The Hearing Blog has held off on publishing ratings on the ReSound LiNX “Made for iPhone” (MFi) hearing aid due to current drain issues, as unlike the #13-powered Starkey Halo, the original version was released only in their 312-powered x61 RIC platform.
October 1st Update: The LiNX, Enzo, and UP Smart (pediatric) brocuures and fitting guides are available for download at the bottom of this article. The UP Smart line is the slightly modified LiNX 67, 77, 88, and Enzo aids, with locking battery doors, LED status light, and more colors.
Like the older Verso, the LiNX draws about 2.0 — 2.4mA during normal use; but in our bench testing when receiving Bluetooth 4.0 Low Energy (“BLE”) digital audio the drain jumps to over 6mA, which in our engineering judgment is beyond the capability of the #312 cell due to short battery life and oxygen starvation, especially with Activair & Energizer an cells, including private label cells sold at Radio Shack, Costco & Sam’s. However, the drain figureswe measured are somewhat misleading, as due to the nature of the PWM audio output amplifier, the drain actually spikes above 10mA during loud speech peaks & in noise: This is something you can’t see on a digital drain meter, however those of us who have the older analog meters can watch this. Zinc-air batteries are actually mini fuel cells like those used on spacecraft, but with the oxygen supplied by the atmosphere; and it is these current peaks that cause temporary O2 exhaustion in the tiny #312 cell when the extra 3-4mA drain from UHF reception is in use. What’s more, this exhaustion problem has been exacerbated by the so-called “mercury-free” batteries, which have as much as 20% less energy capacity as well as a higher Thèvenin equivalent source impedance. The high drain coupled with the “new and weaker” cells is a problem our engineer colleagues at Starkey recognized early on, hence their offering their MFi Halo only in a #13 version.
However, ReSound is finally releasing the LiNX in the #13 x77 thin tube BTE & x88 power BTE versions as well as the new “Enzo” #675 Big Boomer that’s on the same platform this coming week, and we await receiving them for bench and real-life testing; and we’ll report accordingly. Worth noting, however, is that ReSound has staunchly refused to release a #13 RIC aid, even though they have had this drain problem since their first-generation Alera was released in 2010.
We also need to remind our readers that out of the Big Six, only Starkey (and Audibel & NuEar), and ReSound (and Beltone & Cochlear) have true MFi hearing aids, i.e. ones that directly support Bluetooth 4.0 Low Energy (BLE). Phonak (and Unitron & Advanced Bionics), Siemens (and Rexton & Miracle Ear), Oticon (and Bernafon), and Widex each use their own proprietary 10.6 mHz digital transmission to get around the drain problem. This is OK for inter-ear coordination and control; but it falls apart because a streamer must be used as a relay between any audio signal and the hearing aids &/or CI’s. What’s more, the lack of a uniform 10.6mHz standard has pretty much reduced those users to using the lowest common denominator for public venue wireless transmission, namely troublesome and expensive baseband induction “hearing” loops via their T-coils.
Brochure and guide downloads:
- LiNX Consumer Brochure (3.2 MB)
- Enzo Consumer Brochure (365 kB)
- Enzo Fitting Guide (675 kB)
- Enzo Data Sheet (340 kB)
- UP Smart Parent Brochure (1.05 MB)
- UP Smart Helping Your Child Learn Languag Guide (465 kB)
- UP Smart Using The Mini Microphone With Your Child Guide (762 kB)
- UP Smart Professional Brochure (2.15 MB)