IRIS 3D Acoustic Impulse Response
IRIS Software Hedgehog display
3D Acoustic Impulse Response - Measurement & Visualization

IRIS is a powerful and user friendly measurement system for capturing and analysing room impulse responses in 3D.

Download:  IRIS Demo Software & Auckland Hall Example Project

The IRIS demo software allows the review of IRIS measurements.  Please unzip the download.  Install the software (setup.exe) and copy the Example Project to your system. Start IRIS and open the project.  For a quick pick and review of the IRIS assessment features please watch the Youtube Video.

Youtube:     Link

The IRIS Plot

The IRIS plot is at the heart of the IRIS system. Sound rays arriving at the measurement position are represented as a series of easy to identify coloured spikes, immediately after the measurement is conducted.

The IRIS plot can be used to relate sound rays to physical features of the room, observe the directional distribution of early and late sound energy, as well as identify surfaces causing problematic reflections.
It’s simple to understand:

  • the spike direction tells you where the ray has come from (rotation and elevation angle)
  • the spike length tells you the strength of the ray (dB level relative to the initial incoming sound ray level)
  • the spike colour tells you when the reflected sound arrived at the microphone (see color coding based on assessment - Music, Speach,..)
3D Impulse Response Capture & Analysis

The IRIS measurement system utilizes a compact tetrahedral microphone array – a Core Sound TetraMic – which is placed at the desired receiver position. The room is excited by a loudspeaker at the source position, driven with a single swept sine stimulus. The IRIS software provides the stimulus, records the room’s response and processes and visualises the results immediately.

Custom adapter boxes have been designed to simplify the measurement system and a single Ethernet cable is used to transfer the microphone signals. 

IRIS accurately captures how the room’s surfaces direct sound to the receiver position in 3-dimensions.  The 3D image plot displays the measurement via the easy-to-use interface. The graphical nature of the IRIS plot allows for efficient visual comparison of the acoustical properties at different seats within a room, or between different rooms.  IRIS is an excellent problem solving tool allowing a room’s acoustic anomalies to be easily identified. For example IRIS can be used to identify late reflections, or to identify seats lacking in early or lateral energy.  The effect of specific reflective or absorptive surfaces within the room can be identified.


The IRIS kit is shipped in a Pelican Storm case with custom foam.  The weight of the case is approximately 20 lb.  The IRIS kit containing the following:

  • IRIS software on a USB drive and a HASP USB dongle
  • Core Sound TetraMic and microphone stand clip (standard 5/8” 27 TPI thread)
  • TetraMic cable (female-to-female)
  • MOTU 4pre (USB Interface) and accessories
  • CBM box (attached to back of MOTU)
  • PPA box
  • Microphone stand holster for PPA box
  • 30 meter STP CAT5e cable with Ethercon connectors

Additional equipment required for the system and provided by the user

  • Laptop
  • Microphone stand
  • Source loudspeaker with cabling – the output from IRIS is balanced line level via TRS socket.
  • Any necessary power extension cables and power strips.
  • Electrical insulation tape or gaffer tape
  • Headphones