Best Ways to Hear Better in Noise


Noisy-restaurants

Hearing loss results in two main problems; loss of audibility and loss of clarity in noise.

Loss of Audibility. This means that sounds are too soft to hear.  We have a couple of strategies to make sounds more audible.

    1. Amplification. Today’s modern hearing aids selectively make softer sounds louder than louder sounds.
    2. Frequency Compression.  In some hearing aids such as the ones provided by my company, Phonak, the hearing aid can shift high pitched sounds down to lower pitches.  The logic is that you may have too much damage in the high pitches to amplify the sounds sufficiently, so we will shift these sounds to regions where you have better hearing.
    3. Cochlear Implants.  If high powered hearing aids equipped with frequency compression no longer helps you hear, we now turn to a Cochlear Implant to make sound audible.  See these links for more information of Cochlear Implants.  Also here.

Loss of Clarity in Noise.  I wish that hearing loss was merely a problem of loss of audibility.  It would be so much easier just to amplify the sounds and be done with it.  Just like wearing a pair of corrective lenses for vision, right?  Wrong.

After we do our best to make sound audible, we also have to do something about getting rid of the background noise.  As one’s hearing loss gets worse, not only do we need stronger and stronger hearing aids, but we also need to get rid of more and more noise.  For example, a person with normal hearing can handle a signal-to-noise (SNR) ratio of 0 and still understand most of what is being said.  An SNR of 0 means that the person talking to you is the same loudness as the person you don’t want to listen to.  This happens all the time.  Imagine a restaurant.  There are people all around you talking at the same loudness as your significant other across from you.  You normal hearing folks can handle this, people with hearing loss cannot.

Strategies to Hear Better in Noise.

  • Ear Level Directional Microphone Technology
  • Remote Bluetooth Microphones
  • Fixed Gain FM/Infra-Red/Digital Technology
  • Dynamic FM

These 4 strategies are not all the same.  They vary significantly in the amount of noise reduction provided.

Directional Microphones:

A directional microphone works by picking up the sound from one direction (typically the front) but not from anywhere else.  So now you won’t hear the annoying kid in the restaurant behind you as much.  Independent research has shown that a directional microphone on the hearing aid does help you hear better in noise compared to a regular omni directional microphone. The range of improvement found in these studies is anywhere from 3 to 8 dB.  So it gets rid of about 5 dB of noise.  This is not huge, but for people with milder losses of hearing, this may be all they need.  It certainly is convenient.  You don’t need to carry extra equipment.  In fact, in today’s modern hearing aids such as Phonak Bolero Q or Virto Q, these microphones get switched on automatically when it gets noisy.  Pretty awesome technology in there.

Remote Bluetooth Microphones.

Many companies, including the one I work for, now have affordable Bluetooth microphones that can be used with your hearing aids.  You clip this microphone onto the person you want to hear and it transmits wireless via Bluetooth radio waves to a device around your neck which in turn sends it to your hearing aids.  By moving a microphone from the ear level to a much closer proximity to the talker’s mouth, we can achieve much higher signal-to-noise ratios than a directional microphone located on your head.  Here is the example from Phonak which involves the use of the Remote Microphone in conjunction with either a ComPilot or an iCom.

Phonak Remote Mic

The advantage of Bluetooth microphones are that you get rid of more noise compared to ear level directional microphones.  They are convenient, and easy to use with simple and intuitive controls (just an on/off switch and volume).  Finally they have the advantage of low cost.  It is a very affordable solution, much less than FM.

Traditional and Fixed Gain Wireless Systems

To achieve an improvement in SNR up from a Bluetooth Microphone system would be to use a fixed gain wireless system. Examples of include:

  • Phonak’s 2nd Generation systems such as Campus, SmartLink SX, ZoomLink, EasyLink (silver casing)
  • Oticon Amigo
  • Comfort Audio Digisystem

These are all examples of fixed gain systems and achieve similar results.  The reason these perform a bit better than the Bluetooth microphones is that most incorporate directional microphones on the transmitters and therefore can get rid of more noise.  Additional benefits include greater operating ranges and longer battery life.  However, cost is significantly higher for what is really just a modest improvement over a lower cost Bluetooth microphone system.

