Overlays Window

Overlays Window

The overlays window shows plots for all the currently loaded measurements. It is shown by pressing the Overlays button in the toolbar of the main REW window.
Overlays button

The overlay plots are selected via the buttons at the top of the graph area.

Overlay Graph Selector

The various graph types are:

All the measurement SPL traces
Predicted SPL
The predicted SPL for each measurement after applying any EQ filters that have been defined for the measurement in the EQ Window.
All the measurement phase traces
Predicted Phase
The predicted phase for each measurement after applying any EQ filters that have been defined for the measurement in the EQ Window
Distortion traces for each measurement, showing the distortion measure selected in the graph controls, which can be IMD, TD+N, THD, THD+N, N, any available harmonic up to the 10th or the fundamental. If a mix of stepped level and other measurements are loaded either the stepped level or the others will be selectable for the overlay. The easiest method is to right click on the graph legend and clear the selections, then select one of the measurements of the type you want to overlay. Only other measurements of that type will then be enabled for selection. Clearing all the selections will mean all measurements become enabled for selection.
All the measurement impulse responses. There are a a set of filter controls matching those on the Filtered IR graph providing a quick way to filter a set of impulse responses.
All the measurement impulse response envelope traces
All the measurement step responses
All the measurement group delay traces
All the measurement RT60 traces, with options to show an average of the selected traces and to export the average values
All the measurement clarity/definition traces

Separate Traces

The basic controls for the overlay graphs are described in the main Graph Panel help, but the Overlays window has one additional button:
Separate Traces Button

The Separate Traces button to the right of the graph selector offsets each trace downwards from the preceding trace to make it easier to distinguish individual features when the traces are at similar levels. When the button has been pressed a slider next to it allows the amount of separation to be adjusted.
Separate Traces Slider


Actions Button
The Actions button brings up a menu of actions for the currently selected graph type. All overlay graphs have these actions:

SPL Overlay actions

The SPL overlay graph has an action to apply an SPL offset to an individual measurement. The SPL offset moves the graph position, but does not alter the data so the legend values do not change. If the Add offset to data button is pressed the current offset value is transferred to the measurement data and the legend readings will update accordingly.

The SPL, Predicted SPL, Phase, Predicted Phase and Group Delay overlays have actions to apply smoothing to all the currently selected traces.

The SPL overlay has an action to export all the selected measurements as text.

The Phase and Predicted Phase overlays have additional actions to wrap or unwrap the currently selected phase traces.

The Impulse overlay has actions to set the t=0 position, undo t=0 changes, remove IR delays, export as text and export as WAV.

The RT60 overlay has actions to export the average of the selected measurements and an action to export the RT60 data for all the selected measurements.

Graph Controls

SPL Overlay controls

The SPL, Phase, Impulse, Step and Group Delay overlays have a Show points when zoomed in control. If selected the individual points that make up the measured responses are shown when the zoom level is high enough for them to be distinguished (which may only be over part of the plot).

The SPL and Predicted SPL overlays have an IEC 263 ratio control which allows the graph to be locked to a specified dB/decade aspect ratio. The aspect ratio is maintained by adjusting the margins around the graph as required.

The Impulse overlay has controls to filter the selected measurements.

All overlay graphs have a Trace options button which brings up a dialog that allows the line type of the graph traces to be changed.

Legend area

Right clicking in the legend area of an overlay graph brings up a small menu that allows all traces to be selected, all selections to be cleared or the selections to be toggled. There are also menus to select or clear traces for measurements that have been loaded from a particular file. A range of traces may be selected by holding the shift key while clicking the selection box for the start of the range then clicking the box for the end of the range.

Overlay Legend Popup

Individual measurements can be disabled by right clicking on the measurement's thumbnail. The currently selected measurement can be disabled using the Ctrl+D shortcut. Disabled measurements cannot be selected, are skipped when using the next/previous measurement shortcuts (Alt+up/down and Ctrl+up/down) and are not shown in the legends of overlay graphs. All measurements can be re-enabled via an entry in the right-click menu of the graph legend or by using the Ctrl+E shortcut. All selected or all unselected measurements can be disabled via the entries in the right-click menu of the overlay graph legend.

Hovering the cursor over the name of a measurement in the legend panel will bring up a tool tip showing the measurement notes. It will also highlight the measurement on the graph. When a measurement is selected it will automatically be highlighted, the highlight for the currently selected measurement can be toggled using the Ctrl+H shortcut.

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