# Hearing Aid Frequency Lowering: Not All Work Equally Well

### London’s Deafinitely Girly shows how the Phonak SoundRecover hearing aid frequency lowering scheme totally wrecks music… And when convolved with the groundbreaking research at Northwestern’s Auditory Neuroscience Laboratory that has connected the strengthening of the auditory cortex in musicians that leads to improved speech discrimination in noise, the results should give clinicians pause before enabling non-linear frequency compression on Phonak, Unitron, and now Siemens hearing aids.

Here at The Hearing Blog, we like to publish First Person Reports from people describing how technology that supposedly looks good on paper isn’t all it’s cracked up to be, such as the spacing on the electrodes in the Nucleus CI is too close, causing channel crossover. In Daniela’s case, it was her being a musician that exposed the known flaw in the implant design; and once again it’s London flautist and blogress Deafinitely Girly who exposes a major flaw in non-linear frequency compression (NFC) in Hearing aid update: My flute and Paper Aeroplanes

Yesterday was a music-filled day and I loved it.

You see, since coming home on Friday evening after work, broken from my week of partying, I wasn’t able to get the amazement that I’d been able to hear my neighbour’s daughter playing her flute in the downstairs flat.

I mean, if I could hear that flute, then surely I’d be able to hear my own.

So yesterday afternoon I decide to locate my flute and all my sheet music, both of which were buried right at the back of my spare room underneath the bed, where I hid them to try and dull the sadness I felt at not being able to play anymore when I moved in three years ago.

I loved my flute. As a violinist from the age of 6, I begged the rents to let me play the flute too, but my amazing flute teacher-to-be said I had to be 10 years old so that I was big enough to reach the keys without constricting my rib cage and breathing.

On my 10th birthday I had my first lesson. It was love at first hear and I flew up the grades.

When I lost more hearing in my teens, I just ploughed on through, playing my pieces an octave lower until I knew the tune then dealing with the silence the higher notes brought.

When I moved to London I sought out a teacher. He was amazing. He taught me sound visualisation so that I got the right diaphragm pressure to create the high notes I couldn’t hear.

But instead of being happy, I found myself being a ball of emotion in my fortnightly lessons. I cried frequently, sometimes out of sadness but mostly out of frustration that I was no longer getting the same enjoyment from my flute.

It affected everything and I could feel a growing resentment for my deafness � something I’d fought hard to overcome, so in the end I stopped my lessons and banished the flute to the depths of my underbed storage.

So you see, really, yesterday wasn’t really just about seeing whether the Sound Recover on my new Phonaks was going to help me get my flute back.

I started with some trepidation, warming up with a few Bach studies and Morceau de Concours by Claude Arrieu. The sound came. My lungs seemed horrified at the breathing I was asking them to do.

And the sound?

Well, I think I could hear the Sound Recover function’s adjustment of the higher notes but the problem was, these weren’t moved into a harmonious place, the notes were jarring with the pitch of the note I was actually playing.

It was so frustrating.

It would be like playing a piano piece with the left in the correct key and the right hand a semitone apart from what it should be. It was not pretty.

But it made me wonder – and if any knowledgeable hearing aid peeps could answer this I’d be eternally grateful – can the Sound Recover be moved so that the notes come out in harmony or even better an octave lower? Is there anything I can do to improve this? Or is it something that will improve over time?

What I can confirm is that yesterday I enjoyed playing more than I have done in a long time. My hearing aids definitely made the music better and because of this, I played better. I wasn’t nearly as rusty as I’d thought I’d be and practising the fast-moving high bits was easier and more rewarding because I wasn’t just hearing nothing. OK, it was a slightly out of key Sound-Recovered pitch, but beggars really can’t be choosers.

Return the hearing aids and get Starkey or Widex hearing aids instead: Phonak’s Sound Recover uses non-linear frequency compression, which you exquisitely describe:

Well, I think I could hear the Sound Recover function’s adjustment of the higher notes but the problem was, these weren’t moved into a harmonious place, the notes were jarring with the pitch of the note I was actually playing.

It was so frustrating.

