Loop / T-coil to Bluetooth adaptors



I am having trouble with my left first generation Linx and I am a very fussy iphone and high-end user.

So, I am comparing the new Linx (next week) and trying the Halo IQ now. I love the sound of the Halo and fit, but working the app seems to take more time, though there are a lot of options. I’d love the telecoil for the theater, but have never used one.

What’s your sense of the comparison between the latest versions of each. My audi is great, but has few users willing to pay for this technology and/or afraid of it.


I’m an audio engineer not an audiologist so we have people who use our building with a number of different types of HA which we do our utmost to support. I try and keep up to date with the latest technologies which is why I’m very interested in Bluetooth 5 and the Hearing Aid Profile.


I don’t know of a single device. A two stage device might work though with a receiver Adastra LR2 Induction Loop Receiver: Amazon.co.uk: Electronics
connected to BT trasmitter TaoTronics Bluetooth Transmitter, Bluetooth 4.1: Amazon.co.uk: Electronics


That’s really interesting. I did see the Adastra LR2 before when doing some research. I thought I could, as a option, pop an Arduino development board inside with a Bluetooth 4.1 module that has the HFP and do it that way.

The goal would be to have a device the user could slip into a pocket or on a neckloop.

The Taotronics would be great for a proof of concept. I’ll have to look at the specs to see what profiles it has.

Given any unit would be mostly used for speech, I’d have to get the latency down so wouldn’t use the dual connect feature.


I’d be interested to see if you can make that work. Getting the all the various HAs and a BT transmitter to work in low latency mode might be difficult. The only other viable way I see is streaming the audio over wifi to the users HA connected phone, as suggested above.


… and that’s the key. I know that at a base level, our Bluetooth HA wearers can use the HFP protocol. That’s fine as long as the latency is under 40ms, otherwise you get a weird out of sync effect. HFP would be fine if the user was only streaming off a recording and not someone speaking in front of them.

Looking at the proprietary HA streamers, we could have one connected directly to the mixing desk so as long as the users were up 30ft / 10m from it (many to one) then they would get a direct feed. The issue for me is that the streamer would be at the back of a 45ft space (it would be hard to hide halfway up the space), so there is still the latency of the front of house speaker sound reaching them to compensate with.

The streamer approach is fine as long as we only have the same manufacturer of HAs being worn. If we don’t, it’s another £250 each time. We have to watch our budget.

I’m sure there would be a sweet spot in the room so they got the t-coil -> Bluetooth feed and the FOH audio near the same time.

The aptX protocol looks great for latency but I’d be surprised if the HAs would recognise it.

It would be great if I could make the t-coil -> Bluetooth neckloop work. It would be BT Class 4 (30cms / 12 inches) so it wouldn’t interfere / try and pair with other Bluetooth HA wearers around it, plus it would help with the unit’s battery life.

I can’t see t-coil disappearing soon so it would be a worthwhile investment in time.


OK, had a check on the Taotronics and it only uses the AD2P profile.

Say we could connect a generic Bluetooth HFP sender to the mixing desk, I can’t see that working as many HAs would be competing to pair with it, ergo the low power neckloop.


If users have purchased or have been prescribed bluetooth hearing aids (without telecoil), you might expect they would have a compatible phone and be using the app. Streaming an audio feed to their phone seems to be an easy existing solution. If their fitting of hearing aids has been inappropriate, no telecoil or working phone, as there is currently no working universal live audio connectivity for bluetooth hearing aids, maybe they need to seek help from their audiologist.

Good overview of the problem here http://www.hearingloss.org/sites/default/files/Sterkens_MFi_BluetoothandTelecoils-OhMy.pdf


Why don’t you leave it all on the inductive broadcast and suggest that HA wearers use the t-coil setting while offering another headset system that just reads the loop signal for people who are having bother.

That removes the latency issue and offers an alternative.

Even before you get into problems with proprietary signals, you’re going to get Bluetooth pairing issues, as the aids won’t be holding an open Bluetooth channel. That’s for the very small % of aids that can handle standard Bluetooth.

