I bought Oticon More miniRITE-R hearing aids two years ago. The problem I have always experienced with these hearing aids is hearing sounds that did not give me any additional value for speech recognition. In noisy, social situations, some people, women in particular, were painful to hear, and I thought that Spanish women had very strange voices! It turns out that the hearing aids are generating frequencies that are not real. This became apparent when I listened to slow passages of music, particularly violin or flute, and there were ānotesā that I knew were not being played. I decided to use a signal generator on my phone to produce pure sine waves, which on the āMyMusicā setting sound like clean sine waves. On every other HA setting there are several frequencies that are simply not real. After many visits to my audiologist with no improvement, she is at a loss to know what to change now. I recorded the sounds my HAs are making with a pure sine wave input, which she played to the Oticon technician in Madrid, and was told āItās something to do with the compressionā ā Not very helpful! Has anyone else experienced these non-existent frequencies with Oticon More miniRITE hearing aids?
Upgrading the More firmware to 1.4.3 fixed a similar problem for my More1 aids.
I understand a widely used technique to reduce feedback at higher gain settings involves actually shifting frequencies a tiny bit. This would cause pure tones to sound different, especially if you also get a bit of live sound through a mold vent or dome vent.
The āmusicā setting disables this frequencies shift. Iām a musician, and the āpureā tones from my microwave and washer/dryer sound distorted in this way when my Phonaks are in automatic. Iām guessing frequencies shift is also disabled while streaming music because i donāt notice it then.
Iām a user, not a manufacturer, so this potentially is wrong.
The frequency shift by 10 Hz is one of the 3 feedback strategies (beside phase change and gain reduction) invariably used by almost all HA mfgs. But since the OPN S, Oticon has come out with a new feedback technology (called the MoreSound Optimizer) that is supposed to replace the traditional feedback management, and this new feedback technology does not use frequency shifting anymore. However, Oticon left the old feedback management in (called Feedback Shield) and allows it to be used in conjunction with the MoreSound Optimizer for the cases where folks have heavy hearing loss and the Optimizer is not sufficient but the combination of the Optimizer and the Feedback Shield would be sufficient to control feedback.
So the first question to the OP is which feedback management technology his HCP has turned on for him, the new one or both the new and the old? If the old one is used, try to turn it off to see if it helps.
The OP doesnāt show his audiogram in his profile avatar so itās not clear if the Frequency Lowering technology (called Speech Rescue) is used or not. If yes, then thatās another potential source of frequency transposition where the frequency is lowered into a lower/more audible region to help with high frequencies audibility. So if Speech Rescue is used, then the OP needs to decide whether this is worth having or not in lieu of having deliberate frequency artifacts added to the sound field for better audibility in favor of better speech understanding.
I donāt think that compression really makes any changes to the frequencies of sounds. It only compresses the gain of the sounds according to how loud the volume of the incoming sound it, depending on the personās hearing loss at each of the frequencies.
Thanks Fred. My current firmware is 1.4.0 so Iāll ask my audi to update them to see if that helps
Thanks for the reply, Volusiano. I thought that speech rescue might have been turned on but my audi assures me that it was not. I did read Oticonās white paper on Speech Rescue, which says that frequencies below 4kHz are never shifted down. The false frequencies are generated very strongly when the real input frequency is between 700Hz and 1100Hz. I downloaded a trial version of a frequency analyser so I could see what the false frequencies are. With an input of 890Hz, the analyser shows only that frequency and the weaker, first harmonic at 1980Hz.
With the HAs, the peak frequency is at 633Hz (louder than 890Hz). Other peaks are at about:- 240Hz, 1260Hz, 1500Hz, 2150Hz, and 2350Hz.
Iāll discuss with her what Optimizer/feedback technology my hearing aids are using. Thanks