Simple Explanation

The time it takes for sound reflections in a space to decay and become inaudible after the original sound source stops.

Concise Technical Definition

Reverberation time refers to the time it takes for sound reflections in a space to lose energy and become inaudible after the original sound source has stopped. The standard measurement of reverberation time is ‘RT60’, which quantifies how long it takes for the sound to decay by 60 dB. This is typically measured at various frequencies, as reverberation time can vary for different frequencies. In some cases, acousticians use a 30 dB decay and then double that value to calculate the RT60, often referring to this as T30 for accuracy.

Layman-Friendly Analogy

It’s like when you clap your hands in a big hall—the sound echoes and fades away. Reverberation time is how long it takes for that echo to completely disappear, from the moment you stop clapping.

Industry Usage Summary

Reverberation time is an important measurement in room acoustics, influencing how sound is perceived in environments such as concert halls, theaters, recording studios, and home theaters. A room’s reverberation time can affect clarity and warmth—too much reverberation can make speech hard to understand, while too little can make the space sound dry or lifeless. The RT60 measurement is used by acousticians to optimize the acoustic properties of a room by controlling how long sound lingers after the source has stopped. It is also critical in the design of audio equipment, where ideal reverberation times are often sought for the best listening experience.

Engineering Shortcut

The time it takes for sound to decay by 60 dB after the sound source has stopped, often measured as RT60.

Full Technical Explanation

Reverberation time is the duration it takes for sound reflections in a space to decay and become inaudible once the original sound source has ended. The standard metric for reverberation time is RT60, which refers to the time it takes for the sound pressure level to decrease by 60 dB from its original value. This is typically measured for different frequencies because the time it takes for sound to decay can vary significantly across the frequency spectrum. While RT60 is the standard, some acousticians first measure the time for the sound to decay by 30 dB and then double that value to calculate the RT60, often calling this value T30 for clarity. Reverberation time plays a crucial role in the acoustics of rooms, as it affects how sound is perceived in terms of clarity, warmth, and presence. It is a key factor in the design and optimization of performance spaces, recording studios, and audio systems.