Adaptive Wireless Systems

Some wireless systems are adaptive.  For example, the Dynamic FM technology that Phonak uses is different than fixed gain systems in that it adjusts the FM gain depending on the environmental noise level.  Therefore additional gain is added if the background noise level increases.  The technology works by measuring the ambient noise levels in the room during speech pauses.  If the ambient noise level rises to over 57 dB SPL, a command is sent from the transmitter to the Dynamic FM receivers to increase the FM gain.  When the FM gain increases, you get a higher signal to noise ratio.  It is still comfortable to listen to because today’s modern hearing aids all have compression which keeps this at a comfortable level.  Examples of Adaptive Wireless Systems include Phonak inspiro, SmartLink+, ZoomLink+, EasyLink+ and any 3rd generation Phonak receiver (eg MLxi, ML9i to ML16i)

ZoomLink+ with Dynamic FM

How Do These Technologies Compare?

1. Directional Microphones vs Fixed Gain FM.  This classic study by Valente et al in 2002 compares an omni mic to a directional mic on a hearing aid which in turn compares this to an FM system.  The data is backwards, so the lower the number, the better the result.  It is very powerful data showing how well an FM system can help over just an ear level directional microphone.

Valente et al 2002

2. Fixed Gain vs Adaptive Gain Wireless Systems.

The most extensive study comparing fixed gain vs adaptive gain wireless systems was conducted by  Dr. Linda Thibodeau, PhD, University of Texas at Dallas, USA, and the Callier Centre for Communication Disorders, Dallas.  AFMA refers to the Adaptive Gain FM while Fixed of course refers to fixed gain wireless less.  Remember that fixed gain wireless systems include Bluetooth microphones, Phonak’s second generation FM (Campus), Oticon Amigo, and Comfort Audio DigiSystem to name a few.  As you can see, when the room noise gets louder, the word recognition score for the adaptive gain wireless system is much higher.  In this example, the transmitter used was the Phonak inspiro with Dynamic FM.

Results of Dynamic FM over traditional

3. Adaptive FM vs Digital Wireless.

This study, conducted at the University of Orebro in Sweden, compared a digital wireless system with fixed gain (Comfort Audio Digisystem) to a adaptive gain FM system (Phonak Dynamic FM).  The question is what leads to better performance in noise.  The result s clearly showed that the adaptive gain system (Phonak Dynamic FM) leads to better performance.

Dynamic vs Digital

So which do you need?

I will make my next blog post on how to select the correct technology for your needs.  But here are the summary points.

  1. You need technology that helps you not only hear soft sounds, but also helps get rid of background noise.
  2. Directional microphones on the hearing aid itself can get rid of about 5 dB of noise.
  3. Bluetooth microphones provide additional improvement in noise.
  4. Fixed gain wireless systems such Phonak’s second generation FM, Oticon Amigo and Comfort Audio Digisystem provide additional improvements over a Bluetooth microphone, but these may be modest improvements.
  5. Adaptive gain wireless systems such as Phonak Dynamic FM still provides the largest amount of noise reduction.
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16 thoughts on “Best Ways to Hear Better in Noise

  1. Thanks for this informative post. I am in the process of finding a streamer for my Oticon Agil pro aids to use with my cell phone. I am in the moderate/sever range in both ears and slowly progressive to the point I need adjustment about every eight months. Worse on the high end freq. range so woman’s voices are a problem and if there is any background noise at all I am out of the game. When an important call comes in trying to find a quiet room or somewhere quiet to hide and pulling over when driving and shutting down the vehicle is getting old. I will be looking forward to your future posts.

    Thanks, Terptube

  2. My personal experience with hearing aids is that they are designed to separate the deaf person from his money. I have 2; a Phonak and a Siemens. Both have a terrible signal to noise ratio. They reside in my bureau drawer. Whenever i complain to an audiologist, the answer seems to be, ” you should try our latest model” (at a higher price) I wouldn’t mind paying a higher price if it returned value, but I haven’t found it yet and all the audiologists I talk to seem to act like used-car salesmen. The profession, as presently constituted, does not rate the label of “doctor”.

