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Oticon and Compression question

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A few years ago, I bought Resound 3d Hearing aids and had nothing but problems with them, despite being relatively happy with my previous Resound hearing aid.

So I bought the Oticon Opn 1 hearing aids and abandoned the Resound 3d and will probably never go back to Resound as I have found Oticon far better for me in noisy environments.

You can view my previous lengthy posts on the Oticon as well as my hearing chart to get some idea of the initial problems that I had with them and how they were resolved which might give better understand of my current issue and question as I suspect that my initial problems and current problem are all related. But in brief.

When I first got the Resound 3d and Oticon OPN 1’s a couple of years back, that was my first time ever wearing a hearing aid in the right ear. I only ever wore hearing aid in the left ear on my previous very old Resound.

With the OPN’s I started off with domes, double vent and power domes and open domes - I honestly can’t remember which ones and which order. After a lot of tweaking, changing domes, getting a bigger receiver and then moving to moulds we resolved the dual problems of feedback and more critically battling to hear on the cell phone and in noisy environments (I use my left ear for the phone). I think the fundamental problem was that domes were not sufficient enough for my left ear. The right ear from day one (apart from some high frequencies initially being far too loud), the amplification and dynamic range was there in the right ear. But the left ear, the domes were not enough.

Since moving to moulds, doing tests and adjusting the frequencies more in the left ear to boost the volume and gain etc and slightly reducing the volume in the right ear, I am largely happy with the Oticons. They are far better in noisy environments than any of the Resounds I ever wore and I like the open sound of the Oticons.

Now to the question.

Due to Covid, I have not been in to see my audio for a while. I went this week and there is a new audio at the company that I use. We had a chat about my hearing issue which is basically the right ear has always sounded louder than the left ear and is particularly noticeable when streaming movies or in very noisy environments. Not so noticeable in quiet conversation environments.

I mentioned to him that the default volume on the streamer app is 14 and when I increase the volume on the RHS aid the volume goes up noticeably more than when I do the same for the LHS aid. I feel like going from 14-15 is three times louder on the right than doing the same on the left. He said that this is because the left ear has much more compression which affects the volume somehow.

This also might explain why the right ear sounds louder than the left ear because in the right ear I am getting more range of sound, whereas the left ear is more compressed. To put it another way, sounds in the left ear have always sound flat, whereas the right ear all the sounds are more dynamic, more sharp, more crisp etc. I wouldn’t say that the left is muddy, but leaning slightly in that direction - it lacks the sharpness especially in the higher frequencies which is probably what makes the right ear sound louder as high frequencies can seem loud.

For anyone who understands hearing aids, does the explanation that compression is the reason why the right ear sounds louder and all the sounds are more dynamic, crisp and precise where the left aid I feel like it’s flat and I am missing some of the range and this makes the left aid sound “softer”. I am not 100% certain whether problem is volume as in low frequencies and possibly higher frequencies not boosted enough, or whether it’s compression which is slightly muddying the higher frequency sounds making it sound softer and flatter?

Or does compression have nothing to do with my problems of getting the aids balanced volume wise?
While I had a lot of issues with the Resound 3d hearing aids, the volume imbalance (even if it’s not actually volume that is the problem) was considerably less on the Resound 3d than on the Oticons. As far as I can recall I streamed movies on the Resound with both aids at the same volume, but with the Oticon I watch the left on 18 and the right on 14 and even then some sounds are still louder in the right ear particuarly the higher frequencies.

I am just wondering if Oticon are not the best aids for compression if this is causing my “volume imbalance” as I did not have this issue with the Resounds. I do feel that the volume in the left aid is not as loud as it should be. Having said that the Resounds (both the 3d and the previous model) were always too loud in noisy environments.

Can anyone advise on the compression question and offer any explanation on why Resound doesn’t seem to have this issue and whether Marvel or another aid would offer the benefits of Oticon but address this compression problem causing volume imbalance and a feeling of sounds being flat and lifeless in the left aid. The right aid is perfect and only seems louder because the left aid is not working as it should be.

Thanks in advance for any advice.

