Deep relaxation is a wonderful state to be in. When you are relaxed, your body naturally finds regeneration (1). For many people, achieving deep relaxation requires an appropriate setting, typically one of familiarity, comfort, and trust.

The sounds that you hear in the setting are important. Sounds can help stimulate deep relaxation (2). Not all sounds will have the same effect. For example, a fire siren produces a different response than a rainfall or rustling leaves (3, 4).

How Sound Waves Interact with the Body

A sound is the movement of energy travelling through matter, such as air, water, or an object (5). The energy begins at the source as a disturbance of air. That disturbance moves further away from the source as air particles crash into each other, like a domino effect. The further that the sound travels away from its source, the more energy that dissipates, and eventually the sound disappears (6).

When the wave of sound travels far enough to meet our ear drums, our brain interprets it as sound (7). We learn to associate certain sounds with their source and understand their meaning (8). When we hear the sound of water, it is usually associated with safety. When we hear the sound of siren, it is usually associated with an emergency. The sounds we hear help us interpret our environment.

In addition to meeting our ears, sound waves also interact with our bodies. The wave of disturbed air particles meets our skin, just as it would another object. Perhaps you have stood in front of speaker at a rock concert before and felt the sound in your body. Just like any other object (9, 10), our bodies interact with sound (11, 12, 13, 14).

The Magic of Resonance & Reverberation

The particles that make up every object naturally vibrate on their own at a specific frequency (15). When a sound wave meets and matches an object with the same vibrational frequency, a phenomenon occurs called resonance (16). Resonance is what will make a crystal glass hum, or even break, on its own when you play the right note (17).

Resonance also occurs within chambers of air, such as when you blow over the mouth of bottle or pluck the string of a guitar (18). In this scenario, the trapped air resonates when it is matched by a sound of the same frequency (19).

Resonance occurs every day in our bodies (20, 21). The resonance created in our sinuses when we talk is one reason why every person’s voice sounds different (22). Resonance is the reason why you feel a vibration in your face when you hum (23).

Sound waves can also interact with themselves. When sound waves have enough energy to travel a certain distance, yet hit an object or wall before they reach that distance, the sound wave will bounce off that object. This is known as reverberation (24). As sound waves interact with each other, this can create some unique interactions of sound waves within a room.