Room Acoustics Software

REW is free software for room acoustic measurement, loudspeaker measurement and audio device measurement. The audio measurement and analysis features of REW help you optimise the acoustics of your listening room, studio or home theater and find the best locations for your speakers, subwoofers and listening position. It includes tools for generating audio test signals; measuring SPL and impedance; measuring frequency and impulse responses; measuring distortion; generating phase, group delay and spectral decay plots, waterfalls, spectrograms and energy-time curves; generating real time analyser (RTA) plots; calculating reverberation times; calculating Thiele-Small parameters; determining the frequencies and decay times of modal resonances; displaying equaliser responses and automatically adjusting the settings of parametric equalisers to counter the effects of room modes and adjust responses to match a target curve.

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.


The current version is V5.31.3, 25th July 2024. Previous builds are here.
V5.19 cannot open V5.20 or later mdat files
Beta version downloads are hosted at AV Nirvana, home of the REW support forum. To view the REW revision history click here.
OS Downloads
Win 11/10/8/7
XP Pro x64
Windows 64-bit installer (51.3 MB, includes private 64-bit Java 8 runtime)

Windows 32-bit installer (51.3 MB, includes private 32-bit Java 8 runtime)
10.15 - 14
macOS DMG (61.1 MB, includes private Java 8 runtime)
Notarized universal binary for Intel and ARM Macs. Mic access is included in the code signature and will be requested if necessary. A mic access prompt for REW can be forced using tccutil reset Microphone from a terminal before starting REW then using a feature that requires mic access, such as the SPL meter
Linux AMD64 installer (50.3 MB, includes private Java 8 AMD64 runtime)
Linux Linux installer (30.4 MB, requires a Java 8 runtime)
All Sampledata.mdat (8.0 MB)
Sample measurement data


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 (12.3 MB) or download a PDF copy (V5.20, 12.0 MB, 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 (10.0 MB).

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 (15.0MB).


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 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)


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
  • 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


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. An analog measurement microphone (Dayton Audio's EMM-6, for example) will need a suitable interface with a mic preamp and phantom power, such as Steinberg's UR22C or the Focusrite Scarlett 2i2.

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miniDSP UMIK-1 calibrated USB measurement microphone:
Dayton Audio EMM-6 calibrated analog measurement microphone:
Steinberg UR22C USB audio interface:
Focusrite Scarlett 2i2 USB audio interface:
miniDSP 2x4 HD DSP / Equaliser / USB DAC / crossover:
US DE (Hong Kong)
Master Handbook of Acoustics, Sixth Edition:
Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, Third Edition:
Home Recording Studio: Build It Like the Pros:
Optimal Audio and Video Reproduction at Home:

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