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3D-Distortion Measurement (DIS)

This module performs a series of steady-state measurements by using a single- or two-tone excitation signal varied in frequency and voltage. Two signals may be measured simultaneously (e.g. current, voltage, displacement, SPL). Due to high quality converters and synchronous data acquisition, the spectral components (fundamental, harmonic and intermodulation distortions, DC part) can be obtained with high signal to noise ratio up to 48 kHz signal frequency. After performing the measurement (voltage and frequency sweep), the magnitude of the spectral components is displayed in a 3D or 2D plot versus voltage and frequency of the excitation tone.

The 3D-Distortion Measurement (DIS) provides features especially valuable for transducer measurements. The transducer can be protected against mechanical and thermal overload by pausing the measurement automatically if the total harmonic distortion or the increase of the voice coil temperature violates user defined limits. 

  • Optimal for measurements of transducers and audio systems
  • Considers mechanical, electrical, acoustical signals
  • Measures voice coil temperature
  • Visualizes amplitude compression
  • Detects critical speaker distortion
  • Assesses maximal output
  • Thermal and mechanical protection
  • Adjusts voltage at speaker terminals
  • Detects amplifier gain automatically


DIS Standard

provides all standard measurements according to IEC 60268-5.


provides amplitude modulation distortion in addition to the functionality of the DIS Standard.

The figure illustrates the measurement of the maximal SPL level at a defined THD limit (1, 5 and 10 percent) using DIS measurement and MAT 2.0 post-processing module. The DIS module varies the amplitude of the stimulus and protects the transducer under test against mechanical and thermal overload. The MAT 2.0 module extracts the measurement results of the DIS automatically and calculates the corresponding SPL limits. There is an object template available for this application in dB-Lab called “Max SPL Level for given THD.

Templates coming with the SIM module:

DIS 3D Harmonics AN 9

Harmonic distortions versus frequency and voltage according Application Note AN 9

DIS 3D Intermodulation AN8

Intermodulation distortions versus frequency and voltage according Application Note AN 8

DIS Compliance Asymmetry AN 15

Checking for asymmetries caused by compliance according Application Note AN 15

DIS Compression Out(in)

Output amplitude versus input amplitude at four frequencies

DIS Harmonics vs. Voltage

Harmonic distortion measurement versus amplitude


Weighted harmonic distortion (blat distortion) used for Application Note AN 7

DIS IM Dist. (bass sweep)

Intermodulation distortion in current and sound pressure using a variable bass tone fs/4 < f1 < 4fs and a fixed voice tone f2 >> fs

DIS IM Dist. (voice sweep)

Intermodulation distortion in current and sound pressure by using a fixed bass tone f2 < fs and a variable voice tone f1>> fs

DIS Motor stability

Checking motor stability at frequency 1.5 fs (where Xdc is maximal) according Application Note AN 14

DIS SPL, Harm protected

Harmonic distortion measurement with protection

DIS X Fundamental, DC

Fundamental and DC component of displacement

DIS Separation AM Distortion

Amplitude modulation distortion according Application Note AN 10

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