Current, state of the art hearing aid chips, actually being tiny, high speed, audio computers, all have ultra-low drain, digital radio transceivers piggybacked right on top. With these, most of the better gear today use their own manufacturers specific, ultra low drain communications protocol to maintain constant real time communications between the instruments on each ear.
However, use of this ultra-low drain, manufacturer specific, communications going on constantly between left and right hearing aids, is currently restricted to being between the hearing aids themselves.
In order to communicate with any of the myriad other smart electronic devices in our lives, such as our smartphones, iPads, laptops, tablets, and such, all hearing aid manufacturers require some sort of an intermediary device.
This intermediary device is used to translate their particular, proprietary protocol into, and out of the widely recognized, industry standard Bluetooth communications protocol, established over twenty years ago, to allow computers and like equipment to securely communicate wirelessly, from short distances. Such devices are referred to as ‘dongles’.
The problem is, that like so many other incredible advances in electronics, computing, and communications, the developers of the Bluetooth protocol were just beginning to visualize the possibilities of the various devices we live with talking to each other.
The power requirements called for to maintain that secure link between the devices originally envisioned twenty some years ago, as measured against the overall power requirements of the gear they were linking, was considered insignificant at the time.
A constant communications drain on the system requiring four, five, or even ten milliamps, was, considered small, and quite conservative by the standards of the day, or even by today’s, if the size of your power source is a laptop, or smartphone battery.
However, the engineers of twenty years ago simply didn’t envision the tiny batteries powering today’s ear level hearing instruments. They all run on batteries tiny by comparison, even to those cells powering those big cellphone dongles you see hanging from so many folks ears.
Laptop, tablet, and smartphones have batteries with ratings in amp hours. Hearing aid batteries have ratings in the milliamp hour range. Hearing aid batteries do a great job powering the equipment they were designed for. In many cases, lasting up to a couple of weeks, running sixteen hours a day.
If, you were to program that same hearing aid to pair, connect, and communicate using the industry standard Bluetooth protocol, the same battery that lasted up to a couple of weeks, would be completely drained, and need replacing every couple of hours.
By the power consumption standards measured in the hearing aid industry, Bluetooth is a huge power hog. Not many hearing aid consumers would stand for changing their batteries every couple of hours.
I have some that complain about having to change them every couple of weeks.
Hence the title of this article, Dangling, Dueling, Dongles refers to the fact that all hearing aid manufacturers to date, require an intermediary device, or dongle.
The dongle is needed to translate between the ultra low drain protocols used for intra-ear communications between the hearing aids, into the current widely recognized commercial protocol we know as Bluetooth.
By using an intermediary dongle, hearing aids are able to establish, and maintain the secure link needed for cell phone calls, the streaming of music, TV, and such without putting a huge power drain on the hearing aid batteries to do so. The job of supplying the bulk of that radio communications energy is shifted to the dongle, which has it’s own, internal, rechargeable, battery, many times the size of the one in the hearing aids.
Today’s hearing aid dongles give between two, and six hours of talktime, and up to several days of paired, connected standby between charges. Charging is accomplished via a transformer with a mini-USB connector, the same one used to program, and mate the dongle with it’s assigned instruments.
Given that today’s high end instruments all maintain realtime, ear to ear communications on a power budget that gets battery life measured in weeks, it isn’t unreasonable to believe that in the near future, consumers will be freed from these dangling dongles. Replacing them will be a manufacturer supplied application suite, downloaded onto, and run by their smartphone, or the tablet that’s communicating with the associated instruments.
The outgoing voice for phone communications, or even application instructions, could easily be captured by the four microphones currently in use, and processed for clarity, even in noise, much like the incoming signal is now, prior to transmission, eliminating one of the current problems with outgoing voice common to most of the dongles in use today.
However, the state of wireless hearing aid communications that goes beyond the ears today, requires a dongle.
They come in two basic types, I’ll call yoked and unyoked.
The yoked devices all require some sort of antenna loop to be worn around the neck and connected to the dongle. The unyoked dongle doesn’t require it’s user to wear it, merely keep it within less than a meter from the instruments in order to maintain communications.
I’ve had experience with both types, from several manufacturers including Oticon, who was first to market with theirs, ReSound, who were about last to market with theirs, Unitron, Widex and Rexton. They all accomplish the same basic tasks, each a little differently. They all have their strengths. some real weaknesses, and not all dongles are created equally, for sure.
As you might guess, having come in contact with so many different dongles, I’ve developed some favorites, and some I’d rather not deal with, but before I discuss that, I’ll spend a little time on each one I’ve used.
Starting with Oticon’s, and to be honest, my experience with this manufacturer is limited to one patient, fit over three years ago who used a cell phone extensively in his work.
Oticon’s dongle has a snap on antenna loop that is neck worn, and attaches to the dongle itself via a plastic clip, which presses the induction coil against the appropriate antenna section built into the body of the dongle.
