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Church and H.O.W. Forums for HOW Sound and AV - Your Displayed Name Must Be Your Real Full Name To Post In The Church and HOW Forums => Church Sound => Topic started by: Blake Ross on February 07, 2011, 12:03:00 pm

Title: hearing aid on minister feedback
Post by: Blake Ross on February 07, 2011, 12:03:00 pm
When our minister is using her earpiece mic (AT 892/AT 3000 ) we will get feedback  at times during the service. When we put the same mic unit on others we have no problem.

System is  1 Yorkville U15 flown per side, and the problem does occur when all other mics are muted, and she does not use a monitor.
 
Can someone point me to some reading on the hearing aid/feedback topic? As it is intermittent I'm wondering if it related to the battery level in the hearing aid, or if other factor (s) are making it intermittent.

In the short term I have an appointment with the minister to walk the stage area and notch out the problem frequencies with parametric EQ. Perhaps identifying the problem frequencies will be instructive in itself.

Any help on this topic would be much appreciated!
Title: Re: hearing aid on minister feedback
Post by: Tom Young on February 07, 2011, 01:07:41 pm
When our minister is using her earpiece mic (AT 892/AT 3000 ) we will get feedback  at times during the service. When we put the same mic unit on others we have no problem.

System is  1 Yorkville U15 flown per side, and the problem does occur when all other mics are muted, and she does not use a monitor.
 
Can someone point me to some reading on the hearing aid/feedback topic? As it is intermittent I'm wondering if it related to the battery level in the hearing aid, or if other factor (s) are making it intermittent.

In the short term I have an appointment with the minister to walk the stage area and notch out the problem frequencies with parametric EQ. Perhaps identifying the problem frequencies will be instructive in itself.

Any help on this topic would be much appreciated!

Just to be clear: the feedback occurs with (from) her hearing aids ?

No where else ?
Title: Re: hearing aid on minister feedback
Post by: Blake Ross on February 07, 2011, 02:12:25 pm
Yes Tom, her mic is the only mic on, and the feedback only occurs when the minister is using it. I can put the ministers mic on myself and walk anywhere in the church and not get it to feedback, so I concluded that the hearing aid was the source of the feedback. Of course the church is empty when I am walking around and I never powered up the organ and piano which are nearby to the pulpit.

I do not know if the aid is sending audio from one ear to the other, or is somehow creating a tone that the mic is picking up.

I have heard other people's hearing aids emit a high tone when the batteries are low, but I have not heard this hearing aid do that. Also,  I am not always around for worship and would be too far away to hear that kind of tone anyway.

My hope was that someone had come across an article that explained how the various hearing aids functioned to gain some insight into solving the issue, if the hearing aid is actually the problem.

Thanks for giving this problem some thought!
Title: Re: hearing aid on minister feedback
Post by: Daniel Cash on February 07, 2011, 02:55:06 pm
Yes Tom, her mic is the only mic on, and the feedback only occurs when the minister is using it. I can put the ministers mic on myself and walk anywhere in the church and not get it to feedback, so I concluded that the hearing aid was the source of the feedback. Of course the church is empty when I am walking around and I never powered up the organ and piano which are nearby to the pulpit.

I do not know if the aid is sending audio from one ear to the other, or is somehow creating a tone that the mic is picking up.

I have heard other people's hearing aids emit a high tone when the batteries are low, but I have not heard this hearing aid do that. Also,  I am not always around for worship and would be too far away to hear that kind of tone anyway.

My hope was that someone had come across an article that explained how the various hearing aids functioned to gain some insight into solving the issue, if the hearing aid is actually the problem.

Thanks for giving this problem some thought!

I there there are a lot of additional factors that might be to blame, other than the hearing aid.  Over on the pro side of this forum, they were just talking about how sunglasses and hats can affect gain before feedback in a monitor wedge.  Some monitor engineers carry around a hat to use just for this purpose during sound check.

So with your pastor... earrings, glasses, and open bible or lectern, could all be factors...and it could be the hearing aid.   You should just ask her to turn it off when you do the walk through during the week and see if the feedback still happens.
Title: Re: hearing aid on minister feedback
Post by: Blake Ross on February 07, 2011, 06:52:51 pm
Thanks Daniel, I will report back once I've done the walk around with the minister.

I will try a couple of different mics and transmitters at the same time to see if I can narrow things down.

 We had an issue with another AT transmitter that would stop functioning properly after an hours+ use, which was OK for a church service but very disconcerting when your lead actors mic quit half way through a 2 hour play. :)
Title: Re: hearing aid on minister feedback
Post by: Taylor Phillips on February 07, 2011, 07:16:27 pm
My dad's hearing aids will create feedback when he moves it around in his ear, none of it he hears at all, but we can hear it across the room.  Your minister's mic may be picking up feedback from her hearing aid rather than causing it. 
Title: Re: hearing aid on minister feedback
Post by: Tom Young on February 07, 2011, 08:24:25 pm
My dad's hearing aids will create feedback when he moves it around in his ear, none of it he hears at all, but we can hear it across the room.  Your minister's mic may be picking up feedback from her hearing aid rather than causing it.

That would be my guess, as well.
Title: Re: hearing aid on minister feedback
Post by: Brian Ehlers on February 08, 2011, 01:10:27 pm
If you do determine that the hearing aid is causing the feedback, your next task is to determine if the feedback is:
1/ acoustic coupling within the hearing aid itself.
2/ acoustic coupling between the hearing aid and PA system.
3/ electronic interference (RFI) between the hearing aid and wireless mic.

Regarding the latter, the mic's transmitter could be overloading the circuits (analog or digital) inside the hearing aid, or the digital circuits inside the hearing aid could be causing RFI inside the mic's transmitter (which might be conductively coupled through the mic's cable from earpiece to transmitter).  RFI is funny stuff;  you may find you have a basic incompatibility between the two pieces of equipment.