It would be like playing a piano piece with the left in the correct key and the right hand a semitone apart from what it should be. It was not pretty…

What I can confirm is that yesterday I enjoyed playing more than I have done in a long time. My hearing aids definitely made the music better and because of this, I played better. I wasn’t nearly as rusty as I’d thought I’d be and practising the fast-moving high bits was easier and more rewarding because I wasn’t just hearing nothing. OK, it was a slightly out of key Sound-Recovered pitch, but beggars really can’t be choosers.

As I tweeted to you and Amy, what you want are hearing aids from Starkey with SpectralIQ or Widex with their Audibility Extender [application manual]: Both frequency lowering technologies maintain the harmonic structure, which is necessary for music.

So Yes, you can be choosy and bring back the music!

Unfortunately, Deafinitely Girly received her hearing aids for free via Britain’s National Health Service, so she is stuck with them for the next 3-5 years, unless she goes private.

### Just what is frequency lowering, why is it used, and how does the Phonak/Unitron/Siemens scheme differ from the Widex and dbx/Starkey schemes? And, just why did you say “dbx/Starkey,” anyway?

One of the underlying principles in audio engineering is that in stereo audio the information is the same in both channels below about 100 Hz; and this principle is used to derive the audio fed to subwoofers since the mid-1970′s, and later extended to 5.1 & 7.1 surround sound systems. In 1978, dbx extended this principle to disco sound systems, by first recognizing that low A on a bass guitar and the fundamental on a kick drum are both about 40 Hz; and then filtering the low frequency audio between 80 and 40 Hz, dividing the frequency in half (i.e. generating a new spectrum between 40 & 20 Hz), and adding it back in, to give the music an extra bass kick. They gave their system the descriptive name of the “dbx 120 Subharmonic  Synthesizer;” and to this day, 35 years later, it’s still available, with prices in the product family starting at under $200. Fast forward to the April 1992 ASHA Convention in Atlanta, where a small Israeli company named AVR Sonovation introduced a radical new hearing aid concept called the TranSonic: Ithad a bodyworn processor the size of two decks of cards, with a wire running to a BTE earpiece with the mic & receiver. Instead of just amplifying the sounds, it actually took the input above about (IIRC) 2500 Hz or so and shifted it down: For the first time, people who had profound losses in the high frequencies – Extreme ski-slope with high frequency cochlear dead zones (≥≈90dB HL) had access to the high frequency unvoiced consonants such as /s/, /sh/, /p/, /t/, /Θ/, /k/ & /sh/, drastically improving their speech discrimination; and in fact this author fit five of these devices to grateful patients. [We aren't sure which exact frequency lowering scheme they used, as they simply said they "threw away" the excess cycles. If anyone knows, please write us.] In 2008, Phonak released their SoundRecover frequency lowering algorithm, which first compresses the high frequency spectrum above a certain kneepoint, and then shifts this new spectrum into the lower frequencies. Joshua M Alexander PhD at the Purdue University EAR Lab has conducted research into this, and came up with a set of frequency kneepoint-compression ratio locked pairs which are the defaults; while in the advanced settings the pairings can be unlocked. Last year, their Sonova sister company Unitron released it; and in January 2013 Siemens released their Micon hearing aid line with this feature. [For a very good description of the nuts and bolts behind this strategy, see Skepticism Lab: How Low Can You Go: A Tale of One Frequency Lowering Technique by Purdue audiology students Alyson Harmon & Casey Adkins. Their paper would be rated as excellent; but it gets docked for its not challenging the claim on page 3 that "apart from speech, SoundRecover also improves… listening pleasure, such as in the clarity of music." What we need to stress is that although non-linear frequency compression works well for speech, by it's very nature it destroys the harmonic structure of music, as the harmonic frequencies are shifted to frequencies not harmonically related to the fundamental note: This is exactly what Deafinitely Girly reported.] Shortly after SoundRecover came out, Widex answered back However, in 2006, Widex struck first with their awkwardly named Audibility Extender (an annoying eight syllables when the voice prompt announces it during program shifts) in their Inteo instrument line [For this correction, see comment #1 from Anders Jessen]; but in fact it basically divides the signal in half or into one-thirds, maintaining the harmonic structure, and hence enjoyment of music. Then, in fall 2011 Starkey released their SpectralIQ, which is an exact high frequency version of the dbx subharmonic synthesizer… All that is old, is new again! ### Differences between the Widex and Starkey frequency lowering methods: Although similar, SpectralIQ differs from the Widex scheme