Guest Article: Does Chromecast Signal a Bad Week for Bluetooth? [And How This Applies to Us]

[Updated 10/20/2015] Today’s Guest Article is on 2.45 gHz streaming audio by 802.11 WiFi as well as 802.15.4 Bluetooth 4.0 Low Energy (“BLE”), and the various ways both protocols coexist side-by-side both for audio streaming and control. This has major implications for hearing aids, CI’s, and assistive devices, because except for the dodgy telecoil there is not quite yet a universal broadcast standard for hearing devices; so as software-driven Digital “Moore’s Law” radios are just around the corner — and Sonova announcing them this week for delivery next year — hearing impaired people will finally have crystal-clear digital audio streamed to our hearing aids & CI’s with inexpensive universal broadcast transmitters in theaters, houses of worship, and stadiums; and in noisy vehicles such as taxis, airplanes, and subways.

Editor’s Note: From time to time The Hearing Blog presents interesting guest articles for our Readers. Today’s post is the twelfth in our Guest Article series, written by Paul Williamson, who is general manager of the wireless business unit at low power chip specialist ARM. This article originally appeared in the ARM Connected Community blog, where it originally appeared. [Edited 10/20/2015 to also repair broken links]

Related coverage:

Chromecast-Hi-ResThis week Google launched their new Chromecast audio and encouraged you to switch to WiFi for your streaming audio. The shift in audio listening habits is real, content is no longer local, and streaming is growing at a huge rate.
So does this mean the end for Bluetooth Audio?

The outlook in home listening is bleak for Bluetooth Audio. With competition in streaming audio services we are being reintroduced to audio quality.  Services such as Tidal HiFi and Deezer Elite are driving Lossless and higher fidelity codecs.  This is likely to drive a shift from Bluetooth toward WiFi as the primary streaming source at least in the home.

It is not the end of Bluetooth in this category. It is likely that many players will keep a Bluetooth link. The applications will likely shift to setup and configuration. Bluetooth low energy in particular enables simple discovery and app based control. It will be easier to enable others to discover the player and connect using Bluetooth low energy as shown in the new B&W Zeppelin Wireless, which uses an iPhone app for setup. There is also a need for a local remote, and as the recent 4th generation Apple TV teardown shows Bluetooth low energy is a great technology for this application.

Personal audio

The outlook for Bluetooth in personal audio is still strong, but quality has become a challenge that the standard must address. As consumers grow to expect HD audio capability in their streamed content the high-end wireless headphones must also meet the challenge. A number of proprietary codec extensions to Bluetooth streaming standards have emerged, such as aptX (owned by Qualcomm) or Sony LDAC, which offer improved fidelity of the audio content.

Editor’s Note: Two additional codecs are used in hearing aids & CI’s, in Phonak’s Roger system, and in GN ReSound’s Unite system, including by licensee Cochlear2   Both of these codecs have low latency as a vitally important feature to minimize feedforward comb filter distortion 3 which starts at 10 mSec latency, and echo, which starts at 40 mSec delay, which is the delay by the above-mentioned aptX codec, as revealed in this aptX Low Latency demo video.5 Although 40 mSec latency is about the limit for maintaining lipreading cue synchrony, this is inadequate for hearing aid use, as many hearing aids are “open fit” with thin tube BTE or RIC, and use open dome eartips so that ambient low frequency sound is heard.

There is one further segment where Bluetooth may evolve to meet consumer needs. Recent kickstarter innovations have shown the potential for the reinvention of the Bluetooth headset. Projects like Dash, Dot and Ear-in show a drive for more compact low power wireless earbuds. The success of the projects shows the interest in ditching the wires on the ubiquitous earbud, but the current standard and technology weren’t built with this product in mind, and there will be some serious Engineering work to get these products to the mainstream.

So Bluetooth is facing some challenges. It is being pushed to deliver new audio capabilities of lower power and lower cost at one end while meeting higher quality at the other. The outlook for Bluetooth is still strong, and perhaps in the area that is least visible – Connect and Control. In the Smartphone Bluetooth low energy maintains a unique position offering simple user experience for setup and control, and this could be the reason that means that Bluetooth is deployed in ever more products.

Paul_Williamson_ARM_Cambridge_UKAbout the Author

Paul Williamson is general manager of the wireless business unit at ARM. ARM processors are the brains in billions of devices, and now ARM Cordio IP provides the latest low power connectivity to devices. ARM Cordio offers complete fully qualified Bluetooth low energy IP to enable the rapid development of connected devices.


