What Is Frequency Compression in Hearing Aids?
Frequency compression is the process of shifting sound from one pitch to another to make speech sounds more audible. Most age-related hearing loss occurs in the high-pitches, which is why women’s voices are harder to hear for those with a typical age-related hearing loss. Amplification of high-pitch speech sounds is the typical remedy, but due to the progressive deterioration of the inner ear, speech may remain unclear in cases of severe hearing loss. As a workaround, it can be helpful to shift high-pitch speech sounds down to lower pitches, where the missing consonants can be heard again.
Dr. Cliff Olson, Audiologist and founder of Applied Hearing Solutions in Anthem Arizona, discusses Hearing Aid Compression. Closed captions are available on this video. If you are using a mobile phone, please enable captions clicking on the gear icon.
Support for the technology
“Frequency compression [lowering] is a nifty feature that few hearing aid wearers know exist,” says Dr. Steven Sederholm, a Boynton Beach, Florida audiologist who has severe hearing loss himself. “But it’s available in many hearing aids manufactured in the past ten years or so and has become really popular in the last year and a half. Resound, Phonak, Siemens, Starkey, Widex have it. Probably a few others.”
There are a lot of different names for it, frequency shifting, frequency compression, sound recover. Different companies have different ways to describe it. The technology is excellent for speech in noise, which is the biggest challenge most hearing aid wearers face, Many hearing aid wearers who could benefit from it don’t have it activated.
Steven Sederholm, Au.D.
“There are a lot of different names for it,” Senderholm continued, “frequency shifting, frequency compression, sound recover. Different companies have different ways to describe it. The technology is excellent for speech in noise, which is the biggest challenge most hearing aid wearers face, Many hearing aid wearers who could benefit from it don’t have it activated.”
Questions about effectiveness
Other audiologists aren’t quite as enthusiastic about frequency lowering. Joshua M. Alexander, an assistant professor of audiology at Purdue University in West Lafayette, Indiana, told Audiology Online: “…we don’t really know yet who will and who won’t benefit from this technology. Part of the reason is that there are only about a dozen peer-reviewed studies on modern frequency lowering techniques. Furthermore, there is a lack of consistency across studies, and sometimes within the same study, in terms of how the frequency lowering settings were chosen for each research subject.”
…we don’t really know yet who will and who won’t benefit from this technology […] there are only about a dozen peer-reviewed studies on modern frequency lowering techniques.
Joshua M. Alexander, Ph.D. in Audiology
Dr. Alexander explains that results can also vary depending on what criteria were used. “It can make a big difference if we are comparing detection of plural ‘s’ in a controlled laboratory experiment to ratings of perceived speech intelligibility in real-world environments.”
How does it work?
To understand frequency compression, you need to understand the basics of human hearing and hearing aid amplification. An infant’s ear can perceive frequencies ranging from 20 Hz (Hertz) to 20,000 Hz; the average adult human can hear sounds between 20 Hz and 16,000 Hz. As we age, we progressively lose our ability to hear high pitch sounds. A large percent of the speech sounds needed to understand communication, like the “f”, “s”, and “th” sounds, are at 3000 Hz and above, a portion of the pitch range often affected for those with aggressive hearing loss. Unfortunately, these high-frequency consonant sounds are also some of the softest of the average speech spectrum, which means a high amount of hearing aid gain is often needed to make them audible.
Hearing aid gain is the amount of amplification, or extra volume, applied to a specific speech sounds. Gain is crucial to making sounds audible at different pitches. Too much gain may cause feedback, those screeching sounds that drive hearing aid wearers crazy, and (as mentioned above) too much amplification can cause distortions inside the inner ear, leading to reduced speech clarity. This is where frequency compression becomes our friend. Rather than over-amplify those high-pitch speech sounds, we can bring them down into another pitch region, where they can be heard with less amplification (and distortion/feedback). The downside is that the sounds may not sound quite the same. There may be a mechanical or tinny quality. This tradeoff may, or may not, be worth it depending on the individual.
Who is a candidate for frequency compression?
Hearing aid manufacturers use an algorithm to figure out when to turn this feature on. They factor in the degree of overall high-frequency hearing loss and how much gain is prescribed for the high-frequency region. Prescribed gain provides a general guideline of whether it is possible to make a given signal audible using traditional amplification.
Who may NOT be a candidate?
- New hearing aid – New hearing aid users find it difficult to adjust to the frequency-lowered sounds. That’s why frequency compression isn’t usually automatically turned on in all hearing aids. Hearing aid wearers may need proactively ask their audiologist about frequency compression to find out if it would be recommended for them.
- People with mild to moderate loss – If you have a mild or moderate hearing aid in the high frequencies it’s not a great idea to turn on frequency compression. If you can still hear high pitch sounds, there is no reason to lower the pitch of any speech sounds. However, some people who are on the borderline may want to try it to see if it helps.
How do you know your frequency compression is working?
The best procedure to determine that the frequency compression program in your hearing aids is working effectively is real-ear testing, which uses a microphone probe to examine the signal reaching the ear canal. The audiologist should measure the amplified sound with the frequency compression turned on and off, and should confirm audibility for the “s” sound. If the frequency compression helps you hear softer high-pitch consonant sounds, it is probably worth activating permanently.
