This is a question that we get asked quite regularly, especially from customers who are coming across the measurement of reverberation for the first time.

I recently came across a simple, clear explanation that was written by Harout Taghilian who is an Acoustic Consultant at Ramboll.

Harout wrote:

A lot of people are confused about the difference between reverberation and an echo.

Reverberation is the persistence of sound after the sound source has been stopped. It results from a large number of reflected waves which can be perceived by the brain as a continuous sound.

On the other hand, an echo occurs when a pulse of sound can be heard twice. It is normally assumed that if there is a delay of 50ms or more between the first and the second sound reaching the ear, then they will be perceived by the brain as separate events rather than one extended event.

I hope the above explanation is a simple and a clear one.

Here’s a simple diagram that helps to explain this:

Did you know?

The Cirrus NoiseTools software has an extension module that allows for the calculation of Reverberation Time (RT60, 30 & 20) in accordance with EN ISO 3382-2 using data that has been measured using an Optimus Sound Level Meter.

The module provides:

• Calculation of reverberation time using measurements from an Optimus sound level meter
• Automatic detection of suitable data using EN ISO 3382-2:2008¹
• Calculation of RT20, RT30 and RT60
• Can be used with Interrupted or Impulse noise source data
• Graphical & numerical display of calculated values
• Verification of calculations in accordance with EN ISO 3382-2:2008¹

¹ EN ISO 3382-2 Acoustics – Measurement of room acoustic parameters – Part 2: Reverberation time in ordinary rooms (ISO 3382-2:2008)

If you would like more details of this module, please get in touch and we will be pleased to help.