Room Acoustic Measurements

Room Acoustics

This page provides an overview on the subject of Room Acoustics. We cover the terminology and list the key measurements required to determine the acoustic properties of a room. We also provide links to how each actual measurement is done.

Room Acoustics is distinguishable from Building Acoustics, which essentially deals with the insulation of noise from other rooms or the outside world.

Recommended Solution for Room Acoustics

What do Room Acoustic experts measure?

Room Acoustics is a broad term that describes the acoustic properties of closed spaces. Measuring and controlling this behavior of waves is particularly useful in rooms where the quality of announcement messages and/or music is important, such as in conference halls, classrooms, concert halls, recording studios, airports, and train stations.

There are three main measurements that assist Room Acoustic experts in characterizing the acoustic properties of a room.
Reverberation Time   Speech Intelligibility   Background Noise (Noise Curve)


Why is it necessary to measure?

Rooms with too many or too few reflective surfaces, or too much or too little background noise can affect people’s moods and psyche.

Think of how cold and loud a conversation sounds in a hospital with tiled, reflective surfaces compared to how warm and soft a conversation sounds in a cinema with cushioned seats and walls (of course the purpose of the location has a significant effect on your mood too).

Think of how your mood changes in your office when a heavy construction machine starts up nearby. It is difficult to relax in such a space. Such unnatural-sounding rooms may also make speech difficult to understand, thereby affecting our ability and desire to communicate.

Every room needs to have the background noise under control to make the room fit-for-purpose.

The room should also respond acoustically with an appropriate amount of reverberation. For example, for good speech intelligibility in a classroom, the reverberation time should be around 1 second or less. A classical music concert hall, on the other hand, needs reverberation times of 2-3 seconds to ensure a rich and warm listening experience.


Which measurement kit do you need?

The handheld XL2 Acoustic Analyzer provides you all three measurement functions combined in one device: Reverberation Time, Speech Intelligibility and Noise Curves. Thanks to the simple operation, you can comfortably switch among the three measurement functions, and produce professional reports. All measurements are performed in compliance with your national and international standards.

5 reasons why the XL2 is the right choice for you

XL2 Acoustic Analyzer for Room Acoustics Measurements
  • The XL2 is easy to use.
  • The XL2 automatically detects the sensitivity of the microphone for indisputable accuracy.
  • All measurement results are stored on the removable SD card as TXT files, which can be further processed externally with a PC or MAC.
  • Besides the three Room Acoustic measurements, the XL2 has many other expandable measurement functions. So, if you have other acoustic or audio measurement tasks, it's likely that the XL2 can help you.
  • Together with the Type Approval Option, the XL2 is an approved Sound Level Meter.


DS3 Dodecahedron Speaker Kit

The Dodecahedron Speaker Kit, comprising of the Dodecahedron Loudspeaker and the Power Amplifier, is the measuring equipment designed for professionals for use in their daily measuring tasks in room acoustics. Optimized design, combined with unique precision, low weight and flexible operation establish this equipment as a reference in the marketplace.

  • Acoustically flat frequency response 
  • Maximum sound power level 120.5 dB 
  • Wireless remote control


The XL2 complies to the following standards:

  • Speech Intelligibility STI is measured in accordance with IEC 60268-16:2020 standard as well as older revisions.
  • Reverberation time measurement is defined in the ISO 3382-1 standard for performance spaces and the ISO 3382-2 standard for ordinary rooms, as well as the ASTM E2235 standard.
  • Noise Curves are measured in accordance with the ANSI S12.2-2019, ISO/R 1996:1971 and ASA 1971 standards.

Where to next?

Read more about room acoustic measurements
Reverberation Time   Speech Intelligibility   Background Noise (Noise Curve)


News Articles about Room & Building Acoustics

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