Enable mousewheel zoom allows the graph to be zoomed in or out using a mousewheel or trackpad. Limit mousewheel zoom rate prevents the graph from zooming in or out too rapidly. If Show watermark text below on graphs is selected the text in the watermark text box will appear behind all graphs except for the waterfall and spectrogram. Save trace colour with measurement includes the trace colour settings in the measurement file. Use thicker traces for averages uses thicker lines for traces from measurements that are the result of averaging other measurements when plotting them on overlays or in the measurement thumbnail.
Freq axis preset 1 and 2 are buttons that appear on the graph to allow the frequency axis to be quickly changed between the two preset ranges defined here.
The default trace colours can be set up from here, or reset to the REW defaults. The r,g,b values for the trace colour are shown when hovering over the colour buttons. These default colours are remembered for the next time REW starts. Changing the default colours will not alter the trace colours of any measurements already loaded. To change the colours of existing measurements use the trace colour button on the measurement panel or click the Set All Trace Colours To Defaults button on the colour chooser panel.
The text under the toolbar buttons can be hidden by unchecking Show toolbar text labels. The text under the graph buttons can be hidden by unchecking Show graph button text labels. The grid on the measurement thumbnails can be turned off by unchecking Show grid on thumbnails.
Show toolbar controls whether the toolbar appears below the menu, hiding it makes more room for graphs on low resolution screens.
Maximum measurements is the maximum number of measurements that can be loaded in REW. Changes to this value do not take effect until REW is next started. Note that with a high maximum number of measurements REW could run out of memory, if that occurs it is possible to increase the amount of memory REW requests on startup during installation or by editing the roomeqwizard.vmoptions file in the REW program directory using the -Xmx option, REW uses -Xmx1024m by default. Admin privileges are required to change that file: copy it to a user-accessible directory, make the edits, then copy it back using Admin privileges.
General font size is the base font size (in points) for REW. Graph font size is the font size used for the graph axes. Those font size changes do not take effect until REW is next started.
Suppress soundcard errors stops REW showing an error message if it cannot access a soundcard on startup, this may be useful if REW is being used to analyse measurements on a computer without the audio interfaces needed for making measurements.
Use dark background changes the colour scheme from light to dark. Restart REW to update the colours for all components.
Full scale sine rms is 0 dBFS determines whether the rms level of a full scale sine wave is show as 0 dBFS or -3.01 dBFS. If this option is selected the rms level may be greater than 0 dBFS for some signal types, for example, a full scale square wave would have an rms level of +3.01 dBFS.
Show [FDW] in name if used appends [FDW] to the measurement name if a frequency dependent window has been applied.
Distance units selects whether distances are shown in metres or feet and inches.
If Confirm unsaved measurement removal is checked REW will ask for confirmation if you try to remove a measurement that has not been saved since it was last modified. This setting can also be changed from the removal confirmation dialog.
Speed of sound selects the value used for the speed of sound when converting times to distances, calculating modal resonances etc. The default value is 343.0 m/s (approximate speed of sound in dry air at 20 degrees C).
Use macOS file dialogs changes the file selection dialog to a format more like the native macOS file chooser, but note that the macOS chooser does not have the preview panel which REW uses to show the contents of mdat, req, calibration data and image files.
Don't show the welcome message controls whether REW shows a welcome message when it starts up.
Keep SPL Meter on top, Keep VU Meters on top and Keep signal generator on top control whether those windows stay on top of other windows.