REW room acoustics measurement and analysis

Measure rooms, speakers, subwoofers and audio devices with free professional-grade tools and find a path to better sound.

REW helps you optimise the acoustics of your listening room, studio or home theater; find the best locations for your speakers, subwoofers and listening position; analyse the performance of the whole audio reproduction chain and configure EQ to help tackle room problems.

V5.40 wavelet spectrogram, 3D view


The Pro upgrade offers simultaneous measurement of multiple inputs with rms averaging, adjustable weighting for each input, level alignment, and up to 16 input traces on the RTA in addition to the rms average.

It can also calculate Speech Transmission Index from the impulse response by the indirect method per IEC 60268-16:2020.

V5.40 multi-input measurement

Downloads

The current version is V5.31.3, 25th July 2024. Previous builds are here.
Beta version downloads are hosted at AV Nirvana, home of the REW support forum.
To view the REW revision history click here.
OS Downloads
Windows
Win 11/10/8/7
Vista
XP Pro x64
 Windows 64-bit installer

Windows 32-bit installer
MacOS
10.15 - 14
 macOS universal binary
Notarized universal binary for Intel and ARM Macs. You may need to use the mac's Privacy settings to grant REW access to the mic and to the folders where measurements are to be saved, particularly if they are on the desktop.
Linux
AMD64
 Linux AMD64 installer
Linux Linux installer (requires a Java 8 runtime)
All Sampledata.mdat

Donations

If you find REW useful you can make a donation by clicking the button below. Many thanks to those who have already donated, your generosity keeps REW development going and is greatly appreciated.



Help Files

The REW room acoustics software contains comprehensive help information. You can also view the help files online, download the html files for offline viewing or download a PDF copy (V5.20, Sep 2021, courtesy of Steve Bolser). Online help for the current beta version can be found in the Beta help files. The most up to date help files are those online and in the application itself, PDF files are snaphots of the help on the date they were generated. For additional tips and assistance in using the software visit the AV NIRVANA REW forum.

Patrick Del Basso has generously provided a French translation of the V5.20 help file (Jan 2022): REWhelp-V5.20-fr.pdf.

Johnson Chow of Initial Audio Concept has generously provided a Chinese translation of the V5.20 help file (Oct 2021): REW帮助手册-中文版.

Equipment

If you click on the links below and make a purchase, I may earn a small commission at no extra cost to you.

The simplest configuration for most acoustic measurement purposes is a calibrated USB microphone (miniDSP's UMIK-1 is recommended) and your computer's headphone or HDMI output. UMIK-2 is a higher performance USB microphone (lower noise floor, higher sample rates, better clock stability) but is much more expensive than UMIK-1. An analog measurement microphone (Dayton Audio's EMM-6, for example) may be cheaper but will need a suitable interface with a mic preamp and phantom power, such as the Focusrite Scarlett 2i2. Using an analog mic may be more flexible for tasks such as speaker design.

Measurement results can guide changes to the listening setup and room environment. EQ can then help improve the sound at the listening position, subject to some limitations. Many AV receivers have EQ capabilities, whilst standalone devices may offer more features. The miniDSP 2x4 HD, Flex and SHD are examples of standalone solutions with extensive audio processing, including Dirac Live built-in for the more sophisticated (and expensive) offerings. If your sound system is computer-based your media player is likely to offer lots of EQ options, Dirac also offer a computer-based solution.

The table below has shopping links for some of the products mentioned. If you click and make a purchase, I may earn a small commission at no extra cost to you.

miniDSP UMIK-1 calibrated USB measurement microphone
View on Amazon
View on soundimports.eu
View on miniDSP.com
 miniDSP UMIK-1 calibrated USB measurement microphone
miniDSP UMIK-2 calibrated USB measurement microphone
View on Amazon
View on soundimports.eu
View on miniDSP.com
 miniDSP UMIK-2 calibrated USB measurement microphone
Dayton Audio EMM-6 calibrated analog measurement microphone
View on Amazon
View on soundimports.eu
 Dayton Audio EMM-6 calibrated analog measurement microphone
Focusrite Scarlett 2i2 USB audio interface
View on Amazon 		Focusrite Scarlett 2i2 USB audio interface
miniDSP 2x4 HD DSP / Equaliser / USB DAC / crossover
View on Amazon
View on soundimports.eu
View on miniDSP.com
 miniDSP 2x4 HD DSP / Equaliser / USB DAC / crossover

Videos

Linked below are a small selection of third party videos that may be helpful when getting started with REW.

How to Use Room EQ Wizard part 1, setup and taking measurements (by Music City Acoustics)

How to Use Room EQ Wizard part 2, analyzing acoustic measurements (by Music City Acoustics)

A series of videos in German by Florian Grimm covering a range of topics

REW Schritt-für Schritt

A short video tutorial in German (also available in English, both by Marcel Schechter)

Room EQ Wizard (REW) Tutorial German - Einmessung von Lautsprechern mit REW

A video tutorial in German about subwoofer level and phase alignment (Pegelanpassung & Phasenlage für Subwoofer mit Bass Management by Marcel Schechter)

Room EQ Wizard (REW) Tutorial German - Pegelanpassung & Phasenlage für Subwoofer mit Bass Management

A comprehensive guide in French by Adrien Perinot (Projet Home Studio)

2022 REW Seminar (Overview and room treatment process demonstration) in Korean by Sinlyul Lee

2023 REW Seminar (Advanced Acoustic Theory) in Korean by Sinlyul Lee

Recommended Reading

The table below has links to books about acoustics and optimising reproduction. If you click and make a purchase, I may earn a small commission at no extra cost to you.

Master Handbook of Acoustics, Sixth Edition
View on Amazon
 Master Handbook of Acoustics, Sixth Edition
Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, Third Edition
View on Amazon
 Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, Third Edition
Home Recording Studio: Build It Like the Pros
View on Amazon
 Home Recording Studio: Build It Like the Pros
Optimal Audio and Video Reproduction at Home
View on Amazon
 Optimal Audio and Video Reproduction at Home


Reference Material

  • Guy-Bart Stan, Jean-Jacques Embrechts, Dominique Archambeau, "Comparison of different impulse response measurement techniques", JAES Volume 50, Issue 4, pp. 249-262, April 2002. Available online at https://gstan.bg-research.cc.ic.ac.uk/JAES_Online_version.pdf
  • Swen Müller, Paulo Massarani, "Transfer-Function Measurement with Sweeps", JAES Volume 49 Issue 6 pp. 443-471, June 2001. An extended version of the paper is available at Semantic scholar
  • Angelo Farina, "Simultaneous measurement of impulse response and distortion with a swept-sine technique", 108th AES Convention, February 2000. Available as entry number 134 in this list of papers
  • Nikolaos M. Papadakis and Georgios E. Stavroulakis, "Low Cost Omnidirectional Sound Source Utilizing a Common Directional Loudspeaker for Impulse Response Measurements", Appl. Sci. 2018, 8(9), 1703; Available online at https://doi.org/10.3390/app8091703

John Mulcahy is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.