For today’s post, we're going to look at how to do a basic hearing loop system check, to make sure it's functioning properly.
Check for Error Lights
The first step is to check the front of the loop driver and look for any red lights, error lights, or any other warning signs that would signify there might be an issue with the system.
If there is something wrong, then contact your installer and let them know what the error message says.
Check Your Manual
This post is going to focus mostly on the Ampetronic D Series model, in this case, a D10-2, although all the D series operate the same. Most hearing loop drivers are going to operate fairly similar to this but do check your manual to make sure that you're looking at information specific to your model. You can find many different hearing loop driver manuals on our website here: Loop Driver Manuals
The next thing to try is a simple reboot. Just shut the power off, wait about 10 seconds, and turn it back on, usually it takes about eight seconds or so to fully boot up, but this depends on what model driver you're working with. It'll boot up and it should go through some self-checks to see if everything is connected correctly. Then hopefully just a green light pops on and you're in good shape.
If it doesn't boot up, the first thing to check is the fuses. Check to see if it's blown a fuse for some reason. There's a compartment in the back where you can check the fuse and some drivers have a replacement fuse in it you can switch out. When you boot it up again watch it very carefully and make sure that the boot-up goes fine during that process. Or does it cut out of power right away, and you blew another fuse? If that happens, it signifies a more serious issue. If you have an issue like that, where it's blowing fuses, you definitely need to call a pro to check it out.
Play Music or Talk Through The AV System
If it does boot, the next step is to play some music through it or have someone talk into the system. Once you get your hearing loop turned on and playing music through it, then grab one of your loop receivers (if you need one, you can get it in our shop), and turn it on.
Hold the Loop Listener Vertical at Seated Head Height
(About 4' high)
The key with this is to make sure you hold it about four feet high, at least that's the most common setting for a hearing loop because that's about seated head height. It’s also important to hold the loop listener vertically for the best reception. You can sometimes pick up an okay signal with other angles, but vertical is best.
Always Use the Same Volume Setting
The ideal way to listen to a hearing loop and to check with a loop receiver in the basic check is to set a “known volume”. Set the loop listener to a volume that's always the same, that way you can get a really good idea of when it sounds off. By always using the same volume setting you will be able to detect when something sounds too low or too loud.
Listen for Distortion
One of the things you can listen for is distortion. With a hearing loop, distortion is generally going to start in the high frequencies and work its way down because high frequencies take the most power in many hearing loops. However, this does depend on the system design and what you are listening to. If you do hear distortion, try switching the sound source because we want to confirm that it's from the hearing loop and not just from that sound source. Try a few different sources, and if it's still there, also try listening through the speaker system with that same source. If you can still hear the distortion through the speakers, there is a good chance the distortion is coming from something before it gets to the hearing loop.
Turn Off the Loop Driver and Listen for Humming
The next thing you can do is turn off the hearing loop driver completely and listen for humming. Many times there's some background humming in rooms and this is normal but we want to make sure it's not in excess. Note, this humming is primarily at 60 Hz and its harmonics in the US but would be at 50 Hz in Europe. It's a good idea to get an idea of what the humming is in your room. It will vary throughout the room. So, walk throughout the room, again, holding the receiver vertical, and listen to the different sound levels of the humming. If there is humming, how loud is it? What does it sound like? Is it louder in some spots than others? Note all this and keep if any areas are particularly bad, inform users not to sit there.
Hearing Aids Don’t Hear Humming the Same
Now be aware when it comes to the humming that hearing aids and loop receivers are going to sound different. This has to do with how much they drop off the low frequencies. Some hearing aids might drop off the low frequencies a lot, some not as much. It's also going to depend on what kind of humming you have. So if a person with hearing aids is complaining about humming, they can always ask their hearing care professional to turn down some of those low frequencies for their telecoil/hearing loop mode. If you have a loop receiver, many times you can press a button or flip a switch on it, that will cut out some more of those low-frequency sounds and eliminate some of the humming. If you have a pair of loop buds (check out our shop to purchase) there's a hum filter within the app. Go into the advanced settings and then select to turn on the hum filter.
Check for Acceptable Level Variation
If you've gotten this far and the humming isn't too bad, the driver boots up okay, everything's working fine, the next thing to do is check for level variations. This is where it's going to be very important that you have a really good sense of what your volume level is on your receiver, that “known volume” we discussed above. Hold the loop listener vertically at seated head height (about 4’) and walk throughout the room. Then listen and see what those volume changes are like for the sound source you are listening to. Are there little changes or are there big swings? That's part of the international standard for hearing loops is t