Hearing Aids with Frequency Compression
There are many choices for consumers looking for frequency compression (or frequency lowering) technology. Over the last few years, many of the manufacturers have added this feature to their main product offerings. See below for a list of the latest hearing aids on with frequency compression technology.
| Hearing Aid | Release Date | Price |
|---|---|---|
| Oticon Intent miniRITE R | 2024-02-11 | N/A |
| Jabra Select 300 Rechargeable | 2023-10-25 | N/A |
| Phonak Naída Lumity P-UP | 2023-08-09 | $2,190 |
| Audicus Omni 2 Rechargeable | 2023-08-01 | $2,798.0 |
| Unitron Moxi Vivante RT | 2023-05-02 | $3,064 |
| Starkey Genesis AI RIC RT | 2023-03-02 | $2,190 |
| Oticon Real miniRITE-T | 2023-02-22 | $2,682 |
| Philips HearLink 40 miniRITE T R | 2023-02-14 | $1,499.99 |
| Signia Styletto AX | 2022-09-06 | N/A |
| Oticon Own ITE HS | 2022-08-24 | $2,682 |
Ask your audiologist about frequency compression
You may need to ask your audiologist about frequency compression. “A lot of clinicians don’t like to turn on frequency compression because you’re taking high-frequency energy and not amplifying it—which is the usual way–but instead shifting it to another frequency–which goes against the grain for many audiologists.” Sederholm explains. “But it’s a fantastic technology that should be explained to hearing aid wearers and turned on if appropriate.” If you think frequency compression might help you, check with your audiologist. It might make all the difference.
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I am wearing new phonak audio m90 hearing aids. have severe hearing loss , hear about 30% +-. new phonaks, are using frequency shifting software. really lousy. buzzy etc.
audiologist says frequency shifting & amplification in lower frequencies a problem. My 30% hearing does not allow much room for shifting.
so question, any hearing aid makers that have better algorithims for handling frequency shifting, when wearer has 30%left of normal hearing/ (severe) ? perhaps another brand handles this problem better??
Does applying frequency compression without explanation or discussion by the audiologist mitigate the problems resulting from adjustments. Am I really making a mountain out of a routine molehill and should I remain confident to continue to use this retailer to sort things out?
More than a decade ago I was a customer to the newly opened [details deleted] I was seen by one of the partners in this new project and there was quite some difficulty in providing the correct hearing for profound ski slope speech frequency loss. It was important to avoid occlusion affecting the other frequencies that I enjoyed as a music lover.
My pair of Siemens behind the ear Signia Cellion (about my third private aid from [deleted] were purchased in 2017. They have provided excellent and reliable service with a couple of RICs being replaced under warranty.
Over the years I have given [deleted] five star reviews on Trustpilot. I am sad I cannot do so for this my most recent experience.
I had arranged an appointment to see the audiologist at [deleted] for both the private hearing aid and also for a pair of much larger Siemens Teneo hearing aids supplied under the NHS. I was given a 30 minute slot to be followed by an appointment with an optician.
Just over a week from the appointment I had what I thought was a failure of the RIC to the left ear and arranged to post both aids to [deleted] to deal with this and replace domes and filters. A star added for dealing with this in time for the appointment!
During this period I used the NHS aid and found it slightly better for speech but not so good against maintaining, at the same time, the quality of other sounds - for example classical music.
When asked I told the audiologist about my this experience and she adjusted the speech settings on both the private and NHS hearing aids. This was done from my level of understanding of her speech, behind a Covid mask, in the audiology room.
Wearing the Signia all seemed improved until we left the audiology room when there was violent feedback audible to those around me too. I joked that this was worse than leaving a garage and your serviced car backfiring!
Some adjustments were made and all seemed well for the rest of the day.
The next morning when I got into the car to drive there seemed to be feedback every time I moved my head. I could no longer hear the trafficator warning signal and some sounds were actually distorted.
Fortunately the NHS aid was functioning and so dealing with the Siemens has had to take second place to other issues.
Then I remembered I had a remote control for the Signia that had never been used as the previous automatic settings were perfect. Had the audiologist applied inappropriate overall settings instead of focussing increases on the speech frequencies? With a new battery installed I was able to turn down the preset opening volume to less than half. This has improved matters .
I know [deleted] read these Trustpilot reviews but a contact email address on the [deleted] website would be helpful to us both.
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Frequency shifting can help speech understanding if your esses and effs have gone out of reach. Very clever and good - I tried it. But the impact on music can be dire! All clogged up with muddled harmonics, was my experience.
But I have just read that the brilliant Dr Marshall Chasin and a colleague have trialled shifting down by one whole octave - never more nor less than that - so the shifted pitch remains 'in tune' with the unheard high musical harmonics that had provoked the issue. Apparently, the brain does get used to that.
I think it is, or will be, fitted to Widex aids - not available here in my local cash-starved UK national health clinic - but their musically-aware audio did fit me with an effective (ancient) pair of Phonak M70.