IRIS 3D records and visualises 3D impulse responses of rooms in an intuitive way:

  • Observe the directional distribution of early and late sound energy

  • Identify specific acoustic events in level, time and direction

  • Link the perception of sound to the architectural form

  • Interaction between the 3D ‘IRIS Plot’ and waveform view

Details of the IRIS plot are described here.


IRIS also functions as a very capable mono impulse response measurement system. All non-3D features are available:

  • Non-spatial room acoustic parameters, including sound strength calibration and measurement
  • Speech intelligibility
  • Open plan office measurements (with the optional module)
Room Acoustic Parameters

Room Acoustic Parameters

The room acoustic parameters from ISO 3382-1 and ISO 3382-2 are calculated in octave bands and displayed in chart and table forms:

  • Decay Range (a measure of the signal-to-noise ratio)
  • Reverberation Time (EDT, T20, T30)
  • Linearity of decay curve parameters (ζT20, ζT30, Curvature)
  • Sound Strength (G, GEarly, GLate)
  • Spatial Parameters (LF, LFC and GLL)
  • Clarity (C50, C80, D50, Ts)
  • Stage Parameters (STEarly, STLate)

For more details, see this page.

Speech Intelligibility

IRIS calculates the Speech Transmission Index (STI) according to IEC 60268-16, as well as Useful-to-Detrimental Ratios.

  • Full STI calculated according to the indirect method
  • Three STI metrics are presented: STI Male, STI Female and STIPA (IR)
  • Evaluate STI/U with multiple and speech and noise conditions for a single measurement

Please click here for details.

Open Plan Office Measurements

IRIS can come equipped with a powerful set of tools for Open Plan Office measurements, following ISO 3382-3 and VDI 2569:

  • Spatial decay rate (D2,S)
  • Level of speech at 4 m from the source (Lp,A,S,4m)
  • Distraction distance (rD)
  • Privacy distance (rP)
  • VDI 2569 room acoustics class

These features are available in the Open Plan Office module, an add-on option to base installations of IRIS for versions 1.4 and higher.

Open plan office measurements are described in detail here.

Hardware Kit

Hardware Kit

IRIS is available with a hardware kit, which includes most of the equipment you need to conduct 3D impulse response measurements:

  • Sennheiser AMBEO VR Microphone with an isolated microphone stand clip, basic wind sock and splitter cable with 4x XLR male connectors
  • Shure ANI4IN-XLR 4-channel microphone preamplifier
  • 30 m STP Cat5e microphone array extension cable
  • Dante AVIO 1-channel XLR analog output adapter for source loudspeaker
  • Pelican Storm iM2450 with custom foam cut-out

Please see this page for detailed description of the hardware kit.

Microphone Array Support

IRIS supports three popular first order Ambisonic microphone arrays:

  • Rode NT-SF1
  • Sennheiser AMBEO VR Mic
  • Core Sound TetraMic

Direct B-format input (with an external A-format to B-format converter) is also available.

IRIS is certified for use with the Sennheiser AMBEO VR Mic.

Sennheiser AMBEO Logoline2 Cropped

What people are saying

  • The operation and configuration of IRIS is effortless...

    Sebastià V. Amengual Garí
  • The success of a musical performance depends on the sense of proximity of performer to listener. This sense is mediated largely by the directional properties of the reflected sound field.

    Sir Harold Marshall
  • Marshall Day Software is like having an acoustic laboratory in the palm of your hand.

    Associate Professor Yan Xiang, Tsinghua University