3 people in this conversation17 min readJump to latest
Edited

So let’s start with a basic understanding of what compression is. In screenshot #1, there’s an example between 0-40dB input (we can nominally call this soft sounds, you have a gain of 30 and a compression of 1, or flat gain. Between 40-80 dB (we can nominally call this moderate sounds), you have a compression ration of 2, or the amplification is no longer linear, but compressed twice as much (2 dB increase in input gets 1 dB increase in output). Beyond the 80 dB input, the compression ratio is the same at 2. This is just an example, yours may be different.

The reason compression is done is because usually loud input sounds doesn’t require an equally loud output sounds from the amplifier after the gain. The gain can be less, yet the patient can still perceive the loudness just the same.

Also, the example shown is only for 1 frequency. As you know, your hearing loss changes over the frequency range. So if you cut the hearing frequency range into 16 different sections (or handles), now you get a third variable (frequency) introduced. So compression ratio is not a simple number, it varies between the Soft/Moderate/Loud areas, and it also varies over the frequencies. You can see this in the table in screenshot #2, which is the Fine Tuning Gain Control section of the Oticon Genie 2 software.

So for your audi to make a statement that you’re feeling flat on the left ear amplification and much louder perception on the right ear amplification with a smaller volume increment is because “your left ear has much more compression.” is an overly simplistic generalization. If you really want to know what kind of compression ratios Oticon has assigned to your hearing loss’ amplification, ask your audi to print out a screenshot of your profile like the one I’m showing here for mine (in screenshot #2). I bet that it varies all over the place and is not just 1 number for the left and 1 number for the right HA.

Your hearing loss is very peculiar and asymmetrical. Your right hearing is better than your left hearing in the low to mid frequency range, but then they flip flop on the mid to high frequency range (the left hearing is better than the right). This will give you different hearing perceptions depending on the kind of sounds you hear, whether it’s the high sounds or the low sounds.

Anyway, I don’t really know why your left ear amplification sounds more flat on the right ear. I just don’t buy your audi’s simplistic sweeping explanation that it’s because the left HA has more compression than the right HA. Again, ask for your Gain Control screenshot with the compression ratios display and see for yourself if this is the correct generalization in the first place.

The brain perception is highly complex and I wouldn’t presume to try to blame it on anything conclusive like “it’s because Oticon is doing a bad job on compression.” On top of that, like I said before, you have a very asymmetrical hearing loss between both ears over the frequency range, which no doubt would exarcebate your volume, balance and sound characteristic perception.

The compression Oticon selected for each frequency range and input level range (soft/moderate/lout) depends not only on your hearing loss at each frequency, but also depends on other factors like the goal the fitting rationale. You’re probably using the Oticon VAC+ fitting rationale. Have you tried the other standard fitting rationales also available in Genie 2 to compare the differences. You have 3 remaining programs where you can have your audi assign 3 different/other standard fitting rationales so you can do A/B/C/D comparison between them live simply by toggling between the 4 programs. Read the third screen shot below to understand better how/why/where Oticon get their prescribed gain values from.

Another simple thing to try is if you really feel like there’s an imbalance perception in volume and one side sounds flatter than the other, have you tried asking your audi to simply add a few more gain clicks on EVERYTHING on the left side until you feel like it’s better balance for you? Then you can further fine tune the gains between the soft/moderate/loud sections separately after you’re getting somewhere with it.

So don’t allow your audi to quickly dismiss the issue you have as a compression issue. Sure, different HA brands tend to have their own proprietary fitting rationale, beside the other 3 standard ones for adults. Maybe the other brand’s own fitting rationale just by pure luck ends up working better for your complex asymmetrical hearing loss compared to the Oticon VAC+ fitting rationale.

Or maybe your audi hasn’t simply tried a few of the basic adjustments that can be tried to fix the volume imbalance and sound perception for you. The 4th screenshot below show some Sound Control options to make the sound perception Brighter or Fuller, and to have soft sound perception be more Detailed (sharper) or just focus on more Comfort (duller).

The very last screenshot is a little chart on (Wide Dynamic Range Compression). Probably all major brands HAs do this. Without WDRC, you’d have to keep adjusting your volume all day long. In quiet place you’d be turning up your volume, in loud places, you’d be turning down your volume. What this chart drives home is that your impaired hearing range can be more limited than the normal full hearing range, and that your impaired hearing range can vary quite a bit over the frequency range, so compression has to be set quite differently at different frequencies. Compression is highly complex and highly dynamic, but thankfully can be highly automated so you don’t have to fiddle with anything much.

