In fact I would say the KS8’s work exactly the opposite. They reduce background noise when there is no voice activity, and then when voices are detected in the direction the microphones are focused in, then amplification is increased so you can hear them. It would seem difficult to filter out a blower type noise while at the same time amplifying voices. Speech ranges from about 200 Hz to 6,000 Hz. I suspect they depend on the fact that when voice activity is louder than the constant level background noise your hearing system tends to tune out the lower level noise. Switching programs to change microphone focus seems to help with this issue by ignoring voices and sounds that are not in the direction of interest.
Did somebody at Costco officially confirm with you that the Hearlink is based on the faster Velox chip? Or if this is just based on rumors in this forum?
If it’s really based on the faster Velox chip, then it should behave like the OPN S. But based on what’s been described here, it doesn’t sound like that’s how the OPN S behaves.
Yes, the technician at Costco confirmed they use the same chip as in the OPN S, but in an interview I read Demant said the software is different. They indicated that OPN S and Hearlink share the same new anti-feedback software, but the SoundMap noise control and amplification software in the Hearlink Aids are unique to them and the OPN software is unique to Oticon.
The hardware appears to be identical between Philips Hearlink and Oticon OPN S other than case styling. Even the charging station and other accessories are identical other than the brand name.
In case you’re interested, here’s some of the documentation that convinced me to try the Philips Aids, and it describes exactly what I’ve experienced: https://www.hearingsolutions.philips.com/en-us/professionals/product-technology
Yes it would. It detects speech and then directs amplification in that direction just like the KS8s and other brands do.
I think you’re correct: It “…uses an embedded noise level estimator to lower the compression ratio in specific moments and frequency channels. This preserves access to speech cues, and thereby optimizes the access to speech information in noisy conditions.” And “…this combination of speed and accuracy in SoundMap Noise Control enables it to attenuate noise at a pace faster than the speed of speech.”
I’m not sure I understand all of that, but I do think that’s what I’m experiencing.
It is consistent with the official channel from Oticon saying that the new feedback technology in the S is shared in the Hearlink. So it does make sense that the new Velox chip is used in order to make use of this new technology.
Higher comprehension is due to compression system it use nearly liner compression in low frequency in presence of noise. Literature in philips link shows it. And for quiter environment it will adopt non liner.
I need to read that Phillips link again to make sure I understand it as well as possible. However my initial thoughts are that compression is just amplification based on the sound level. Normally there will be three zones of compression and two knee points that separate them. And again normally based on hearing loss vs frequency the compression ratios and knee points change with frequency. And the normal strategy is to amplify lower level sounds more than higher level sounds. This is to try and correct for the non linear hearing loss that most have. Our loss is greater at lower levels than higher levels.
So, when they say they change the compression that is really a back door way of saying they are changing amplification. Again it is pretty normal for the noise reduction logic to do that. Perhaps it means more than that, but that was my conclusion based on the initial read.
I may not get all of this correct but:
You’re correct that compression is amplifying softer sounds more. That’s a simple way of putting it but generally accurate. And once a sound is audible, then that works. So now you have the sounds that used to be in that range. You have to move those medium sounds up too otherwise they would get lost with the soft sounds and sound garbled and completely unnatural. So you amplify those a little bit, but now the louder sounds need a place, so you move them up a little too. The problem is that in an environment with a huge range of sounds of all levels coming from all directions, if you try to be too smart about your amplification, one minute you’re surrounded by soft sounds and the next you’re surrounded by loud sounds. And that is changing every millisecond. So the safest bet (for clear understanding) is to stop worrying about what sounds are soft, what sounds are medium, and what are loud… and to just focus on trying to figure out what you might want to hear and making it stand out as best that you can. The best way to do that has a lot to do with what the hearing loss is, what the surrounding sound that needs to be dealt with is, what the comfort level is, and what sort of isolation the hearing aids can provide due to open domes, tulips, closed domes, power domes, or earmolds. The more closed off the hearing is, the more you can retain that compression and keep a moderate level of comfort. The more open it is, the more it is necessary to compete for any spot to be heard.
That’s why they say they change the compression. In a “quiet” environment, it’s easy. In a busy, loud environment, decisions have to be made by the device on the spot.
Even though I wear closed domes, what you’ve described is exactly what I’ve experienced with all my previous hearing aids (Phonak, Resound, Kirkland), but not with the Philips.