in that the original higher frequencies are left in place, although the gain in the higher channels can be reduced if excitation of cochlear dead zones is not desired (and there is controversy in extending the response into these zones). In addition, SpectralIQ processing only divides the fundamental in half, while Widex can also divide it into thirds. However, the Widex system is not without flaws: Unlike Starkey, which provides the industry’s best per-program granularity providing flexibility to the clinician and patient, Widex ties the Audibility Extender (and also Zen, Phone+, and streaming audio) gain, noise reduction, microphone steering, and feature selections to the settings in the Master program, which must be set first. What’s more (and unlike SpectralIQ), Audibility Extender cannot be engaged while receiving streaming audio from the Dex accessories, which is a Major Flaw: If it works so well, why would you want it locked out when using the phone?! Update (3/20/2013) According to this comment by Dan Tibbs AuD of Widex, apparently they got the message that if a patient needs Audibility Extender on the Master program, they need it across the board; and the new Dream has fixed this flaw. However, the Super, which has the same chipset as the Clear, apparently has not yet had this bugfix applied. ### Now, about that linkage between music and speech perception in noise: The importance of music appreciation has been preached to the hearing impaired by Dr Mark Ross for over a decade; but most of it was based on anecdotal evidence and early research. However, the Auditory Neuroscience Laboratory at Northwestern University, led by Nina Kraus PhD, has produced extensive peer-reviewed research proving the link between playing a musical instrument and speech discrimination in noise; which you can see on the labs’ Neural Encoding of Music and Speech in Noise pages. From the Music page, Dr Kraus writes, Musical experience has a pervasive effect on the nervous system. Our recent articles show that lifelong musical experience enhances neural encoding of speech as well as music, and heightens audiovisual interaction. Our work suggests that musicians have a specialized neural system for processing sight and sound in the brainstem, the neural gateway to the brain. This evolutionarily ancient part of the brain was previously thought to be relatively unmalleable; however, our studies indicate that music, a high-order cognitive process, affects automatic processing that occurs early in the processing stream, and fundamentally shapes subcortical sensory circuitry. Just in the last three years, the lab has churned out the following outstanding R&D of which hearing care professionals of all stripes — But especially pediatric audiologists – should be well aware: 2012 Parbery-Clark, Anderson, Hittner, Kraus. Musical experience strengthens the neural representation of sounds important for communication in middle-aged adults. Frontiers Strait, Parbery-Clark, Hittner, Kraus. Musical training during early childhood enhances the neural encoding of speech in noise. Brain & Language Skoe & Kraus A little goes a long way: how the adult brain is shaped by musical training in childhood. J Neurosci Parbery-Clark, Tierney, Strait, Kraus Musicians have fine-tuned neural distinction of speech syllables Neuroscience Kraus Biological impact of music and software-based auditory training J of Comm Dis Strait, Chan, Ashley, Kraus Specialization among the specialized: auditory brainstem function is tuned in to timbre Cortex Parbery-Clark, Anderson, Hittner, Kraus Musical experience offsets age-related delays in neural timing Neurobiol Aging Kraus, Strait, Parbery-Clark Cognitive factors shape brain networks for auditory skills: spotlight on auditory working memory. Annals of the NYAS Anderson, Parbery-Clark, White-Schwoch, Kraus Auditory brainstem response to complex sounds predicts self-reported speech-in-noise performance JSLHR Kraus, Anderson (2012) Hearing matters: Hearing with our brains. Hearing Journal Anderson, Kraus cABR: A neural probe of speech-in-noise processing Proceedings of ISAAR 2011 Song, Skoe, Banai, Kraus Training to improve hearing speech in noise: Biological mechanisms Cereb Cortex 2011 Strait, Hornickel, Kraus Subcortical processing of speech regularities predicts reading and music aptitude in children Behav and Brain Func Parbery-Clark, Strait, Kraus Context-dependent encoding in the auditory brainstem subserves enhanced speech-in-noise perception in musicians Neuropsychologia Marmel, Parbery-Clark, Skoe, Nicol, Kraus Harmonic relationships influence auditory brainstem encoding of chords NeuroReport Strait, Kraus Musical training shapes functional brain networks for selective auditory attention and hearing speech in noise Frontiers in Psych Parbery-Clark, Strait, Anderson, Hittner, Kraus Musical Experience and the Aging Auditory System: Implications for Cognitive Abilities and Hearing Speech in Noise PLoS ONE Strait, Kraus Playing Music for a Smarter Ear: Cognitive, Perceptual and Neurobiological Evidence Music Percept Skoe, Kraus Human subcortical auditory function provides a new conceptual