There’s so such thing as “bad compression”. Compression is determined through a complex set of variables. You can’t really fix compression and make it “good”, it’s just too complicated. But there are many adjustments and things you can try: overall (and eventually fine tuned) volume balance adjustments, various tonal adjustments, and 3 different standard adult fitting rationales plus a mfg proprietary fitting rationale to try out. If you’ve tried it all out and still no help, then OK try other brands and their proprietary fitting rationale until you find one that works best for you.

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@Volusiano I agree with you that the compression is an oversimplification. I don’t actually think that my audio thinks it’s just compression rather a variable amongst other variables. I think the key issue is that he is trying to explain to me in terms that I understand why I am having these difficulties and I latched onto his comment about compression when talking about why increasing the volume in both aids does not result in same amplification.

I suspect the main issue is the very peculiar and asymmetrical hearing loss that I have and the fact that the right ear is better in the lower frequencies (which is why I probably get a feeling of more energy in the right ear). Even with the Resound, there was a slight imbalance but it was always far less than the Oticons. I only actually noticed the imbalance with the Resound when I started comparing the Resound with the Oticons.

I would say more that compression is a factor because naturally when you compress sound, you are in effect losing some of the sound as there is no such thing as lossless compression. It would explain why there is a sense of a loss of dynamics in the left ear if there is more compression there than the right. I don’ t know.

The audio that I saw on Tuesday did actually adjust upwards some of the frequencies. I watched a couple of programs last night and I have to say it is a lot better. I was watching both ears on 14 and 14, but while improved, I do still get that sense of energy in the right ear which is lacking in the left. I have to watch movies (where the imbalance is more noticeable as there is more than just talking) and see. But it may be a case of having to bump up the frequencies a bit more in the left ear. Particularly the higher frequencies.

I think the reason why I am a bit confused about the dome/mold and having to increase the frequencies several times over a period of time is it doesn’t seem to me that the tests are accurately prescribing my needs for my left ear properly. They have between them adjusted the frequencies and no doubt speech mode etc quite a few times over the lifespan of the aids. For all my complaints with the Resound, I never had this particular problem. The Resound issues were completely unrelated to this.

I will ask him about creating more programs and trying the other fitting rationales as I think that is a very good idea. It may just be the Oticon fitting rationale does not work well for my left ear.

Thank you for the feedback. it is very helpful.

You’re correct that the sense of sound energy emanates more in the lower frequency range than in the high frequency range (high range gives you the sense of sharpness, not energy). And often energy is perceived as volume. The hearing aid (almost all of them) can only compensate so much for energy loss in the lows simply because of the receiver physical size limitation. They’re tiny little speakers after all.

You do have loss in your right hearing on the lows, but the 20 difference in the loss between the right and the left is probably significant enough that the energy/volume perception remains because the tiny receiver on the left simply can’t make up ground for that difference. It can only amplify so you can barely hear on your left ear, but probably not loud enough to perceive as equal loudness to the right HA. The first screenshot below is the page on Genie 2 for the Oticon OPN that gives you some Power Bass perception. It shows the option on the iPhone page, but you have the same option on the TV Adapter and the ConnectClip as well. You can try to set it to High on your left HA, and maybe less (Off or Low or Medium) on your right HA to see if this also helps with the volume imbalance perception.

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Another little known fact about the Oticon VAC+ fitting rationale is that it’s programmed a little more unconventionally on reverse slope loss. For people with reverse ski slope loss (worse hearing loss in the lows and better hearing loss in the highs), the conventional wisdom is to compensate more for the worse loss in the lows through amplification, and compensate less for the not-as-bad loss in the highs; basically to flatten out the hearing capability in theory. But what Oticon found is that this conventional approach is not helpful when it comes to speech understanding, that the stronger amplification in the lows to compensate for the loss actually ends up muddying up the clarity of speech for those patients. They found that by using not as strong amplification on the lows, and focus on amplification on the mid to high (depending on the hearing loss), those patients get much better speech clarity. Since their VAC+ (Voice Aligned Compression +) fitting rationale gives the focus and priority on speech clarity, they decided to implement the strategy as described above based on their findings for reverse ski slope loss patients. Some people on this forum go for Oticon HAs specifically because the VAC+ rationale gives their reverse ski slope loss better speech clarity.

