Airborne sound

In the case of airborne sound, air particles are compacted and moved apart, resulting in pressure fluctuations superimposed on atmospheric pressure.

Amplitude

Amplitude is the magnitude of change in a periodically changing variable. The energy of the vibration is proportional to the square of the amplitude (vibration width).

Angular frequency

ω = 2 x π x f

Damping

Damping refers to when energy is withdrawn from sound. This usually happens through dissipation by converting the sound energy to heat through friction.

Deflection

Deflection refers to the behaviour of a building material under load and is differentiated into linear, progressive and regressive material behaviour.

Dynamic stiffness

Dynamic stiffness describes material behaviour under changing loads. It is the ratio between the acting dynamic force and the resulting deflection.

Frequency

Corresponds to the number of waves per unit of time and thus characterises the tone pitch. Frequency is inversely proportional to the vibration time.

Insulation

Sound insulation is usually associated with sound damping, but sound insulation refers to preventing propagation from the sound source to the recipient.

Resonance frequency

After exciting a system capable of vibration so that it vibrates and then leaving it to its own devices, it vibrates in the so-called resonance frequency.

Frequency amplitudes reach the highest value when resonance frequency and disturbance frequency meet.

Resonance frequency is calculated as follows:

Sound

Vibrations in the range of human hearing from 16 Hz to 20,000 Hz in an elastic medium are referred to as sound. Below 16 Hz they are called infrasound. Above the audible limit, vibrations are called ultrasound, or hypersound above 1 GHz.

Static stiffness

Static stiffness is a material property that reflects behaviour under static loads.

Structure-borne sound

Structure-borne sound is the propagation of vibrations in a solid medium. Structure-borne sound frequently spreads over very large distances and is perceived as secondary airborne sound.

Vibration time

The time it takes to complete a full vibration (e.g. pendulum: once there and once back).

Vibrations

Vibrations are the change in time of the reference position of a body.