Bluetoooth LE Audio, Hearing Aids, and Mindtree

You might think that hearing aids are a bit of a sleepy backwater. Indeed, the only time I can remember coming across them in my job at Cadence was at a CadenceLIVE Europe presentation that I never blogged about, or if I did, it was such a passing reference that Google cannot find it. But hearing aids have been in the news recently for two separate reasons!

OTC Hearing Aids

The first reason is that the FDA has approved hearing aids for over-the-counter (OTC) sale, meaning you don't need to go to a doctor and get a prescription. Historically, OTC sales take place at much lower prices than prescription-only, for all sorts of reasons that are beyond a Breakfast Bytes post. From the FDA's website:

This action establishes a new category of over-the-counter (OTC) hearing aids, enabling consumers with perceived mild to moderate hearing impairment to purchase hearing aids directly from stores or online retailers without the need for a medical exam, prescription, or a fitting adjustment by an audiologist. 

You might think of hearing aids as those flesh-colored (if you are white) bulky things that hang over the ear with an earpiece. I think they consisted of a microphone and an amplifier, perhaps with a bit of filtering.

But modern hearing aids fit completely in the ear channel. They contain sophisticated digital signal processing and enable people even with severe hearing loss to hear again. Here's a paragraph about someone getting a new hearing aid that I remember reading a few years ago. The author is a retired TV weatherman with 85% hearing loss since he was an infant:

When I got in the hotel, I decided the first thing I should do is celebrate a bit so I went to the bar to have a drink. It was there that I confronted my worst nightmare and my biggest test of whether these would actually help me or not: a tiny little blonde woman who was the bartender. She could not have been more than 5 feet tall.

The World Series game was on the TV and there were a lot of people in the bar and there was a lot of noise, and I dreaded the moment where I was going to have to speak to this tiny little woman because tiny women have tiny voices and tiny voices are often high-pitched and very difficult for me to comprehend. So, my test was on and she spoke to me and a miracle occurred: she asked me what I wanted and I told her I wanted a “Manhattan on the rocks” and then she asked me what kind of Bourbon I wanted it and I was able to say with pride exactly what I wanted. She returned a few minutes later with a drink and then asked me if I wanted to order something to eat and asked me if I wanted to hear the specials for today. For decades I’ve never heard what the specials have been in restaurants – they are just something that I waited for it to be over, but this time I heard them all.

Now you have to understand that this normal mundane everyday event that most of you reading take for granted is something that would strike terror in my psyche every time I have to go through this. But this time something amazing happened, something I hadn’t anticipated. You see, because I couldn’t hear myself I’d always had this booming voice and to some people that booming voice was offputting even though it was great for being a broadcaster. Now, my voice is much lower in volume. And as I described my order to this tiny little blonde woman who was the bartender she leaned over to me and said “can you repeat that”? This was a moment I’ll remember forever. All of a sudden the tables were turned, and I was thrilled beyond imagination to be able to repeat something for someone else. I began to cry and tears were streaming down my face. I was so happy and I couldn’t stop it because the weight and pain of the last 40 years were suddenly lifted from me. It truly was epic.

I'm sure you have seen some of those YouTube videos of kids who have received a cochlear implant when it is first turned on, and they hear for the first time in their life. This sounds just as transformational for someone who has had hearing loss from infancy.

Bluetooth LE Audio

The other thing that happened is that the Bluetooth SIG completed the LE Audio specification in July of this year. The LE Audio spec was actually driven by the hearing aid industry and addressed inadequacies of "Classic Bluetooth":

• Single peer-to-peer audio stream transmission, for TWS, one earpiece needs to ‘relay’ the signal to the second earpiece.
• Monolithic profiles and control protocols – e.g., HFP cannot work with A2DP, which means voice control (HFP) cannot co-exist with music streaming (A2DP)
• Lower power and support for more processing and function
• Lower latency
• High Quality
• Interoperability – mix and match devices from different manufacturers

TWS is "true wireless stereo" and is a feature of the Bluetooth standard that allows two earbuds (or speakers) to synchronize perfectly despite not being connected, with one channel going to each bud (or speaker).

To promote all this audio goodness, Bluetooth has branded the new capabilities Auracast. From the Auracast website:

Auracast broadcast audio is a new Bluetooth capability that will deliver life-changing audio experiences. It will let you share your audio, unmute your world, and hear your best, enhancing the way you engage with others and the world around you. 

This technology is not just targeted at hearing aids, of course. Any application where you want to hear high-quality sound without everyone else hearing too: silent TVs in bars, background music to your life, announcements.

Mindtree and Tensilica HiFi

Tensilica is the leader in audio digital signal processing (DSP) with its HiFi series of DSPs. The latest is HiFi 5, which I covered in my post "Alexa, What Is HiFi 5?" Mindtree is a Bluetooth IP provider and a BT 5 standard contributor. They have over 100 design wins for their IP, including both the controller and PHY, as well as a software stack.

HiFi 1 DSP is the smallest and lowest power member of the HiFi DSP family, is particularly relevant for OTC Hearing Aid, as it was developed for battery-constrained applications.  Besides having a small area to reduce SoC cost the available artificial intelligence (AI) functions with neural network (NN)-specific ISA and architectural features target advanced audio processing use cases. For more details on HiFi 1, see my post Always Listening, HiFi 1 DSP.

With Mindtree and its large software ecosystem, Tensilica HiFi brings fast-to-market, lowest energy Bluetooth LE Audio that solves the need for bringing advanced assistive hearing relief technologies to improve well-being in this new market. The LC3 and LC3+ codecs are fully supported by the HiFi family (along with over 100 other codecs).

Fun with Hearing Aids

I can't believe that this was made in 1979, 43 years ago. For many people, this is the most memorable of all the episodes (just 12) of Fawlty Towers. Even then, electronic power was a problem:

"It's working perfectly alright."
"No it isn't."
"Yes it is, I haven't got it turned on at the moment."
"Why not?"
"The battery runs down."

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