framework for considering modularity. In: Language and music as cognitive systems Tierney, Parbery-Clark, Skoe, Kraus Frequency-dependent effects of background noise on subcortical response timing. Hear Res Anderson, Kraus Neural encoding of speech and music: Implications for hearing speech in noise. Seminars in Hearing Anderson, Parbery-Clark, Han-Gyol, Kraus A Neural Basis of Speech-in-Noise Perception in Older Adults Ear Hear Hornickel, Chandrasekaran, Zecker, Kraus Auditory brainstem measures predict reading and speech-in-noise perception in school-aged children Behav Brain Res Parbery-Clark, Marmel, Bair, Kraus What subcortical-cortical relationships tell us about processing speech in noise. Eur J Neurosci Song, Skoe, Banai, Kraus Perception of speech in noise: Neural correlates J Cogn Neurosci 2010 Kraus Musical training gives edge in auditory processing Hear Journal Strait, Kraus, Parbery-Clark, Ashley Musical experience shapes top-down auditory mechanisms: evidence from masking and auditory attention performance Hear Res Kraus, Chandrasekaran Music training for the development of auditory skills Nat Rev Neurosci Chandrasekaran, Kraus Music, Noise-Exclusion, and Learning Music Percept Kraus, Nicol The musician’s auditory world Acoustics Today Anderson,Chandrasekaran, Yi H, Kraus Cortical-Evoked Potentials Reflect Speech-in-Noise Perception in Children. Eur J Neurosci Anderson, Skoe, Chandrasekaran, Zecker, Kraus Brainstem Correlates of Speech-in-Noise Perception in Children. Hearing Research. Anderson, Kraus Objective neural indices of speech-in-noise perception. Trends in Amplification Anderson,Kraus Sensory-Cognitive Interaction in the Neural Encoding of Speech in Noise: A Review.JAAA Anderson, Skoe, Chandrasekaran, Kraus Neural Timing is Linked to Speech Perception in Noise J Neurosci Chandrasekaran, Kraus Music, Noise-Exclusion, and Learning Music Percept ### Connecting The Dots: Musical training has become an important part of auditory therapy/rehabiitation; and it is extremely important that the hearing aids and/or CI’s fully support this vital activity, and don’t interfere. Although on the hearing aid side, non-linear frequency compression can contribute to high frequency audibility of unvoiced consonants to improve speech discrimination, as flautist Deafinitely Girly discovered it also destroys music, and we explained why. The same goes for spacing CI electrodes too close together, as Melbourne pianist Daniela Andrews discovered and we explained why. These two deaf musicians have, with their First Person Reports, provided a window into how technologies that may look good on paper can have unintended, detrimental consequences. You can e-mail “Deafinitely Girly” at deafinitelygirly@googlemail.com and follow her on Twitter at @deafgirly ### Comment problems: It’s been brought to our attention from several of our readers that they were having their comments rejected by the Akismet plug-in for WordPress as spam. This is unacceptable to us; and we are soliciting suggestions for a replacement. Unfortunately, we have to use something to screen for spam, as we were receiving over 100 spam comments per day at its’ peak. In the interim, to save retyping, we recommend selecting & copying all of your text to the clipboard: If your comment is accidentally rejected, simply paste it into an e-mail message, put “Rejected Comment” in the subject line, and send it to us at Dan@Snip.Net and we’ll manually post it for you~ ### About the author ##### Dan Schwartz Electrical Engineer, via Georgia Tech ### 7 Comments 1. ###### Anders Holm Jessen March 19, 2013 at 2:48 pm Hi Dan, Read your links about frequency lowering with interest. Generally I agree. I just have to point out that Widex actually introduced the Audibility Extender (I agree on your feelings for that name) with Inteo in 2006 and was them followed by Phonak a few years later. It’s an interesting area to follow now when other players are beginning to catch up and come with quite a variety of different implementations. Best regards, Anders • ###### Dan Schwartz March 19, 2013 at 10:45 pm Anders, thank you for the correction! I was out of the hearing healthcare profession from 1995 to 2010, so I appreciate you bringing me up to date. 2. ###### Dan Tibbs March 20, 2013 at 2:03 pm Hi Dan, Interesting piece…the only update I will mention is that your comments RE: AE and not working with phone, DEXes, etc is true for earlier Widex models (including Clear), the recently released Dream models do allow AE to work with all those conditions based request from End-Users and Customers for it to do so. Thanks again! Regards, Dan 3. ###### Rachel March 20, 2013 at 4:26 pm I find it frustrating that most audiologists (100% in my experience) are really at a loss when I bring this up. It seems that sound quality, and as much of a “natural” quality isn’t the emphasis when it comes to digital hearing aids. Against strong objections, I returned my$ top-of-the-line digital aid and asked for an analog. After spending years dancing with a professional ballet company, there was no way I could even recognize pieces that I had danced to for a decade.

