NTi Audio
Impedance Meter

Impedance Testing of 70 V / 100 V Systems

Solutions for impedance testing:

Minirator MR-PRO Impedance Detail

Flexus FX100 Audio Analyzer

MR-PRO Audio Generator

 FX100 Audio Analysator

Impedance Testing with the MR-PRO Audio Generator

The Minirator MR-PRO measures the impedance and power rating of distributed speaker systems. Deviations from the expected result identify problems such as bad connections, incorrect tap connections or short circuits. Use the optional 70 V / 100 V Protection Adapter for safe operation.

The impedance test supports the verification of distributed loudspeaker installations and shows detailed information of the connected load. The test result shows if the connected speaker system is in good order as well as the required amplifier power ratio. The power is automatically calculated by the measured impedance for 25 V, 35 V, 50 V, 70.7 V, 100 V, 140 V, 200 V systems.

      Minirator MR-PRO Impedance Detail       Minirator MR-PRO Power
                    Impedance and Phase                                    Apparent Power and Phase

Detecting Installation Problems

The Minirator MR-PRO helps to detect problems, such as
  • Speakers not connected
  • Speakers wrongly connected
  • Connection to wrong transformer taping, e.g. 1 W instead of 2 W
  • Short circuits
  • Other external products, such as fire alarm devices connected
  • Bad connection cable

Advantage of MR-PRO Measurement Technology

Vibration and environment noise within the area of the speaker commonly effects the speaker impedance measurement results of other test instruments. The MR-PRO impedance measurement includes technology for achieving stable readings within noisy environments.

Measurement Hints

  • Disconnect the 100 V amplifier from the distributed speaker system prior any measurements.
  • The typical test frequency is 1 kHz.

70 V / 100 V Protective Adapter for MR-PRO

70V/100V Protective Adapter for MR-PRO Protects the Minirator MR-PRO against accidentally applied voltages during impedance or power testing at distributed 70 V / 100 V speaker systems.

NTi Audio #: 600 000 313

Product Data

Order information


Exel Impedance Meter Kit

  • Minirator MR-PRO
  • 70 V / 100 V Protective Adapter
  • Mains Power Adapter
  • Exel System Case

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Impedance Testing with the FX100 Audio Analyzer

The FX100 Audio Analyzer, together with the 100 V RT-IB Impedance Test Box, allows to acquire the impedance response of virtually all loudspeaker types, including distributed audio 70 V / 100 V loudspeaker systems.

The tests are executed with a logarithmically swept Glide-Sweep. This technology ensures very fast, yet precise measurement results.

  • For loudspeakers up to 30 kΩ nominal impedance
  • Selectable shunt resistor: 10 Ω, 20 Ω or 400 Ω
  • Impedance response
  • Resonance frequency
  • Impedance at resonance frequency

Example of a 100 V loudspeaker impedance response:


RT-IB Impedance Box
The 100 V RT-IB Impedance Box is tailored for the impedance response and resonance frequency testing of 70 V / 100 V speakers.

NTi Audio #: 600 010 395

Product Data

Order Information


Flexus FX100 Audio Analyzer

FX100 Base Unit

Flexus FX100 Audio Analyzer (2 Channel)
including FX-Control Suite Software.

NTi Audio #: 600060000

Get more Information

Buy at the web shop or contact NTI Americas .

Minirator MR-PRO

Contact NTi Audio

NTI Americas Inc.
Tigard, Oregon
Thomas E. Mintner
+1 503 684 7050

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