IRIS 3D Acoustic Impulse Response Gallery

System Schematic

Computer running IRIS drives Motu USB Audio Interface

Interface connects to amplifier/speaker or PA System and TetraMic

Room Under Test

30 second Swept Sine Excitation per Microphone Loc

Data gets processed. The IRIS system visualizes the resulting 3-D impulse response data as a 2-D or 3-D ‘IRIS plot" or "Hedgehog" or Thiell's "Igle"

Impulse Response Time Window

Color Coded Time Periods

0 - 2 ms (red)

15 ms to 50 ms (Green)

50 ms to 200 ms (Blue)

Lateral Energy Fraction LF

Acoustic Parameter:

Early to Late Arrival Energy Ratio ( C80 - dB)

Early Decay Time (EDT)

Reverberation T20, T30

Time of the Centre of Gravity of the Squared Impulse Response (TS - ms)

Early to Total Sound Energy Ratio (D50 - dB)

Peak Signal to Noise Ratio (PSNR - dB)

PPA Box - Mic Amplifier

IRIS Kit

TetraMic & Cable

MOTU 4PRE USB Interface

CBM Attached to MOTU

30 m STP CAT5 Cable