Oticon Opn S - Improved feedback management and more gain - #AAAConf19



Hahaha - Suddenly T-coil connectivity is cool again! Because it’s no sweat to add it once you have inductive charging hearing aids.

1 Like


Yeah it’s really for inductive charging, but they might as well use the same coil to pick up the inductive sound as well.



I don’t believe this marketing guy who is obviously not an engineer.
The good old telecoil is a system coming from the hearing aid’s stone age and is integrated mostly due to tender requirements in different countries and not because this coil offers a cool feature. I expect such a coil causing trouble in 2.4GHz systems (interference with the 1.6kHz data package transmission rate in telecoil program).
A telecoil is optimized to fulfil these tender requirements (which are still quite strict) and the coil’s orientation, the material and electrical data is definitively not suitable for a Li-Ion charging.
I believe - looking at the OPN inductive charger concept - that a torrroid coil is integrated in the charger and that the coil antenna of the 10.6MHz radio system (beside 2.6GHz this is still necessary for streaming functionality and binaural sync) is used to close the magnetical loop for a good charging performance of a Li-Ion battery.
I would like to hear a technical explanation from an engineer and not the prattle of marketing people,
Sorry, I don’t want to blame him, but IMHO it is technically incorrect what he says.



The way I read/understood the T-Coil/inductive charging combination is that they both make the hearing aids bigger (which is a comprise) and that is why some recent hearing aid models were not including T-Coils. But since inductive charging already provides the thingamajigger that activates the T-coil then it is very little effort to add T-coil to HAs that are inductive charging HAs.

Though, I could be wrong.



Don Schum is not just a marketing guy, he’s an Oticon VP of Audiology with a PhD. Sure, he may not be an engineer, but I see no reason for him to fudge this Tcoil thing.

To me, as an electrical engineer with an MSEE myself, it’s very easy to see why Oticon would and could have used the same coil they use for the induction charging and turn it into a double duty design to function as the Tcoil for audio loop as well. It would be very dumb of them not to take advantage of using the same induction coil for charging to use as a Tcoil as well.

Of course Oticon is not adding the Tcoil functionality on the rechargeable OPN S out of the goodness of their heart. They only added it because it’s a no-brainer to add it in since the coil is already needed there for induction charging.

Or you can also see it the other way. They already wanted to add the Tcoil in, so they figured they might as well make induction charging out of it, too.

Either way, it’s a clever ploy to kill two birds with one stone.



Hi – thanks for the response. I am based in Europe so I don’t know this VP of Audiology who was interviewed here. Even he holds a PhD he must not necessarily have a deeper knowledge about the fundamental principles of inductive charging.
Probably his telecoil-charging story is much more convenient to understand for everyone and in the end it doesn’t really matter to the customer. If they are satisfied with the performance of their rechargeable system, everything is ok. So I agree.

Anyway - telling me something technically very strange and probably incorrect, this is not what I appreciate. A simple telecoil in a hearing aid would be (caused by its electro magnetical characteristics) one of the most inefficient components in a contactless rechargeable system. Oticon developers are aware of this for sure.

There is a patent published (see link) which describes a concept of a magnetic loop charger for hearing aids under the condition these devices are equipped with a coil-antenna of a 10.6MHz based near field communication system, this coil with its high permeability should do the charging task much better than any telecoil:

(this patent’s application is an inductive rechargeable hearing aid).
Schematics to get a clear picture:
schematics from patent application

The OPNs offer such a 10.6MHz coil-antenna which is intentionally foreseen to be used for the streamer. So the OPN devices have in principle everything for such a technically sophisticated and efficient charging solution already on board! Also here: one coil with two functions or one stone kills two birds…

Are there really any technology based arguments from engineers to make me believe the telecoil-inductive-charging story? I’m OPN to listen and would like to get technically founded opinions about the telecoil to be used to pick up the energy for a charger system instead of the 10.6MHz antenna. It is fun to reflect marketing prattling from an engineering perspective, but as I’ve said – finally no customer will care about this if the system works for him as expected.

