The acid test of a good induction loop has to be the user experience. The audio through the loop should have more clarity, the background noise should be significantly lower and above all more intelligible than the same audio picked up by the hearing aid microphone. Where this is achieved, the user can relax, enjoy, understand and participate.
To give some assurance that an induction loop system will provide this positive experience,all systems must be designed, installed and certified in accordance with the international standard IEC60118-4:2006. (see our Knowledge centre Wiki) But even when this is the case, there are still no guarantees.
The standard does not set any intelligibility level. (Garbage in, garbage out) All to often, the installer will opt for using an omni directional boundary microphone mounted on the ceiling. This will pick up all the background noise and feed it into the loop. So instead of listening via the hearing aid microphone to the coctail of backgrouind noise and wanted speech, the user can switch the hearing aid to the T- position and listen to exactly the same thing on the loop. Depending on his hearing aid, he is probably worse off. Digital hearing aids often have steerable microphones and digital filtering programmes which will be bypassed when switched to T.
So in answering your question, A good induction loop system is one that is designed, installed, and commissioned to the standard. Is fed via appropriate microphone types correctly positioned. (Microphones as close to the speaker as possible are best, making radio microphones the ideal choice for most applications). Is checked regularly by staff, using an appropriate loop listener, Inspected and maintained annually. Is clearly signed, so users know it exists and where the staff are trained on its operation and purpose.
When all this is done, the user will love the loop. Of course, I should not forget to mention that the T- facility on the hearing aid needs to be set correctly by the audiologists too