When it was working, the voice signal from phone calls was clear, and outgoing voice adequate, though the system had some weak spots that made it rather maintenance intensive, when in regular use like this patient put it to.
The design of their neck loop required regular replacement, as it was prone to twisting, fraying and breakage, especially at the clip that attaches it to the body of the dongle. Like other yoke systems, this one is prone to damage by moisture, and being body worn in Florida, sweat is a real problem, even with the rubber over casing available to help mitigate this problem.
Like Oticon, Unitron’s Udirect 2 dongle relies on a yoked system, with an antenna loop that is worn around the neck. I used this system for over a year, and found it generally reliable, with good quality incoming phone, and great stereo streaming of music. Though a yoked system, the antenna loop is more durable than Oticon’s, and plugs in to the top of the dongle from either side.
Unitron’s loop is designed to be a breakaway, in that should you pull on the system one, or both sides of the loop will simply unplug from the body of the dongle without breaking anything. It paired easily and remained so with the devices it was supposed to, and has a nifty voice system that tells you the status of the dongle and spells out incoming phone numbers. The buttons on the front that control it are large and easy to find.
The drawback is like most yoked systems, you’ve got to wear a big piece of electronic jewelry around your neck to get it to work. Where the dongle nestled meant particular care had to be taken when getting a hug, as it was real easy to change change programs, or dial your last cell phone call by being hugged on the wrong button.
Due to being body worn, like the Oticon, the Unitron dongle is prone to moisture damage from sweat and isn’t suited to an active Florida lifestyle as much as it might be.
The other complaint I often got with the Udirect 2, was regarding the outgoing voice signal of the system when talking on the cell phone. Due to microphone placement, and lack of adequate background noise management, outgoing voice was severely compromised in the presence of even moderate background noise, and was often a complaint of the person on the other end of the line.
ReSound’s Alera series uses a non-yoke type dongle that must be within thirty, or so inches of the instruments, to maintain contact with them, but operates like most of the other dongles, up to thirty feet from the cell phone, or other Bluetooth device it’s connected to. When I used this unit, I found that I got good incoming, and acceptable outgoing phone signals with the unit either clipped to my shirt, lapel, or visor.
The operating buttons on ReSound’s dongle aren’t as intuitive, or big as others, making it a bit harder to operate. But, the biggest complaint I had with this system is that it wouldn’t stay paired. It required regular trips back into the control panel, and settings on my Droid, and multiple tries to get it to pair, only to have to do it the next day all over again. This definitely affected my recommendations regarding the system.
However, my experience with the ReSound system is about three years old now, and they may very well have solved this issue by this time.
For ease of use, it is hard to beat Widex’s dongle. With it’s three and a half inch square, full color LCD screen, it looks more like a cellphone than a dongle. The LCD display shows what program, or feature is being accessed, and the quality of the voice, and music stream with the Widex system is suburb.
Being unyoked, it is supposed to operate anywhere within thirty inches of the hearing aids. However, I found that to be a generous distance, often losing the right channel, when streaming music, while wearing the dongle in my shirt pocket.
Like other models, outgoing voice for the phone relies on microphones on the dongle. This can be an issue if the unit is being worn in your pocket, or hung by it’s lanyard inside your clothes. Also, the big LCD screen Widex sports, makes theirs one of the largest, and heaviest of dongles out. So, it’s weight, and size have to be taken into account when recommending it.
The MiniBlu RCU, as Rexton calls their dongle is one of the smallest, and most compact of the unyoked type. I am currently using this model, mated to a pair of Strata 2c 18s and paired with my Motorola Droid and iPad. The small buttons on this unit make it a little harder to operate than the Udirect 2 I was used to.
But, it’s smaller size, weight, and the fact that I don’t have to wear it around my neck, more than make up for having to get used to smaller buttons. And, to be fair they do flash blue with a phone call, which helps.
But, what differentiated the Mini Blu RCU, from the Udirect 2 that I had been using most, was the overall quality of the sound. Not only are the Strata 2cs quieter, and more natural sounding than the Moxis they replaced, the quality of the music streamed through the Stratas, and the Mini Blu are remarkably superior.
As to phone performance, incoming calls are cleaner, and clearer than anything to date, and I’ve already had several folks on the other end of my cell calls comment on the improved quality of my voice. I’ve also found that I am able to use my cellphone in a much noisier environment than before, without compromising what my caller hears on the other end.
Taken together with the performance of their associated hearing aids, I’d have to give top honors in dongles for ease of use to Widex, and best overall to Rexton.
The state of far field communications, and hearing aids today still calls for the dangling dongle.
But, that doesn’t stop me from dreaming of the day when the engineers deploy that direct communications application that will eliminate the need. When they do, it will allow us to begin to unlock more of the full potential that lies so far trapped, within these incredible communications devices we still think of, as hearing aids.