What's new in REW V5.30

V5.30 has moved to a new look and feel, FlatLaf, to modernise the appearance and make it easier to update. Besides the appearance change there is a lot of additional and changed functionality.

Pro version

Further control over averaging has been added.

Audio interface

Sweep measurements

There is now a mode selector for SPL measurements with a choice of Single measurement, Repeated measurements or Sequential channel measurements. Sequential channel measurements allows a selection of channels to be measured one after another.

Measurement modes

There is a Setup button below the mode selection which brings up a list of settings to apply, including a start delay before the measurement starts, a delay to use between repeated or sequential measurements, the number of repetitions for repeated measurements and the channels to measure for sequential measurements.

Measurement mode setup

A number of options have been added to allow faster measurement.

Other measurement-related changes include:


The EQ filters panel layout has changed to a horizontal format with an image of the filter response in the select button and controls that can be revealed with left click and hidden with double click or right click.

EQ Filters Panel, controls showing

EQ Filters Panel, controls hidden

Other features of the new layout include:

The filter adjust graph shows the region selected for correction by fading the graph outside that region. It has a "Graphical filter edit" option which shows circular handles at each filter's centre frequency. The colour of the handles matches the colour of the filter in the EQ filters panel.

Equaliser selection is now split by manufacturer and model as the list was becoming unwieldy:

Equaliser Selector

The Generic, Extended and miniDSP equalisers have gained a Linkwitz Transform filter option and there are a number of new equaliser choices:

Below the main filter adjust graph there are some new graph choices: a group delay graph, showing the measured and predicted group delay, and step responses on the impulse graph.

House curve file selection is now in the Target settings of the EQ window instead of in a preferences panel.The Target settings room curve slopes can be up to +/-12 dB (previously +/-6 dB).

Impulse responses

There are a number of changes to the display and handling of impulse responses. A navigator view below the impulse graph shows the entire response with the currently displayed portion highlighted. The highlighted region can be dragged to reposition the view. Clicking anywhere in the navigator view centres the displayed portion on the click. If the mousewheel is used while the mouse is over the navigator the graph will be zoomed along its time axis, centred on the time axis position of the mouse pointer in the main graph. The navigator replaces the scrollbar, if it is turned off (in the graph controls) the scrollbar will be visible again according to the state of the scrollbars button above the graph. An indicator ("T") at the bottom of the impulse graph shows the position of the timing reference when the measurement was made.

Impulse navigator

The Impulse graph controls now have a button to scale the IR data to apply a specified gain or achieve a desired peak value.

The IR windows dialog has some additional buttons to apply the window selections to the measurements selected in the All SPL or Impulse overlay graphs. Changes to the window settings in the dialog are applied as they are made. There are also additional window shapes: Cosine, Tukey 0.5 and Tukey 0.75. The choice of cycles or octave fractions for the frequency dependent window units is now in the Analysis preferences,

IR Windows dialog

The windows dialog now allows a set of window presets to be defined. Presets are created with a Save settings as preset button on the dialog and applied by selecting them from the presets panel.

IR Window presets

The impulse overlay graph has gained fractional octave filter controls to allow all selected impulse responses to be filtered at once. It also has a "Remove IR delay" button which estimates IR delay and shifts the IR to remove it for all selected measurements.

All SPL graph and its tools

There are a few additions in the All SPL graph control set:

Spectrogram and Waterfall

Generation of waterfalls has ben made faster on system with multiple processor cores. There are also a few new features in the spectrogram and waterfall graphs:

The Airy CWT and Morlet CWT modes are Java implementations of a continuous wavelet transform using the algorithm described in Arts, L., & van den Broek, E. (2022). The fast continuous wavelet transformation (fCWT) for real-time, high-quality, noise-resistant time–frequency analysis. Nat Comput Sci, 2(1), 47–58. https://doi.org/10.1038/s43588-021-00183-z

The Morlet wavelet is commonly used for CWT, though it has some deficiencies at high time resolutions, producing artefacts which are a consequence of it being only approximately analytic. The Airy wavelet is from the γ = 3 family of the generalised Morse wavelets. It is exactly analytic and has better performance than the Morlet wavelet at octave fractions from 1/1 to 1/5. At high frequency resolutions, octave fractions from 1/12 to 1/24, the Airy wavelet produces artefacts and the Morlet wavelet is a better choice.

REW's existing Wavelet mode implements the transform using complex smoothing and the time shift properties of the FFT, with a kernel that is less Gaussian (tending more towards triangular) than Morlet or Airy. That gives sharper definition to higher level features of the plot at the expense of more low level artefacts.


RT60 analysis has gained some features, primarily around averaging:


The RTA has a few updates:

Data import and export

There are a number of import/export changes beyond those already mentioned:


The default storage for preferences is system-dependent, in the registry on Windows, for example. With this new release REW can instead use a file for its preferences. There are three ways to configure that:

The -prefs argument is checked first, then the -Drew.preferences.file entry and finally REW looks for rewprefs.txt. Switching to file-based preferences can be done quickly by saving preferences to rewprefs.txt in the log files folder using the new Save preferences to file entry in the Preferences menu and restarting REW. On Windows systems startup is a little faster with file-based preferences.

It is also possible to make REW begin with a particular set of preferences when it starts up. As with the preferences storage file, there are 3 ways to specify an initial set of preferences to use:

The -initialprefs argument is checked first, then the -Drew.initialpreferences.file entry and finally REW looks for initialprefs.txt. If a preferences file has also been specified REW will copy the initial preferences to that file, if not it will create a preferences file and copy the initial preferences into it. The initial preferences file will not be modified.


There are a variety of additions and changes to the user interface:

Bug fixes

Finally, there are a number of bug fixes:

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