Sonova made a Big Splash here at The Hearing Blog, introducing the first 2.4 gHz all-digital “Moore’s Law” 802.15.4 Bluetooth Low Energy 4.0 and 802.11 b/g/n WiFi radio chip, debuting in 2016… And we are quite pleased, as this will pave the way for standards-based 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.
- Guest Article: Does Chromecast signal a bad week for Bluetooth? [And How This Applies to Us]
- Sonova Panned By Stock Analysts Over Lack Of 2.4gHz Digital Connectivity In Venture Platform, Costco Backlash
- 16/14 and 10nM Semiconductors Enabling 2.45gHz Digital “Moore’s Law” Bluetooth Radios For Hearing Aids & CI’s
- Digital “Moore’s Law” Radio: The Enabling Technology For “Made For Apple” Hearing Aids
This week Sonova held their annual Investor & Analyst Day in Stäfa, lifting their skirt on their roadmap for the coming year; and unlike last year which was a bust (and for which we took them to the woodshed), this year they came through… And in a Big Way, with what appears to be an industry-first all-digital “Moore’s Law” 2.4 gHz radio chipset, to which we first introduced our readers three years ago, and updated in June as the 16/14 and 10 nM semiconductor die shrink node was introduced, which at 16/14 nM is the crossover point where all-digital radios draw less power than analog radios; and 10 nM will probably draw about 30% less than that. We cannot stress how important this development is for the hearing impaired community, as we are just on the edge of universal all-digital transmission standards.
How this will all play out remains to be seen: As Paul Williamson, who is who is general manager of the wireless business unit at low power chip specialist ARM, explains here, we may see a hybrid Bluetooth/WiFi implementation where the connection & control is over Bluetooth and the streaming is over WiFi. However, with all-digital “software” radios, this is not an issue, because as experience is gained in the field, it’s no more difficult to reconfigure the radio than simply clicking “Update now” on your iPhone.
Here are the three wireless roadmap slides from the presentation: Click on any of them to enlarge in a new window.
State Of The Headworn 2.4 gHz Digital Streaming Market:
This will bring to four the number of manufacturers which have headworn hearing devices that directly support Bluetooth 4 LE (“BLE”); but each has quirks the patient and clinician should review. As of this writing in October 2015:
- GN ReSound and their troubled Beltone division produce the LiNX² and new Enzo² hearing aids, which support direct BLE as well as their similar “Unite” protocol for wireless streaming and control accessories;
- GN licensee Cochlear produces the BAHA BP-500 which supports direct BLE as well as their similar “Unite” protocol for wireless streaming and control accessories, and the CP910 & CP920 “Nucleus 6” CI processors which support only the Unite accessories except for the remote control, which is handled by a dedicated “Remote Assistant;”
- Starkey, whose Halo only supports BLE and lacks compatible wireless accessories;
- Sonova, which currently produces the Roger FM system and purpose-built FM receivers.
Besides streaming remote audio, radio plays important audiologic & control functions in hearing aids & CI’s, and here is where the tradeoffs between 2.4 gHz UHF and 10.6 mHz HF (sometimes called “near field magnetic induction” or “NFMI”) come into play, especially related to battery drain, because with any digital RF signal but especially UHF, as the data rate goes up, so does the power drain. From lowest to highest bandwidths & hence drain, we have the following functions:
- Inter-ear user control for volume and program shifts;
- Inter-ear automatic program shifting, such as Phonak’s Sound Flow;
- Inter-ear compression coördination, to preserve spatial cues — But there is no clinical proof this improves speech perception in noise;
- Inter-ear microphone beamforming coördination, i.e. beam steering;
- Inter-ear audio transmission for networked microphone directionality (Phonak Stereo Zoom and Siemens Binax); and also for CROS 1 (and BiCROS, 2 and Deluxe CROS & BiCROS3). While the other uses listed above involve a low data rate and will work at 2.4 gHz (λ = ⅛m = 5″) with the signal crossing the lossy dielectric in the skull without draining the battery, when you get up to the datarates needed to send even compressed audio the drain gets out of hand, hence the need for 10.6 mHz ISM band digital transmission. What we may end up seeing, at least in CI’s and premium hearing aids, is dual band 10.6 mHz & 2.4 gHz Bluetooth — Sonova already has a de facto version of this when you hitch a purpose-built Roger receiver onto a Phonak aid now;
- Wireless programming: Depending on whether the hearing aid microphone audio is transmitted back to the PC’s transceiver, and the distance between the devices & transceiver, this can be a trouble spot for 10A and even 312-fueled devices.
What we don’t know yet on Sonova’s new Digital Moore’s Law radio are three key technical details:
- Will these radio chips be built at the λ = 14/16nM step; or due to the small chip area and “premium” use will early 10nM λ chips be procured?
- Will 802.11 b/g/n WiFi be supported as well as 802.15.4 Bluetooth 4 Low Energy?
- Will this be a single band 2.4 gHz radio, or will it support dual band 10.6m/2.4gHz operation?
- CROS = Contralateral Routing of Offside Signals, for a dead ear and a normal hearing ear to compensate for the head shadow effect; where sound is transmitted from the dead ear to the good ear, almost through an open earmold to prevent loss of sound;
- BiCROS = Binaural-Contralateral Routing of Offside Signals, for a dead ear and an impaired ear
- Deluxe CROS & BiCROS: These are “oldies but goodies” from the hearing aid dispenser’s bag of tricks: Basically, these are used when the bad ear is unaidable due to poor speech scores, but it’s desirable to put sound into it anyway to preserve binaural directionality. The way these work is to aid the bad ear and also transmit the audio to the better ear, where it’s either mixed with ambient audio with an open fit earpiece if the hearing is normal (Deluxe CROS) or mixed with audio from the hearing aid and then fed into the better (but impaired) ear (Deluxe BiCROS). Fitting these patients is more of an art than a science, as it involves trying to identify just exactly what the patient perceives in their almost-dead ear. Here’s a hint: Try to determine the degree of dys-synchrony in the bad ear, as the worse the neural firing synchronization, the more distracting the perceived audio will become. Listen to this sequence of profound, severe, moderate, mild, and then no ANSD (AN/AD) samples created at Kresge and vetted with several unilateral ANSD patients (you’ll get an alert to play or save the .MP3 file).