Feedback suppression makes music sound out-of-tune

I have had analogs for 10 years, just changing to digital. My new Unitron Yuu instruments (still in trial period, fortunately) have an unexpected ‘feature’. The when feedback suppression is activated they seem to play back higher frequency sounds (ie above 2kHz) at a slightly different pitch. When I hear the direct and amplified sounds together a whistle becomes a warble and a piano sounds honky-tonk. It may not bother everyone, but as a musician I find it really horrible. I know it is connected to the feedback suppression, because when that is turned off, as it is in my ‘music’ preset, everything sounds fine.

Prior to trying the Yuu I trialled some Siemens Artis 2 for a couple of months, but did not notice anything like this. Both of these manufacturers describe their feedback suppression as ‘phase cancellation’, but the effect is quite different.

Has anyone else noticed this effect? I would dearly love to know which aids do NOT do this.

did you use the music program?
most music program disables the feedback canceller and noise reduction…
and I believe I read @ audiology online, the best way to appreciate music was to set the instrument with little or no compression (i could look up for the article)

By the way, to fully appreciate music you need an instrument with a vrey large bandwith…

Now to be honest we are not comparing apples to apples,
YUU is a high end instrument (released not to long ago) based on a new architeture while artis 2 is not really a highend instrument…

So YUU should outperform siemens by far… to make a fair comparison
it should be made against siemens centra…

While I do not dispense Neither of them, I have seen the pres. for the YUU and it looks like a very good instrument BUT you need to know your way around in the software as it does not look so user friendly

This im not surprise as Phonak / unitro us a very technical company.
I had browse phonak fitting software, and you have access to all the posible controls you want. Provided you want this…

The effect you refer to is called entrainment artifact, where the aid incorrectly identifies music as feedback. This can happen to any modern aid with phase canceling feedback suppression. There are a few things that can be done to overcome this on the Yuu though. What kind of fitting do you have (open or moulded)? How severe is your hearing loss? How well does the mould fit. You aud may try to turn off phase canceling for all programs if the fit of the mould is good - as feedback and hence entrainment will then not be an issue. Otherwise stick to the music program where phase canceling is disabled.

Thanks for the reply. First, my hearing loss is moderate, I think (40-60dB). I have earmolds with a fair bit of airspace because (a) occlusion causes unpleasant boominess of my own voice and (b) my canals are a bit bony, resulting in pain if I smile of laugh with a snug fitting. I changed from ITE to BTE for that reason.

Second, I did not notice this effect with the Artis 2, at least not that I can remember. (That’s the problem - I have given them back and can’t now double check or compare them). But I am pretty sure the Artis 2 coped with with high notes which it might have mistaken for feedback by generating the same pitch in opposite phase, making the high note softer. The Yuu seems to either play the high note back at a slightly different pitch or generate a reverse-phase note of slightly different pitch. Whichever it is doing, the effect is the same - it is a bit like like a chorus pedal or flanger, or perhaps a harmonizer, with a pitch offset of perhaps 20Hz (up or down - I can’t tell).

Third, you have suggested ways of avoiding using the feedback suppression. For general purpose hearing I (and my audioogist) think feedback control and a certain amount of compression is is desirable. (After all, why buy high end instruments if you can’t even do that?) So I have a manual preset for music, with no feedback control and minimal compression, and it works very nicely. The auto music is set up the same, but it only kicks in if there is absolutely nothing happening apart from music.

But through the day I hear music often, and being a muso I always take some notice of it, without even thinking. If everything sounds out of tune it is first perplexing, then annoying to find I have to switch presets to see what it really sounded like, when in fact I am busy doing something else. Often the snatch of music may have finished before I realize the problem is the aids and not the music itself.

That’s a long rant! I suppose the bottom line is that I would like to know whether digital aids exist whose feedback suppression does NOT cause music to sound out of tune, and if so which ones are they?

Most of the next gen devices are supposed to have good feedback management with reduced (or non-existing entrainment) including Oticon Epoq XW, Phonak Exelia and Starkey Destiny.

As far as turning off phase canceling it is only necessary to have it on if feedback is an issue. So if the aid does not FB without it (which I assume does not happen in the music program) then turn it off and still enjoy all the other excellent features of the device. The aud can also give the music program priority, which will switch the Yuu into music mode whenever music is present (even when mixed with speech which would have made it go the speech in noise program before the music priority was selected).

The artis has much slower FB Mx which is good for music but poorer with loose fittings. If you used the same moulds on the Artis then you can safely turn off phase canceling in the Yuu as it is generally a much more acoustically stable aid than the Artis.

As I said, my audiologist and I have looked at avoiding feedback suppression altogether, and it seems to be impractical in my case. However, your suggestion of prioritizing the auto music setting sounds hopeful as at least a partial solution.

But thank you especially for your use of the term ‘entrainment’, which I had not previously heard of, but which puts a name to my problem. I used this term to search out a Mark Ross article and the Starkey comparitive study of FBC in six aids. These papers suggest that ‘modulation effects’ can be produced by feedback suppression systems in response to some musical tones, and that some aids are worse in this respect than others. I take this to mean I may not be imagining the difference between the Artis 2 and the Yuu.

Now all I have to do is find which aids have more acceptable amounts and types of entrainment distortion.

It’s been my experience that entrainment is more of an issue with Siemens hearing aids, so I am surprised you did not have an issue with Artis.

One solution would be to try the Phonak SaviaArt. This hearing aid can automatically switch itself to a music mode when music is detected. I’ve worked with it quite a bit and haven’t run into entrainment issues. My guess is the Exelia is probably even better at this, but I haven’t worked with it much [yet].

for the money, I would not recomend a savia art, - if you are willing to put that amount of cash get an exelia… and pay a bit more…

I wear Savia Art open fit aids. I had trouble with entrainment and had to have the feedback suppression turned off. It would happen to me when I would hear any kind of beep or bell. For instance, I would get in my car and the seatbelt warning would go on. Every time the bell dinged, the sound would become more and more distorted and loud. By the time the last few dings were sounding, it was so loud my ears would hurt. I also had problems with microwave beeps and the chime on my grandfather’s clock. Amazingly enough, I didn’t have an issue with music.

Turning off the feedback suppression isn’t a problem most of the time, but there have been some times when I could have used it. I don’t know if others have this problem, but when I get stuck accidently hearing a very loud sound that is hurting my ears, I automatically cover my ears to protect myself. The problem is that now when I do that, I get feedback in addition to the loud sound because my hands cause a feedback loop. It is very frustrating and scary not being able to protect myself from unexpected loud noises (can’t afford to lose any more hearing!). When kids start screaming in the grocery store, I feel like my head is going to explode. Setting off those alarms at the entrances to stores is another nightmare.

I had the same problem with my Unitron moxi next 16’s. In trying to adjust out snapping and crackling, a tremolo sound was created for anything musical. They have removed the tremolo, but one aid is still snapping and crackling. I’m about ready to try a different brand as I’m still in the 45 day period.

The problem you describe is known as ‘entrainment’

It’s all about the quality of the feedback suppression. Some aids are more advanced than others at reducing feedback without becoming confused with external sound sources.

that is why you have a music program…

I believe Phonak or Unitron has a Automatic music program… in their auto pro…