# Hearing Aid Loop causing problem with our PA.



## micb

Hi,

We put our reliable PA set-up (used many times in various venues without issue) into a town hall here in the UK and all we kept getting was feedback on pretty much everything we plugged in. 

Even when turning off the mixer and amps we got feedback from guitar amps even when just a solo guitar plugged stright in to the guitar amp.

We spoke to the Hall owners and we discovered the hall has a hearing aid loop (inductive) for users who are hard of hearing, so a microphone and seperate inductive amplifer transmits to hearing aids for anyone sitting in the hall loop.

It was late so we could not get any assistance or access to the loop system, so we packed up and came home.

Does anyone have any experience on these loop set-up and how they can interfere with PA set-ups?


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## SinCron

You have to disable the system for the loop as it uses a form of magnetism to transmit to all hearing aids. That affects everything from pickups to microphones.


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## micb

Yes, it seems that is the answer from everyone I have spoken to you have to turn them off.

I'll have to watch out for them in the future.


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## soundman85

WOW, I have never heard of magnetically induced personal listening devices. That seems really inefficient from an electrical standpoint. wouldn't that take way more power than radio transmission? Anyway, sorry to hear about your gig, that would have taken me forever to figure out.


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## hearingspecialist

FWIW, Hearing Aid users switch their devices over to their dedicated Tele-Coil program which picks up the signal thru induction. A hard wired/loop setup provides hearing-impaired patients the very best in their listening experience without limits of the hearing aid directly. :nerd:


In almost 20 years, I have dispensed over 10,000 hearing aids. Man, where did the time go???:huh:


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## gearforears

If the room is looped, this is not a problem—just switch to your hearing aids to their telecoils and you ... One was hooked into the room's public address system and the other was hooked into my portable loop system.


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## micb

gearforears said:


> If the room is looped, this is not a problem—just switch to your hearing aids to their telecoils and you ... One was hooked into the room's public address system and the other was hooked into my portable loop system.


No I don't think you understand.

I was setting up a PA Rig for a band and the inductive loop system made it impossible to use *any* guitar, preamp, mixer or amplifer together as all we got was feedback though the PA speakers.

I was hoping more people with experience with using these loop systems and a seperate PA at the same time could help me with more information.

We had no access to the inductive loop controls as they were locked away.


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## planetnine

Coming to this a little late, but I've never had that magnitude of problem with induction loops. I had a DI box years ago that got a bit sensitive to them, and the odd bass guitar pickup or mic that has picked it up if the conditions are just right (wrong).

I would suggest a quick check of the mains extension leads with your PA, just in case one is letting you run your rig without an earth (ground connection). It might be that the audio gain or the loop drive gain (or both) are set very high in there, or it may be that the piece of kit susceptable to it happens to be the item common to all of it -the console!

It is very disorientating when you get induction loop issues; it's any audible sound that gets fed back into the equipment and it can take a while to realise how it's actually happening. My dodgy DI box was a very good "pit canary" for these situations, and for certain types of publically funded/run building it was worth giving it a listen to if something was behaving oddly. You can't even go looking for the source mic and wrap it up as the bass frequencies always get through.

Was this a gig or a practice your lost?

>


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## KAYCEE

Better late than never.
Had the same problem in our church- put in the induction loop, and it got picked up by the sound system- big time! Gets picked up by single coil p'ups, unshielded wire and all kinds of other stuff. Controlling the receiving end is impossible, so we worked on the source- we added a 50 ms delay in the loop feed, which is undetectable by the receivers, but was far enough from the house sound it doesn't feedback. We still get some interference with the video projector, when the projector bulb is getting weak. Any comments on that?
Cheers
KAYCEE


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