I found that it’s handy to have a Tone Generator app to realize when one’s HA ain’t working right.
For a couple weeks, my left Quattro HA rechargeable battery has been draining noticeably less than my right. Used to be the reverse, with less of a difference.
Seemed like the sounds heard from the left mic were somewhat fainter. I noticed the left HA booted normally but within a minute or two, the clarity of a voice heard through the left HA only faded away. (right HA turned off in phone app)
Tests with a tone generator at various frequencies showed that tones streamed to both HA’s were heard ~equally well across a range of frequencies from 100 Hz through 8 kHz. However, if I used the tone generator with wired over-the-ear headphones, although the right HA behaved normally, the left HA had no frequency response above 1.7 kHz or so.
I inspected the microphone openings with a high-powered, high quality binocular dissecting microscope and couldn’t see anything unusual in the openings - same for my audi using her magnifying video otoscope. I did notice that the window on the underside of the HA through which the device serial number is viewed is quite a bit “fogged” or frosted on the inside - not so for the right HA, which has a rather clear window. Might be someone overzealous with the coating material in the manufacture of the left HA.
My audi found the problem par for the course - I think she said something like “problems with microphones, receivers, and wires are not unusual for HA’s” and just said that she was going to send my left Quattro back to ReSound with the recommendation that it’s internal parts be replaced. When I had my mold impressions made, there was a considerable amount of residual liquid in my ear canals that she didn’t remove on completing my impressions and the domes of both HA’s were very moist when I pulled the HA’s out at the end of the day - but she didn’t think any left-over liquid could have worked its way back into the HA bodies (and I didn’t see a sign of anything in the wires of either HA under a dissecting microscope at 12x). The other possibility for me destroying an HA might be sweating at the gym while wearing over-the-ear headphones or wearing gun muffs over HA’s to blot out gym noise while streaming. It’ll be interesting to see if ReSound offers a verdict of “defective HA” vs. something like “user-induced moisture damage.”
So for anyone like me with approximately equal hearing loss in both ears, if one HA starts draining its battery a lot faster than the other, you might find frequency response tests with a tone generator helpful in finding out whether improper reception, amplification, or output of tones at various frequencies is the reason that one HA is consuming noticeably less battery than the other. Gently rubbing my fingers together by each ear, where I couldn’t hear the high frequency “whfffft” sound of my index finger nail being snapped across the inside of my thumb when testing the left HA, was the first clue to having a relative frequency reproduction problem.