mattkhan
Distinguished Member
BASIC INFO
What is RoomEQ Wizard (aka REW)?
From the help
REW (Room EQ Wizard) is a Java application for measuring room responses and countering room modal resonances. It includes tools for generating test signals; measuring SPL; measuring frequency and impulse responses; generating phase, group delay and spectral decay plots, waterfalls and energy-time curves; generating real time analyser (RTA) plots; calculating reverberation times; 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.
Who is this thread for?
Anyone who wants to get this most out of their subwoofer through the use of objective data to learn about what they listening to and how that relates to what they like.
How do I use this thread?
This thread will contain 2 things
Why should I care about REW?
See here
Where do I get REW from & who else can help me use it?
See here
GETTING STARTED
Is there a step by step guide available?
AustinJerry maintains a guide over on AVS which can be found here. This gives a blow by blow account, with pictures, on how to get started.
What do I need to get started?
See here
What connections do I need to make to use REW?
Refer to this HTS post for full details & the various options for getting ready to measure.
How do I configure REW to use a physical loopback connection (to provide a timing reference)?
A physical loopback provides a means to measure absolute time/phase. See here for configuration details.
How do I configure REW to use an acoustic loopback connection?
REW 5.15 beta 3 has implemented an "acoustic loopback" feature. This sends a high frequency reference signal to a speaker which then acts as the timing reference. This feature can be used to determine relative timing/phase between drivers. Further details can be found in this HTS post
What is the difference between relative phase and absolute phase?
Practically speaking, nothing. Measurements with accurate absolute or relative phase can be summed/compared without issues.
What level (in decibels) should a sweep play at?
See here
DIALLING IN THE SUBS
Is there an alternative to doing this manually?
Yes. Multi Sub Optimiser (MSO) is a powerful free tool that can optimise your setup for you. MSO lives at What Is Multi-Sub Optimizer? and has a thread on AVS at Optimizing subwoofers and integration with mains: multi sub optimizer - AVS Forum | Home Theater Discussions And Reviews
This requires either data with accurate phase data, i.e. requires REW 5.15 beta3 or later for access to the acoustic timing reference or use of a physical loopback.
Approximating a Linkwitz Transform using Shelving Filters and PEQ
See here
Why should I (time) align multiple subwoofers (drivers)?
See here
When using an impulse response to align 2 speakers, what frequency range should I use in the sweep?
See here
How to time align 2 (or more) drivers using REW?
See here
ROOM EQ
How do I work out which room modes I can easily treat with EQ?
See here
Is there an example of working through the whole process?
It spans 2 posts starting here
How do I use REW to calculate PEQ filter(s) that address a single modal peak?
See here
SOUND QUALITY & COMPRESSION TESTING
How do I measure distortion using REW?
See here
What can I do with the information in the distortion graphs?
See here
What effect does the room have on distortion measurements?
See here
How do I measure max useable output?
See here
UNDERSTANDING MEASUREMENTS
What do the "window" controls do?
See here
What is RoomEQ Wizard (aka REW)?
From the help
REW (Room EQ Wizard) is a Java application for measuring room responses and countering room modal resonances. It includes tools for generating test signals; measuring SPL; measuring frequency and impulse responses; generating phase, group delay and spectral decay plots, waterfalls and energy-time curves; generating real time analyser (RTA) plots; calculating reverberation times; 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.
Who is this thread for?
Anyone who wants to get this most out of their subwoofer through the use of objective data to learn about what they listening to and how that relates to what they like.
How do I use this thread?
This thread will contain 2 things
- any and all discussion about REW that people want to have
- a FAQ about using REW to setup a subwoofer
Why should I care about REW?
See here
Where do I get REW from & who else can help me use it?
See here
GETTING STARTED
Is there a step by step guide available?
AustinJerry maintains a guide over on AVS which can be found here. This gives a blow by blow account, with pictures, on how to get started.
What do I need to get started?
See here
What connections do I need to make to use REW?
Refer to this HTS post for full details & the various options for getting ready to measure.
How do I configure REW to use a physical loopback connection (to provide a timing reference)?
A physical loopback provides a means to measure absolute time/phase. See here for configuration details.
How do I configure REW to use an acoustic loopback connection?
REW 5.15 beta 3 has implemented an "acoustic loopback" feature. This sends a high frequency reference signal to a speaker which then acts as the timing reference. This feature can be used to determine relative timing/phase between drivers. Further details can be found in this HTS post
What is the difference between relative phase and absolute phase?
Practically speaking, nothing. Measurements with accurate absolute or relative phase can be summed/compared without issues.
What level (in decibels) should a sweep play at?
See here
DIALLING IN THE SUBS
Is there an alternative to doing this manually?
Yes. Multi Sub Optimiser (MSO) is a powerful free tool that can optimise your setup for you. MSO lives at What Is Multi-Sub Optimizer? and has a thread on AVS at Optimizing subwoofers and integration with mains: multi sub optimizer - AVS Forum | Home Theater Discussions And Reviews
This requires either data with accurate phase data, i.e. requires REW 5.15 beta3 or later for access to the acoustic timing reference or use of a physical loopback.
Approximating a Linkwitz Transform using Shelving Filters and PEQ
See here
Why should I (time) align multiple subwoofers (drivers)?
See here
When using an impulse response to align 2 speakers, what frequency range should I use in the sweep?
See here
How to time align 2 (or more) drivers using REW?
See here
ROOM EQ
How do I work out which room modes I can easily treat with EQ?
See here
Is there an example of working through the whole process?
It spans 2 posts starting here
How do I use REW to calculate PEQ filter(s) that address a single modal peak?
See here
SOUND QUALITY & COMPRESSION TESTING
How do I measure distortion using REW?
See here
What can I do with the information in the distortion graphs?
See here
What effect does the room have on distortion measurements?
See here
How do I measure max useable output?
See here
UNDERSTANDING MEASUREMENTS
What do the "window" controls do?
See here
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