physically present. It is only over time, and in comparison with a well-controlled room, that the cost becomes apparent. What sounded like richness was obscuring detail. What felt like presence was masking transparency.