RT60s

RT60 is a term used in acoustics to describe the reverberation time of a space. Specifically, it refers to the time it takes for sound to decay by 60 decibels after the sound source has stopped. Reverberation time is a crucial parameter in determining the acoustic quality of enclosed spaces, such as concert halls, lecture rooms, and recording studios. A longer RT60 generally indicates a more reverberant space, while a shorter RT60 suggests a more "dead" or anechoic environment.

The RT60 value is influenced by several factors, including the volume of the space and the absorption characteristics of the surfaces within it. Materials with high sound absorption properties, like soft furnishings and acoustic panels, will reduce the RT60, while hard, reflective surfaces will increase it. The desired RT60 varies depending on the intended use of the space. For example, speech intelligibility is best served by shorter reverberation times, whereas music, particularly orchestral music, often benefits from longer reverberation to create a sense of richness and warmth.

Measuring RT60 typically involves emitting a loud, broadband sound, such as a hand clap or a pink noise burst, and then recording its decay with a microphone. This decay is then analyzed to determine the time it takes to drop by 60 dB. Various standards and formulas, such as Sabine's formula and Eyring's formula, are used to predict and calculate RT60 values. Understanding and controlling RT60 is fundamental to acoustic design.