They all amplify the frequencies that match my hearing loss and when I turn them up they all amplify those frequencies even more. Unfortunately, the noise emanating from the air conditioning vents in my living room at home and the conference room at work is in the same frequency range as my most severe loss. So, before I got the Philips, it was almost impossible for me to understand speech when the a/c was on, no matter how much I turned up the volume on them. That was especially true of the KS8s, which amplified the blower sound SO MUCH!! WHOOOSH!! It was bad enough that I would occasionally turn off the HVAC during meetings at work and make everybody sweat or freeze. Good thing I’m so popular there!
Right! And the Philips aids make better decisions. When the blower comes on it’s LOUD, that is, until somebody starts talking. Then the aids detect speech and somehow, almost miraculously, stop amplifying the noise of the blower and only amplify the speech. (Impossible, I know, but it seems like that.) Quoting the documentation: “The noise reduction system further attenuates noise in frequency bands dominated by noise.” So I hear the speech clearly and the noise of the blower is “attenuated.” (They stop amplifying all the white noise frequencies of the blower that don’t exactly match the voice of whoever is speaking.) The end result is that I understand what people are saying much better, the noise of the blower is greatly reduced, and we all get to enjoy the air conditioning.
So when speech stops you hear the blower noise again, but as soon as speech starts and during speech, you don’t get overwhelmed by the blower noise and can hear speech better? But the overall result is that it’s as if the blower sounds is always there, but you can now understand speech better despite the blower sound being as if it’s always present?
Or is the blower noise still greatly reduced in between speech? For example, somebody says something, then stops momentarily, then somebody else chimes in to answer. Is the blower noise still greatly reduced in between that non speech moment?
Good question. I wish it continued to recognize the blower as just noise and leave it subdued, but it does come back during moderate pauses in speech. If the conversation continues as it usually does there’s no problem, but if there’s a couple of seconds pause (I haven’t timed it) the noise does come back.
The rising and falling volume of background noise can be annoying. There’s a lot of room for improvement in the programming. It’s most bothersome when watching a baseball game on TV. The announcers pause often and for lengthy periods as they should, but when they do the noise of the crowd in the background rises too much. I think that’s exacerbated by the television production itself, which also brings up the noise of the crowd when the announcers aren’t talking.
OK, thanks. Initially many people originally speculated that the Hearlink was a cousin of the OPN. However, there was official confirmation later that it doesn’t have the equivalent of the OpenSound Navigator. Your explanation above confirms this, because with the OpenSound Navigator, it would have sounded like the blower noise never left, so there’s no rise and fall in the noise volume in between speech. Nevertheless, that noise is still reduced in the presence of speech, just too quickly for you to realize that it was reduced, only for you to notice that you can understand speech better.
The Hearlink noise reduction as you described seems more consistent with the experience I had with the Sonic Enchant 100 technology. They do have pretty great technology on how to handle noise and improve speech. I was pretty impressed when I tried it out for a few weeks.
This is typical what i had when trying Viron 9. During speech, I didn’t get to hear except it(no background noise). But When speech stop, background noise (TV, blower, AC…etc.) comes back.
For me, this was distracting and I felt that when someone is talking am isolated in a room and don’t have any surrounding senses.
I don’t have any experience with the Bernafon hearing aids. But from what I read up on it, its technology seems similar to the Sonic Enchant 100 I tried out, although that was just a guess. It does make sense if they share technologies, though, being sister companies and all…
That’s how noise reduction is working .if there is no competing sound to campare as nois and speech DSP won’t know what to reduce from spectrum.
Are there any issues with warbling when using feedback rejection?
They don’t whistle or screech like I’ve heard older hearing aids do, like a feed-backing PA system. When the feedback reduction cuts in they kind of make a “whirring” sound. It’s not very loud and is quickly suppressed, but it is noticeable. It only happens when I have them turned all the way up to my prescription, and in most cases I just turn them down a bit.
Thanks. It’s that ‘whirring’ sound that I am talking about. I play guitar, and it seems all modern aids misinterpret higher notes as feedback and then hop in right away to squash it. I’m working with my fitters at trying to make modern aids work for me, as I love the Bluetooth functionality. I have another appt Sunday afternoon… keep on tweaking!
So, I went and tried Philips hearing aids at Costco on Sunday. And I ordered a pair of the rechargeable aids. Overall, the feedback rejection is good - not nearly as invasive or ‘trilly’ as the KS9s. They will be here in two weeks. At that time, I will have both the KS9s and the Philips and I will see which I prefer in my everyday environment, and return the others. They sound promising, though!
I’m looking forward to the results of your comparison. I’ve heard good things about the KS9s.