REW

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.

Downloads

OS	Downloads
Win 11/10/8/7 Vista 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. You may need to use the mac's Privacy settings to grant REW access to the folders where measurements are to be saved, particularly if they are on the desktop.
AMD64	Linux AMD64 installer (50.3 MB, includes private Java 8 AMD64 runtime)
	Linux installer (30.4 MB, requires a Java 8 runtime)
All	Sampledata.mdat (8.0 MB) Sample measurement data

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 (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).

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

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

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

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

Links

• Official REW Forum at AV NIRVANA
• Presentation on REW to the AES Melbourne section, August 2022
• Thread on REW setup with USB mics and HDMI on AVS Forum
• Thread on how to set up your Mac for REW
• REW help tradotta in Italiano
• Gearspace Studio Building / Acoustics forum
• Equalizer APO system-wide parametric equalizer for Windows 7 / 8 / 8.1 / 10
• Multi-Sub Optimizer
• Convolver plug-in
• Texas Instruments Audio Characterization Primer using REW
• miniDSP acoustic measurement application notes
• REW uses the install4j multi-platform installer builder
• TradeFair.audio, a great collection of audio tools, papers, jobs, blog posts and more

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

Equipment

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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