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IRIS Plot Overview

IRIS provides an intuitive and interactive visualisation of the 3D impulse response data in the form of an IRIS Plot. An example is shown below.


This plot illustrates sound energy arriving to the receiver (the origin of the plot) as a series of rays or vectors, where the length of each ray indicates level, the angle is the incoming direction, and colour corresponds to time of arrival since the direct sound.

IRIS plots can be useful for:

  • Visualising the relationship between the architecture of a space and how it sounds.
  • Comparing the acoustical features of a space at different positions (or comparing different rooms).
  • Observing the directional distribution of early and late sound energy. For example, seeing how laterally distributed the early reflections are.
  • Identifying acoustic anomalies, such as a surface causing a disturbing echo.


Please carefully review the following sections before making any judgements from IRIS plots. At one level these diagrams are very intuitive, but you should also understand their limitations.