  1. As we understand it, the HIMSA initiative to provide a universal programming protocol involves 10.6 mHz;
  2. GN ReSound and Cochlear Limited Establish Smart Hearing Alliance to Develop and Commercialize Bimodal Solutions;
  3. feedforward comb filter frequency response

    Typical feedforward comb filter frequency response. Click to enlarge

    We use the more accurate “feedforward comb filter effect” terminology to differentiate it from the less commonly encountered “feedback comb filter effect” – Here is a graph of the feedforward comb filter frequency response. Also, below is a brief audio demonstration of the feedforward comb filtering effect:

  4. Back on April 1st we published Three new technologies from AB, Phonak and Med-El, where what started as a spoof from Valencia was answered by us:

    Of the three technologies introduced today, we are especially excited about the next-generation Naida speech processor containing a commodity dual-function Bluetooth and WiFi chip, which is standard in mobile phones and tablets — And it’s about time, as Williams Sound already has WiFi sound distribution with their Hearing Hotspot system. What’s more, the hardware hooks for Bluetooth have been in place since 2005 when the Harmony was released, using the coil wire as a 2.45gHz antenna.

    Then, on April 5th, we added the following:

    Although this was our 2015 April Fools’ prank post; in fact the first item on 2.45gHz WiFi connectivity for remote CI Mapping & hearing aid programming, as well as WiFi audio distribution, is much closer to reality than our readers may realize, as the main barriers seem not to be so much technical as the slow-motion pace of CI & hearing aid development; and once these developments roll off the production line, getting the sclerotic audiology community to actually use these new technologies in their dispensing (can anyone say “Real Ear Measurement?!)

    In Any Event, as we have pointed out several times, the issue with digital audio distribution to hearing aids & CI’s is twofold: For 2.45gHz UHF it’s one of radio power drain, which will soon be addressed with the Digital Moore’s Law Radio once we get production volume semiconductor manufacturing down to the 14-15nM λ die shrink; and alternately a lack of universal 10.6mHz CODEC standards between Siemens (which pushed for them), Widex (which is off into their own coordinate system), Sonova (Phonak, Unitron, AB, & Hansaton), and Demant (Oticon, Bernafon, Sonic and Neurelec/Oticon Medical).

    Will we see WiFi in hearing aids & CI’s anytime soon? Both 802.11 WiFi and 802.15 Bluetooth are two-way frequency-hopping protocols, as are the Phonak Roger and ReSound/Cochlear Unite systems based on Bluetooth 4.0 Low Energy (“BLE”), which means the antennas are already in place in devices that support these protocols. However, 802.11 WiFi tends to draw more power due to the typically longer ranges involved, so look for it to be deployed first on multicell CI processors and 675-fueled hearing aids; then once we get down below the 11nM λ die shrink to the 7-8nM range, we may see it in #13-powered devices.

    Put succinctly: The first item on our 2015 April Fools’ post can, in fact be done today

  5. [Added 10/20/2015] Here is the aptX Low Latency demonstration video. Unfortunately, Damien has a thick accent and is hard to understand, and irritatingly even though it appears he read from a script, the video is not captioned:


← Sonova's 2.4 gHz Digital "Moore's Law" Bluetooth Radios to Debut in 2016 Two New Articles On Atraumatic CI Electrode Insertion And Residual Hearing Preservation →

About the author

Dan Schwartz

Electrical Engineer, via Georgia Tech


  1. Robert Thompson
    October 18, 2015 at 1:55 am

    Like the article Dan. I didn’t know you went to Georgia Tech.

    I’m looking forward to the day when developers (which are increasing in number for future decades) and those familiar with DSP (whether through audio software via product or via library; Supercollider for Android and iOS, and other specific to iOS only) — I’m looking forward to when we can “hook” into a very specific part of the hearing aids and allow some of us to customize our solutions further.

    More and more hardware components are available via RPi 2 and other Linux variant related systems such as OpenWRT.

    ~ Robert

    • Dan Schwartz
      October 18, 2015 at 3:12 am

      The issue is one of latency: Software DSP solutions take too long to process sound, leading to feedforward comb filter distortion starting at about 10 mSec — That is why you don’t want more than about 16 channels in a hearing aid, as otherwise the “buckets” become too large, leading to latencies.

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