Sound is a mechanical wave that travels through a medium, and its frequency, or pitch, is measured in Hertz (Hz), representing the number of vibrations per second. Human hearing is typically sensitive to frequencies ranging from about 20 Hz, up to 20,000 Hz, or 20 kilohertz (kHz). Anything outside this audible spectrum is inaudible but can still affect the body. The question of what music frequency is “bad” for humans often conflates structured musical sound with harmful noise, where the true danger lies not in the pitch itself but primarily in the sound’s intensity.
Loudness
Regardless of the frequency, the most common factor determining physical harm to the ear is the intensity, or loudness, of the sound, which is measured in decibels (dB). Damage to the auditory system occurs when sound levels surpass safe exposure limits, not because of a specific musical note. Health organizations, including the World Health Organization (WHO), advise that prolonged exposure to sound at or above 85 dB can cause permanent hearing damage.
Exposure time shortens dramatically as the volume increases; for example, at 85 dB, one can listen for up to eight hours, but a rise of just 3 dB to 88 dB cuts the safe listening time in half to four hours. This damage is mechanical, caused by the excessive vibration that overworks and eventually destroys the delicate hair cells within the cochlea of the inner ear. Once destroyed by excessive noise, these cells cannot regenerate, leading to irreversible hearing impairment.
The initial effect of noise-induced damage might be a temporary threshold shift, where hearing sensitivity is reduced but recovers after a period of rest. However, repeated or single, very intense exposures can lead to a permanent threshold shift, which is lasting hearing loss. Listening to personal audio devices at high volumes, such as 100 dB, can cause damage in as little as 15 minutes of continuous exposure. The intensity of the music is a far greater determinant of physical harm than its frequency.
Frequencies Below Human Hearing (Infrasound)
Infrasound refers to very low-frequency sounds that fall below the 20 Hz threshold of human hearing. While inaudible, these frequencies can still transmit energy through the air and are often sensed as physical vibrations rather than heard. Natural sources include earthquakes, severe weather, and ocean waves, while man-made sources range from large machinery and ventilation systems to wind turbines.
When infrasound is present at high intensities, it can couple with the body, causing specific physiological effects. The extremely long wavelengths of these sound waves can resonate with internal organs and cavities, including the chest. Exposure to high-level infrasound has been reported to cause symptoms such as pressure, nausea, dizziness, and fatigue.
Some studies suggest that exposure can induce feelings of unease, anxiety, or even a sense of fear, which is why certain infrasonic frequencies are sometimes colloquially referred to as the “fear frequency” in entertainment settings. The physical effects are highly dependent on the intensity and the specific frequency, and research into the impact of low-level environmental infrasound remains an active area of study.
Frequencies Above Human Hearing (Ultrasound)
At the opposite end of the spectrum, ultrasound consists of frequencies above 20,000 Hz, or 20 kHz, which are beyond the range of human hearing. Although the general public does not typically encounter high-intensity ultrasound in music, it is used extensively in industrial and medical fields, such as diagnostic imaging and industrial cleaning. High-frequency sounds rapidly lose energy as they travel through the air, so the risk of harm diminishes significantly with distance.
Harm from ultrasound is primarily a concern in occupational settings where exposure is direct and prolonged, or when using focused devices. High-intensity focused ultrasound (HIFU) in medical procedures is designed to intentionally cause localized physical heating and tissue modification or destruction by concentrating sound energy into a small area. This thermal effect results from the absorption of sound energy, which is converted into heat.
In a general environmental context, some devices like pest-control emitters or high-frequency security alarms operate in the upper range of human hearing or into the ultrasound range. These can be particularly distressing to children or animals, whose upper hearing limit often extends higher than that of adults. For the average person, the main risk comes from focused, high-intensity sources that can cause a localized temperature increase in tissue.
Audible Frequencies and Psychological Distress
Within the normal audible range of 20 Hz to 20 kHz, the potential for sound to be “bad” often shifts from physical damage to psychological distress. This discomfort stems from the subjective organization of sound, where specific combinations can create a feeling of tension or instability known as dissonance. Jarring sound combinations or rapid, unexpected changes in frequency can elevate stress and anxiety levels in listeners.
A common debate revolves around the psychological effects of different musical tunings, specifically 432 Hz versus the modern standard of 440 Hz for the note A. Proponents of 432 Hz often claim it is more relaxing and harmonious with natural frequencies, but this effect is largely psychological and cultural, not a physical threat. Some studies suggest that listening to music tuned to 432 Hz may correlate with small, temporary reductions in heart rate or stress, but overall, the effects are subtle and require more extensive research.
Ultimately, the emotional and mental impact of music is highly subjective and depends on personal preference, past experience, and cultural context. While certain patterns of audible sound can induce stress or a feeling of unease, the distress is a response to the sound’s quality and organization, distinguishing it from the permanent physical harm caused by excessive loudness or the non-auditory physical effects of non-audible frequencies.