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CMR3 Calibrated measuring receiver for audio analysers

The Ampetronic CMR3 calibrated hearing loop measuring receiver for audio analysers is designed for measuring the performance of audio induction loop systems. The audio output is within ±0.25 dB over the frequency range and where used with a suitable audio analyser such as the Minilyser from Neutrik Ltd, the frequency response and field distribution of the magnetic field from any audio induction loop system can be plotted.

Calibrated to provide 0dBu output for a field strength of 400mA/m RMS, in accordance with the international induction loop Standard IEC60118-4 it is an essential tool for anyone wishing to assess loop system performance for analyses or certification.

Applications include

  • Measure loop coverage and spill
  • Assess frequency dependent loss due to metal structures
  • Certification of an induction loop system to IEC60118-4

Product Code:

  • Features
  • Specifications
  • Standards
  • Downloads
    • Enables easy assessment of the system to the international induction loop standard IEC60118-4
    • Accuracy to within 0.5dB
    • 5 year warranty
    • Compatible with most audio analysers
  • Magnetic field response

    400mA/m RMS0dBu audio output (0.775V)
    Field strengthCoil orientation vertical as indicated on unit

    Frequency response

    50Hz to 8kHz±0.25dB
    30Hz and 14kHz-3dB
    A-weighting filterEN61672-1:2003 sound level meter (Switched)

    Gain stability

    Output variation over battery life<0.1dB
    Output variation due to loading<0.1dB
    Output variation over temperature range<0.25dB
    Overall gain variation<0.5dB


    Output typeActive Balanced
    Load impedance>600Ω
    Connector3.5mm stereo jack socket


    Battery2 x AA alkaline
    Battery lifeApproximately 200 hours
    Battery conditionOK when LED illuminated


    Dimensions62 w x 26 d x 112 h (mm)
    Weight84g (excluding batteries)
    Temperature range-10°C to +45°C


    3.5mm stereo plug to XLR plug adaptor cable supplied (1.5m length), audio cables for simple interfacing of audio devices to loop systems available seperately (see product SCC)


  • The CMR3 is CE marked to all relevant safety and EMC standards

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