Test Solution for Room Acoustics

Reverberation Time RT60

The Exel Room Acoustics Kit measures the behavior of acoustic sound in enclosed spaces, such as dwellings, class rooms, auditoriums, offices, theatres, concert halls or transportation terminals. The kit consists of the DS3 Dodecahedron Speaker set and the XL2 Acoustic Analyzer. All measurements are performed in accordance with the relevant standards.

At a glance

  • Optimizing open plan offices (ISO 3382 or ASTM E1374)
  • Standardized reporting
  • Compliant with ASTM E2235


Room acoustics describes how acoustic sound behaves in an enclosed space. Typical room acoustic measurements are

The acoustic response of the room should fit the primary purpose of the room. For example, for good speech intelligibility in classrooms, a reverberation time RT60 of less than a second is desirable. In a concert hall designed for orchestral music, a reverberation time RT60 of 2-3 seconds may offer a rich and warm sound experience. Based on measurements, the acoustic properties of an enclosed space can be modified e.g. by redesigning the room or adding soundproofing materials to walls or ceilings.

Sound Source

Room acoustic measurements require a sound source with a diffuse sound field, which means that the sound energy has to be distributed uniformly. For this reason a sound source with an omnidirectional radiation characteristic is best used for precise measurements.



DS3 Dodecahedron Speaker Set

The DS3 Dodecahedron Speaker is a powerful sound source with omnidirectional radiation characteristics. It consists of 12 loudspeakers of the same type, mounted to a dodecahedron-shaped chassis. The optimized frequency spectrum delivers a high level of equalized sound energy for precise reverberation time measurements. The DS3 is powered by the portable Power Amplifier PA3, which offers a built-in pink noise generator with an equalized output signal. The wireless remote control allows the test signal to be switched on/off from outside of the measurement room.

Minirator MR-PRO

Minirator MR-PRO

The Minirator MR-PRO generates a gated Pink Noise with a low crest factor dedicated to RT60 measurements. In addition, the MR-PRO offers the Speech Intelligibility signal and a GlideSweep signal with editable cycle time. All test signals may be replayed via the DS3 Dodecahedron Speaker set.

Reverberation Time RT60

The XL2 Acoustic Analyzer measures the energy decay in the range from 63 Hz to 8 kHz by the Schroeder method in 1/1 octave bands. Automatic triggering and averaging of multiple measurements simplifies the operation and minimizes the measurement time. Use either an impulse source or an interrupted pink noise as the test signal. The optional Extended Acoustic Pack extends the RT60 measurement to a 1/3 octave resolution.

XL2 RT60 Reverberation Time


Speech Intelligibility STI

The XL2 Analyzer, with the STIPA Option installed, measures the speech intelligibility according to the latest revision of standard IEC 60268-16:2011 (edition 4) and older editions. It offers ambient noise correction and automated averaging for repeated measurements. The XL2 displays the speech transmission index (STI) and the common intelligibility scale (CIS), accompanied by the individual levels and modulation indices of the seven octave bands.

XL2 STIPA Analyzer


Relative Sound Pressure Level

The XL2 is a powerful sound level meter for comprehensive room acoustic measurements. It offers a wind range of levels, such as average Leq, maximum or minimum sound pressure level measured in combination with frequency weighting A, C or Z and time weightings fast, slow and optional impulse. All results are simultaneously available.

XL2 Sound Level Meter

Customers may log all acquired level information onto a removable SD card. Additionally the XL2 offers wav-file recording for a complete documentation of the measured sound pressure levels. Voice notes may also be added to each measurement.

Real Time Analyzer RTA

The RTA perfectly suits the sound optimization in rooms. The XL2 measures and logs wideband values and the real time spectrum in 1/1 or 1/3 octave-band resolution according to IEC 61260 class 0. The sound level meter results of the wideband and RTA spectrum are simultaneously available.

XL2 Sound Level Meter

Noise Curves

The XL2 Acoustic Analyzer provides a noise curve measurement for an objective rating of the background noise level in a room. The noise curve rating of a spectrum is designated as the value of the highest noise curve “touched” by the measured octave-band spectrum. The speech interference level (SIL) and the noise curve rating are calculated in parallel. The Noise Curve function is offered with the Spectral Limits Option.

XL2 Noise Curves



Exel Set for RT60 Testing

Exel Kit for Room Acoustics

  • PA3 Power Amplifier
    with built-in noise generator
  • DS3 Dodecahedron Speaker
  • Speaker Stand for DS3
  • XL2 Acoustic Analyzer
  • Extended Acoustic Pack for XL2
  • M2230 Measurement Microphone
  • Minirator MR-PRO
  • ASD Cable for XL2
  • 2x Mains Power Adapter
  • Exel System Case

Optional as required:

Spectral Limits Option for XL2

for noise curve measurements

Precision Calibrator

for user calibrations

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