The other option would be to use the user’s phone to handle the Hearing Aid interface and broadcast the signal on a free call number - when the users dial in they can get the commentary for free direct to their aids on their hands free profile. The big advantage of doing it this way is that you’d need minimal hardware at your end other than a dedicated line for the outgoing sound feed and a word with your phone supplier to allow multiple connections.


@Pavane You will likely find that the 3D’s app has more to it also. The Linx did not have all the directionality features that have improved in the last two+ years. You can download the new app and look at it in demo mode.

A poorly informed audiologist will be a hindrance.


Oh that’s an interesting idea (making a phone call). And that would work for that Phonak too.
My previous posts on this topic hinted at streaming from that Phonak. That was wrong. It’ll stream with it’s streamer. And then phone calls in mono.


I am unsure which APP you meant. I am using the Halo TruLink app now, which has more flexibility than the old Linx app, but takes longer to load and use. I went to a noisy restaurant with soft-spoken friends last night and was shocked at how the HAs immediately adjusted to the environment on their own and I could hear everyone at a 4-top table easily. So I assume that is the directionality feature. Looking forward to comparing next week with the Linx.


The issue is only for HA wearers that don’t have a t-coil setting on their HAs. They only have Bluetooth.

True that only a few HAs have full standard Bluetooth functionality. From what I’ve read it s more common for HAs to have say the HFP and HSP profile enabled only to allow them to receive phone calls and act as a headset. This would bypass Apple tweaked Made For iPhone protocol.

Yes, I could ask the Bluetooth HA wearers to remove their HAs and put on a pair of Bluetooth headphones linked to a standard A2DP streamer at the back but I’m trying to keep it discreet.

Costco Kirkland Signature 8.0 (Product Information)

In addition, none of the Bluetooth HA wearers owns a smartphone.


Well then. There goes wifi or a phone call.
An earlier post of mine joked about handing them an iphone though. It doesn’t need to have a SIM for wifi.
That would work for standard bluetooth PSAP’s and made for iphone HA’s


IMHO the task you imagine (supporting ALL hearing aid types) is simply impossible! T-Coil is the only technology that has any chance of being compatible across brands, but many audioligists and manufacturers manage to screw it up so that the person with the hearing aids has no idea how to use it.

You’ve probably already figured this out, but you need to be _very careful when the term “Bluetooth” (perhaps even with a version number) is used in the Hearing Aid context. Often this only means the PHY layer of standard Bluetooth is being used, but the profile is proprietary (controlled by Apple in the case of Made-For-iPhone). The only 100% standard Bluetooth solutions that are available have excessive latency (200ms or more) and so aren’t very well suited to applications where the voice needs to match the mouth (for example TV watching) and also require more power than Hearing Aid battery life expectations can deal with. The newer Bluetooth-Low-Energy (BLE) solves the power problem, but there is no standard profile that supports both audio streaming and control. (Until recently, and perhaps still, there was NO standard BLE profile that could carry streaming audio.)

Further, most Hearing Aid manufacturers conflate communication source<->medallion with communication medallion<->HearingAid. So when they say “Bluetooth”, they probably don’t mean that the Hearing Aids can do Bluetooth directly. What they mean is that the source<->medallion communication is standard Bluetooth, but the medallion<->HearingAid communication is actually something else (most likely Bluetooth-LIKE, which just adds even more to the confusion.)

While everybody says “Bluetooth”, very few hearing aids actually support a 100%-standard Bluetooth solution all the way to the Hearing Aids themselves. And it’s not at all clear that those that do are on the right track with a technology that will persist for more than just a couple of years.

Again in my opinion: it’s very sad that, due mainly to the behavior of the hearing aid manufacturers, it’s simply impossible -even for a supertech familiar with all the specs- to equip a building with any broadcast hearing aid system that will work for most of the hearing aids that come into the building.


I had hoped Bluetooth 5 would solve a lot of these issues, but it seems to gotten really bogged down. I also see talk of a Bluetooth 5.1 coming “soon.”