Since one of the chief complaints I hear from persons who become hearing impaired later in life (industrial loss, aging, etc), is that the hearing aids don’t sound “natural” or “normal”… I would think this would be a priority for the population in general. Seems not.

Also… anyone else royally annoyed by those “smart” digital aids that automatically cut out with any loud sound? Thanks, but no thanks

4. ###### Emil Toma
April 6, 2013 at 1:25 pm

Hi Jennifer,

I suppose you’re already confident with information coming from GNResound (ReSound, Interton, Beltone). I’m writing this just to confirm that Milano platform, having particular experience with Crisp370/80 BTE from Interton, has astonishing results among my clients. I encountered really difficult cases, coming from other distribution chains, where no other 6-9 channels instruments were able to do the high frequency compensation for profound loss in the manner that Crisp did. Starting with this summer, a wireless (remote) microphone should be available for Crisp and Cosmo (another great instrument, RIE, on Sydney platform, discrete and strong). Although I’m not familiar with, I suppose the Live family from ReSound is doing basically the same job, at least the features on paper are on par (or better) with Crisp. ReSound families have already an wireless microphone available.
Personally, every time I’m listening a Crisp, it’s a song. A warm one. A really broad spectrum, soft touch, sharp edges, integration, a long-expected listening experience. No advertising intention, just sharing experience.
A thought.

5. ###### Jodee
October 13, 2013 at 5:03 pm

Editor’s Note: This comment is from a member of the Association of Adult Musicians with Hearing Loss who assists two other musicians, including one who has a severe-to-profound hearing loss fit with Phonak Solana ITE hearing aids. I asked this lady to copy & paste her correspondence in a comment, as it is quite telling on a number of planes.

Thank you, Dan! Thank you for reaching out to my other friend, too. He’s also one of the best musicians around but, no longer plays. Sixty years of music still in his head, though. Like my friend, he also played professionally for 60+ years, and well, everybody who plays country music in our area knows him.

My musical partner has Phonak Solanas, new in Feb. 2012, custom-molded ones. The VA paid for them. He worked in a noisy factory environment for 30 years, no ear protection. We live in south Texas. I told him about you and I corresponding.

He says he thinks there are four programs (channels?) but just one program is activated. You pointed out that there must be two. I know for a fact the audiologist turned off the music part of something in his programs – I saw her do it and asked her about it. The distrust came when she wouldn’t explain why she did it.

I want to like her, she’s really smart but it just feels like she’s always trying to get rid of us. I don’t want to make her mad, we just want to feel assured everything has been done that can be, not just be sent away wondering and feeling patronized.

My friend says his Phonaks have another program but when he switches to it, it gets … softer … he can’t explain. He “can hear, but not as good. Tones are missing here and there.” He can’t use it. Program one goes “ding ding ding” and the other just “ding” when he switches.

I talked to him at length today. He hears pretty well through his speaker phone. His everyday program gets him by, we’d hate to mess with it.

He says the background noise level is awful with his hearing aids. Friday we went to a busy diner and sat next to a table of 10 young people. I asked him to let me hear his hearing aid. He gave me one. I could hear the background noise louder than his voice to me, as if the volume to his voice was actually somehow turned down quieter than the total diner noise all mixed together.

His music programming (?) is also a problem. He’s ok with one or two musicians playing in the room, but when all the musicians come together (with varying degrees of noise, proficiency, timing – so many factors!) he can’t hear.