Now for most folks who have symmetrical hearing loss, this odd ball but effective strategy for speech focus works out well for them because their symmetrical loss results in a balanced hearing. For folks like you with asymmetrical hearing loss (you almost have ski slope loss on the right ear and semi reverse ski slope loss on the left ear in the lows, then ski slope loss in the highs), it can wreak havoc on the balance. Your left ear doesn’t get the amplification boost in the low that it needs due to the VAC+ strategy of unconventional reverse ski slope loss treatment, while your right ear gets the normal conventional ski slope treatment by VAC+, furthering the imbalance in the low that already exists.

That’s why I recommended that you try the other 3 standard fitting rationales, because they may have a more conventional approach to hearing loss treatment. But then you may not get as good speech clarity on your left ear as you could with VAC+. Isn’t that why you ditched the Resound 3D because Oticon VAC+ fares better for you in noisy environments (meaning better speech clarity in noisy environment). So maybe no matter what you settle on, it’s a compromise game you may need to play, between better speech clarity and better volume balancing.

Another thing you can try is the Speech Rescue technology in the OPN, if you haven’t tried already. Maybe if you enable it for both ears to get better speech clarity, you can have your audi boost up the lows in your left ear manually to compensate for the volume imbalance, but Speech Rescue enabled will compensate for the loss in speech clarity you may experience when boosting up the lows in your left ear. The screenshot below shows the Speech Rescue page. With the kind of loss you have in the highs, I’d recomment you go with the 2.4 configuration so your lowered destination region will be in the 1.5-2.4 KHz range, where your hearing loss is minimal compared to elsewhere.

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I am going to have to watch more movies over the next few weeks and when I visit my family next month I will see how I manage with other people around. At the moment, I don’t have too much chance to test my aids because we are still in partial lock down, restaurants etc are closed.

The impression that I am getting at the moment is that the volume is now roughly equal, with more energy and dynamics in the right ear and higher frequencies sounding sharper in the right.

When I next go out for a long drive, I will test the music channel in the car and see if it compares to my experience of watching movies and tv programs at the moment.

I think that I need to work out whether the higher or lower frequencies (or both) need to be adjusted upwards. Whatever he has done has reduced the feeling of a volume imbalance and I think it may be more the higher frequencies are a bit soft in the left ear.

I will play use the aids for a couple of months on these settings before asking the audi to make any further changes as I am uncertain as to whether the lower, mid or higher frequencies are the issue at present.

I will update this topic in a few weeks.

Edited

There’s probably going to be a lot of playing around and testing things out to finally arrive at a setting that works out best for you.

I don’t know if you’d feel comfortable with programming or not. If you are, it’s worth a try because it’d be so much easier for you to experiment with a ton of things on your own without having to depend on your audi. The software can be downloaded and installed for free on a PC, all you’d need is to buy an interface device like the Noahlink Wireless (I just bought a used one from eBay myself for about $120 + $8 for shipping before tax. There’s a whole DIY section in this forum where you can get all kinds of DIY help from.

That is also an option, however I felt that I just didn’t know enough about hearing loss for it to be a good idea.

Whatever the audio has changed this week, I feel has really made a difference. For the first time since I bought the Oticons, I don’t feel that the volume differential is that noticeable when watching tv through the streamer. So far I am watching everything on 14/14.

So I just have to listen to various environments and see whether that sense of balance is the same everywhere and then focus on what I feel is missing, which at the moment seems to be a lack of sharpness (treble) in the left.

So sorry @flashb1024, I meant NoahLink Wireless but I wrote down Express. I’ve fixed that typo in my post now. You want the NoahLink Wireless because it’s the only thing compatible with the More if you want to be future-proof. But if you have the OPN, it may not be able to do a wired firmware update for you though (although it may, I just don’t know). You may have to go have your audi do firmware updates on the OPN and OPN S for you. See compatibility chart below.

By the way, the used NoahLink Wireless I mentioned on eBay was already all sold out. They had 6 of them.

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