Iris eng

IRIS is a measurement system with software and hardware for measuring  the 3D impulse response in  rooms and evaluation of reverberation time and other room acoustical parameters.

IRIS is a powerful and user friendly measurement system for capturing and analysing room impulse responses in 3D. Beside measuring standard room acoustic parameters (ISO 3382) IRIS allows to analyse room reflections, theirs direction and theirs intensity.

Visual output

  • 3D colour-coded representation of sound rays
  • Length indicates relative sound intensity level, angle is the ray direction, and colour represents time of arrival
  • Separate music and speech arrival time categories
  • Interactive 3D rotation and zoom
  • Dynamic range and time resolution adjustment
  • Specific angle and level information for individual rays for detailed analysis
  • Broadband and octave band filtered view

The window is divided into four main areas:

  1. List of measurements
  2. Measurement details and a summary of the results
  3. Detailed results
    • IRIS 3D PLOT shows the IRIS PLOT (only available with a 3D receiver).
    • PARAMETERS lists the various room acoustic parameters from ISO 3382-1 and 2.
    • SPEECH contains speech specific parameters including STI.
  4. Waveform view – the time domain impulse response signal in a linear or log form.

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

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.

Impulse Response

  • Traditional omnidirectional waveform views
  • Dynamic interaction between the IRIS plot and waveform view – rays selected in one view are highlighted in the other view
  • Automatic detection of onset time with manual adjustment

3D Impulse Response Capture
The IRIS measurement system utilises a compact tetrahedral microphone array 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.

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.

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.

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)

Compact Hardware Kit

  • IRIS is an affordable software and hardware 3D impulse response measurement system
  • The system consists of:
    • IRIS Software and USB dongle
    • Ambisonic microphone
    • Shure ANI4IN-XLR 4-channel microphone preamplifier
    • Dante AVIO 1-channel XLR analog output adapter for source loudspeaker
    • 30 metre CAT5E STP microphone array extension cable
    • Pelican Storm case with custom foam cut-out

More information on the IRIS website www.iris.co.nz

and https://docs.iris.co.nz/v2/