I think he sings in his head and keeps up that way, with me as a visual/percussive guide. I play Western Swing/Country rhythm on a classical guitar, using basic chords and trying to just keep a steady rhythm, sitting right next to him. I try to make adjustments to my playing and keep it simple, with the sound hole facing him. He often glances up at me to make sure we’re still at the same place musically. Sometimes I play on the off-beat just to keep time for him in the noise, if that makes sense. Whatever it is, it works. Did I say I love playing with him?

My friend’s hearing aids just turn off if it gets too loud – ACK! How incredibly distracting in the middle of his awesome solos! He has to keep his composure – without skipping a beat. I so admire him for going on. He’s a real pro.

Oh and one day, he got OBSESSED with his guitar having a fret rattle! I kept telling him no, it was ok, it really wasn’t bad and not to play so hard but he didn’t believe me. He LOVES to collect guitars, and he loved that guitar, a Fender. He had it in the shop to sell, but one day took it back, adjusted the neck, played it, made more adjustments, adjusted the saddles (he loves low action/light strings – he plays lead.) But he called me to come over and listen for the rattle for him.

It rattled, but not badly. Finally in desperation I asked him to let me hear. He gave me his left hearing aid and I listened. I wanted to cry. I am now, sorry.

There’s an odd electronic rattle that DOES sound like frets buzzing. It’s horrid. I don’t see how he can stand it – over stimulating. It was worse on that guitar, and even worse on certain pick-up positions. We took that guitar back to the shop and all involved decided that particular guitar just had a weird tone.

Still, I heard that awful rattle clatter he hears. It’s totally over-stimulating – but then I don’t wear hearing aids at all.
Seriously, though it’s hard for me to hear a lot of noise or play with people who are out of tune. I constantly think it’s me when someone else is out of tune. But it’s not me. Very distracting! I can see my friend’s face and I know he hears it, too. There’s a wavering when one string is out of tune with another instrument’s string of the same note ….

My hard of hearing friend and mentor won’t let me say anything about it! I’d say, “Someone’s out of tune and it ain’t me!” My friend says I’m his ears and I’m very proud of that. I don’t want him to become isolated, he’s a people person.

Then there’s the pitch problem … not sure if it’s JUST his hearing aids or his ears, too. We played with hearing aids in and out, and I listened, too. Same pitch/tone problem with them in or out. With his hearing aid, I HEARD the out-of-tune after-tone bit, a half-step lower than the original note, during and continuing still (echoing?) after the original note had gone away.

One additional note, my friend told me that sometimes “like on the radio, I can hear one song great, everything’s clear and I can hear the tune and melody, but the next song? Can’t hear. Like it’s recorded differently or in a different key or something.”

Dan, he’s amazing. I can send you a video of him playing but I’d have to ask first. I don’t care if he makes mistakes (he never did before losing his hearing.) Ok I’m in tears again. He’s just so amazing. He’s the only man I ever boldly went up to and gave him my number. Asked him to give me guitar lessons, that I’d been waiting my whole life to play like that. I’m his first and only official student. We’ve been partners for almost 2 years. He’s been playing professionally for 60+ years. A musician’s musician.

No wonder he gets so tired when we play. He must be mentally exhausted trying to hear. He has trouble sleeping at night, after he takes his hearing aids out. Maybe it’s not related but I think his mind is still trying to hear.

None of us knows when our time is up. Yet at 80 years old, it seems it looms closer for him. It isn’t fair to wait 1-1/4 years until the VA will pay for new aids when the ones he already has might be tweaked with a little time and effort. He shouldn’t have to but he would and could pay for the time to have them done right, IF we could find someone we trust to do it.

I hear the noises on his hearing aids, and another audiologist said she did, too. But that audiologist works with the ENT surgeon and it seems like they want to sell him an implant – and he doesn’t want to risk what he has now. It seems like we get a different story about things every time we go in!

He’d rather limp along like he is now than get an implant or mess with his everyday TV, phone, conversation program, if that’s what he has to sacrifice.

Anyway, there’s so much more to the story, but this is long enough for now! Thank you so much for your interest in my friend. He’s a remarkable, very special person who made a very valuable life-long contribution to the local country music scene and I love him very much.

Thank you for being a source of support for lurkers like me.