Termination and Commissioning of Induction Loop Systems

After the installation of an induction loop, be it a multiloop or a fixed counter loop system, proper termination is required and followed by commissioning of the system with the AV System as a whole before handing over to the end users.

Proper termination of cables from the induction loop system is crucial to ensure that the induction loop system as a whole, is functioning correctly and is performing optimally.

These factors are crucial for proper termination;

1. Ensuring loop medium is correctly routed and secured, minimizing the risk of damages or interference.
2. Making precise connections between loop medium and amplifier which may include soldering or using dedicated connectors to the amplifier.
3. Verifying the integrity of the connections by conducting tests to ensure proper signal continuity of the induction loop system.
4. Proper grounding of induction loop system to prevent unwanted interference.

Commissioning of induction loop systems is the final stage of the installation process, where the system’s functionality and performance are tested.

Tests that will be done during the Commissioning of the induction loop system would include checking of Signal/Field Strength, Frequency Response and uniform coverage of the induction loop system.

1. Background Noise Test – To ensure that the Magnetic background noise generated by other equipment like a generator or mains wiring does not affect the performance of the induction loop system.
   1. Readings should not be higher than -32dB.

2. Signal/Field Strength Test – To determine the system’s output level, ensuring that it complies with the IEC 60118-4 Standards so that hearing aid and cochlear implant users would have a comfortable experience.
   1. For parameter loops and multiloops systems, readings should be between ±3dB.
   2. For counter loops, readings should be ±6dB to comply with the IEC 60118-4 standards.
      1. If it does not meet passing requirements, adjustments on the amplifier have to be made until it achieves passing results.

3. Frequency Response – To assess the system’s ability to reproduce audio frequencies that are clear and audible. This is where Metal Loss Compensation in the amplifier plays a huge role to compensate for the cancellation of loop signal to a certain degree due to Metal Loss.
   1. Results should be showing a Flat Frequency Response reading as much as possible for both the High and Low Frequencies of 100Hz and 5kHz respectively.
   2. Optimal results would be in the range of ±3dB of 1kHz for both frequencies.

4. Signal/Field Strength Test – To re-test the system’s output signal after adjusting the Metal Loss Control to overcome the Metal Loss.
   1. For perimeter loops and multiloop systems, readings should be between ±3dB to comply with IEC 60118-4 standards.
   2. For counter loops systems, readings should be ±6dB to comply with the IEC 60118-4 standards.

5. Live Test – To ensure that the current settings applied on the amplifier is within the comfortable listening range and still within the IEC 60118-4 Standards when an audio source is playing either via Line Input or Microphone.
   1. Readings should be between -6dB and +3dB for counter loop systems and Multiloop systems.

6. Uniform Coverage of induction loop system – To ensure that there is a consistent signal quality, clarity and no “humming noise” throughout the coverage area.

Fine-tuning of the system amplifier would be required to optimize the performance as per end user requirements and also to meet and comply to the IEC 60118-4 Standards.

Once the commissioning process is completed, a Certificate Of Confirmation will be issued as a form of verification that the induction loop system is ready for use.