Glossary

A little collection of the most important words from the world of sound. If you understand these, you can discuss sound, even with seasoned sound experts.

Acoustics
Means ‘doctrine of sound’ but the word is most often used to describe the sound conditions in a room.

Alpha value
A name for the sound absorption coefficient that describes how much sound a material or product absorbs. Goes from 0.0 to 1.0 and is abbreviated to ‘a’, ‘aw’, or ‘ap’.

Amplitude
Describes the pitch, which essentially corresponds to the volume or strength of a sound wave.

Audiophile
A person who is very particular about every little thing sounding just right.

Bass
Rumbling or muffled sounds with a low frequency, around 20-200 Hz.

Noise
A relatively constant form of noise pollution.

Noise pollution
All unwanted sounds count as noise pollution. In other words, it’s a question of interpretation where most people are in agreement. And a common misconception is that noise pollution has to be loud.

Decibels
A unit that describes how loudly we experience a sound.

Treble 
High-pitched or sharp sounds with high frequency, approx. 2,000–20,000 Hz.

Reverberation 
Dense sound reflections that linger in a room.

Reverberation time 
A measurement that describes how long it takes for a sound to decrease by 60 dB after the sound has stopped.

Echo
Reflected sound which is perceived as a separate sound due to a short delay.

Frequency 
A sound wave’s number of oscillations per second. Describes the tone of the sound (character).

Hertz
The unit for measuring frequency. 1 Hertz (Hz) means one oscillation per second.

HiFi
Abbreviation of ‘High Fidelity’ or ‘very faithful to the original’. The term is synonymous with high quality when talking about sound systems.

Infrasound 
Low frequency sounds under 20 Hz. Imperceptible to the human ear.

Sound source 
Where the sound is coming from. Could be anything from a speaker or a vocal cord to heels on a floor.

Sound absorption coefficient 
A value that describes how much sound a material or product absorbs. 0 is no absorption and 1 is complete absorption. The value can be translated to a percentage, which means that 0.9 is 90%.

Mach
A measurement that describes the speed of sound in a specific environment. In air temperatures of 15 ° C, this means 340 m/s or 1,224 km/h. Mach 1 is the speed of sound and Mach 2 is twice as fast.

Mid-range 
The frequency range between bass and treble, approx. 200–2,000 Hz. Includes the range for normal conversation levels and is also where our ears are best able to perceive nuances.

Reverb
A persistence of sound after the sound is produced.

Tone
The character of the sound, which is another way of describing the frequency. Light tones have high frequencies and dark tones have low frequencies.

Pitch 
The height of the sound wave, which decides the volume of the sound.

Ultrasound
High-frequency sounds over 20,000 Hz. Imperceptible to the human ear.

Volume
In the context of sound, volume means the same thing as sound strength or sound level. The word is a measure for describing how strong or loud the sound is.