If someone likes to do some patent research: In principle all the industry’s creativity and knowledge is published as a patent with the purpose to protect it and to earn fees. And I am curious…

I apologize for my niggling, I must not always be right and I can imagine that a purely technically focused discussion goes off-topic quite fast. Probably this aspect of inductive charging how it is described in the patent and the fact that it is very unlikely to use a telecoil for inductive charging - this may be of interest anyway in some cases?

Let’s OPN one of these chargers to see which primary coil is built in and if it fits the secondary one, the hearing aids’ antenna! :slight_smile:



If you’re arguing that Oticon must have used 2 different coils, one for inductive charging and a different one for Tcoil function, I’m not going to argue with that because I don’t really know how they implement it anyway, and like you said, users don’t really care, as long as they get to have both, they’re happy anyway.



The stones come from the stone age and are still used for many things, some very cool. One of the cool uses of T-coils is the possibility in a large place to send audio wirelessly from a single transmitter to multiple receivers at the same time just pushing a button, without configuration and in a minimum space inside hearing aids.
From your engineer point of view @seb_m What current wireless communication system is capable of doing this? Other common systems in hearing aids such as FM and Bluetooth do not allow it.

1 Like


@Volusiano Simply opening up the devices will clarify this :wink:
The inductive charging method is not a secret, this will be obvious then.
Unfortunately I don‘t own an OPN-S R system (yet - I‘ll wait some time, because IMHO it is not wise to buy freshly released technical products but I would like to go away from the batteries). Since I know how to dis- and re-assemble my OPN1 312-T, it should be possible too to open up the rechargeable device in the same way. A pity if the charger housing is glued and can‘t be repaired.
@tenoch yes, stones are rock solid! True. But sometimes stones are often not compatible with newer technologies when new materials in connection with these stones are required:
The inductive pick up of signals in the audible frequency range with a traditional coil will pick up also all the dirt from your 2.4GHz system, so the engineers have to implement some restrictions in the tcoil program.
The induction of unwanted noise into a tcoil will become more and more a problem in our electro magnetic contaminated environment. I bet without the still existing regulatory requirements the hearing aid industry would love to get rid if that coil and offer something new, even the user benefit is not the same. Anyway, there are two most important things which counts for the manufacturers: It’s the the ‚induction‘ of hearing aid sales and market share. Who‘s surprised? :slight_smile:

1 Like


@seb_m One of the fundamentals in audiology and communication is that a poor signal is better than no signal. You can get something minimally significant, even a little, from a bad signal but you can not extract something from nothing.
e.g. Cinema -just an inductive loop around the room and everyone gets the sound from the movie. Churchs, elevators, theaters. Anywhere where there may be many people with hearing needs.

The regulations about t-coils exist because today, after decades and decades of research, engineers have not created a wireless transmission system for hearing aids, thinking about the needs of the hard-of-hearing people, as simple, effective and universal as the t-coil, that allows an emitter connects to multiple receivers at the same time without the need of installations with advanced technical requirements, without complex configurations. The day that this system becomes reality and suitable for hearing aids, the regulation will stop forcing the t-coil and force the new system.

I can assure you that everyone in the industry is looking forward to a modern, low power, extremely small, universal, direct, multiple and simultaneous connections wireless communication technology become reality. But until that moment arrives, “ancient & poor” sound of t-coils is much better than nothing. :slightly_smiling_face:

1 Like


New Oticon S on order and this morning I changed them to the T coil version. A little bit bigger than the non T Coil but I don’t think bigger than the OPN 1 I wear currently…and it has the dual rocker switch which I am accustomed to currently. Ny audi just got back from an Oticon training system and while I won’t know until I actually try them, he seemed confident we will have better results than what I am experiencing with the OPN 1’s I currently have.