Sound, Frequency and the Body — What Physics Says, What Physiology Says, What Metaphor Adds

One word, several worlds

'Frequency' is one of those words that changes meaning depending on the room. In physics, it has a precise definition: the number of cycles of a periodic event per unit of time, usually measured in hertz. In music, frequency relates to pitch. In neuroscience, frequency can describe rhythmic patterns in electrical activity. In everyday spiritual language, people may use 'high frequency' to describe an emotional or moral state.

Problems begin when a metaphorical use is presented as though it were automatically a physical measurement.

What sound is

Sound is a mechanical wave travelling through a medium such as air, water or tissue. A vibrating source produces pressure changes. Frequency contributes to perceived pitch; amplitude relates to intensity, though human perception is more complicated than a one-to-one mapping.

The human auditory system converts these physical variations into neural signals. The body is therefore genuinely responsive to sound - not because every tone is mystical, but because hearing is biology.

Rhythm and entrainment

Brains and bodies contain rhythms: breathing, heartbeats, sleep cycles and patterns of neural activity. External rhythmic stimulation can interact with perception and movement. People naturally synchronise tapping or walking to a beat. Neural activity can also track rhythmic features of speech and music.

Scientists use the term entrainment in specific ways to describe synchronisation or phase relationships between oscillatory processes. This is a real research field, but the existence of entrainment does not mean any chosen frequency can produce any chosen mental state.

Binaural beats

Binaural beats occur when slightly different tones are presented separately to each ear, producing the perception of a beat at the difference frequency. They have been studied for effects on EEG activity, anxiety, attention and other outcomes.

A systematic review of EEG studies found inconsistent results for the strong claim that binaural beats reliably entrain brain oscillations. Some studies supported the hypothesis, more did not, and methods varied substantially. Newer clinical reviews report some promising outcomes in specific contexts, but heterogeneity and small studies remain major limitations.

The correct conclusion is not 'binaural beats do nothing' or 'binaural beats reprogram the brain'. It is that the evidence is mixed and still developing.

The problem with magic numbers

Online posts frequently assign universal biological powers to single frequencies such as 432 Hz, 528 Hz or other 'healing frequencies'. Music tuned to different reference pitches can certainly sound different, and personal preference can influence relaxation. But there is no accepted scientific basis for claiming that one isolated tuning frequency universally repairs DNA, opens consciousness or heals disease.

A frequency number looks scientific because it is measurable. A measurable number, however, does not make every story attached to it scientific.

Resonance is real - and specific

Resonance is another word that travels between physics and metaphor. In physics, systems can respond strongly near particular natural frequencies under defined conditions. Musical instruments are obvious examples. Buildings, bridges and mechanical systems have resonant properties too.

When someone says a story 'resonates with me', that is metaphor. It may be beautiful and accurate as language, but it is not evidence that two human energy fields have entered mechanical resonance.

Music can still matter enormously

Rejecting exaggerated frequency claims does not reduce music to nothing. Music can influence arousal, emotion, attention, memory, movement and social bonding. Rhythm can support coordinated exercise or rehabilitation. Familiar songs can evoke autobiographical memories. Sound environments affect stress and concentration.

The mechanisms are richer than a single number.

A clean four-layer model

For Madame Monsieur, sound is easiest to explore in four layers.

Physics: what wave is present and how is it measured?

Physiology: how does the ear, brain and body respond?

Psychology: what does the listener perceive, remember or feel?

Culture and metaphor: what meanings have people attached to the sound?

All four layers can be interesting. Confusion begins only when one is used as proof of another.

The studio question

Maybe 'frequency' became culturally powerful because it offers a dream of translating invisible experience into a number. If mood, love, fear or consciousness had a frequency, perhaps they would feel measurable and controllable.

But what do we lose when metaphor is forced to pretend it is physics - and what becomes possible when we allow both to remain in their own languages?