    • Hi John,

      Those are strong criticisms about both hearing aids and audiologists, but I feel you have a right to express your feelings. You mention hearing too much noise, but now we must ask the question is what is the correct technology for you? Do you need directional mics? a Bluetooth Remote Mic? An FM system? Which kind of FM transmitter? Interestingly, the most expensive hearing aid does not necessarily solve your problems. Some folks do better with an standard kind of hearing aod combined with an FM system. I suggest you find an audiologist that feel is reputable and can trust, and tell him or her that you are open to explore all possibilities for improving the signal to noise ratio.

      • Thanks, Peter. That is a sound suggestion. (pun intended) The problem is to identify an audiologist I can trust. The one who sold me the two aids I own was referred to me by my ENT doctor only after I suggested I was willing to spend whatever it took to improve my hearing. (In other words it wasn’t an enthusiastic referral.) The second aid was purchased after I had an attack of “sudden deafness” in my “good” ear. Even though much hearing has returned, my barbershop quartet asked me to resign because I couldn’t make sufficient pitch differentiation. Now the pianist at the assisted living center where I conduct singalongs claims I sometimes sing in several different keys. I really need some system to help me wander among the patients while still hearing the piano.

      • Hi John. Keeping pitch is the hardest thing to do with a hearing loss. Studies show we can certainly maintain rhythm for sure, loudness somewhat. But the loss of frequency resolution is the hardest to correct. This is why I use an electronic tuner and play a fretted, rather than a fretless bass.

        Do you sing with a PA system and microphones? If yes, then you could try what I do. Basically, I use one of the monitor (or auxiliary) outputs. I mix this to my own needs, the audience does not hear it. Then it goes into a compressor to even out the loudness, and finally into the FM transmitter. This then gets transmitted to my wireless receivers. Perhaps this may work for you?

      • That may help. Unfortunately, what you say sound all Greek to me. I’m a nerd when it comes to audio equipment. We don’t use any amp for these groups. How would I start?
        (in layman’s language. I can’t understand all that techno stuff.)

      • Basically, you want 4 mics, a mixing board, and an FM system attached to the headphone jack of the mixing board. I actually posted about this before. Start reading after this quote “But wait, we are not done yet!  I also need to hear the rest of the band correct?” The post is called Listen to the Music Live…

  3. Pingback: How Do You Know You Need a Wireless Microphone? | Deafened But Not Silent.

  4. Another way of providing improved listening in noise is to use assistive listening technology with highly directional microphones, or headworn, close-talking boom microphones close to the speaker’s mouth. (Personal assistive listening technology such as wireless RF systems or less expensive handheld amplifiers can be used with them.) The headworn boom microphones are used by many professional singers (such as the singers in the first production of “Celtic Woman”) and would reject a great deal of noise. My guess is that using such microphones would provide a superior SNR compared to an approach that would amplify background noise along with the speaker’s voice. Reducing or eliminating background noise will improve the signal to noise ratio better than amplifying a signal that was already at a comfortable listening level.

    The separate microphones that are designed to reject noise can be surprisingly effective, and are often more effective than the microphones built into many kinds of assistive listening technology, particularly in extremely noisy situations like parties, bars and restaurants. Using such microphones, I long ago learned to maximize the use of my own assistive listening technology by using the lowest level of gain possible; this improves the SNR by avoiding the undesirable amplification of the background noise.

    Unfortunately, it can be difficult for consumers to learn about all the different kinds of assistive listening technology and microphones that are available. One way can be to join the national organizations of people with hearing loss and/or attend their national or regional conventions or conferences. The Hearing Loss Association of America is having its national convention in Portland, Oregon, from June 27th to June 30th, and typically has a very large exhibit hall where attendees can view and try out many different kinds of hearing assistive technology, including a wide variety of assistive listening technology. HLAA (formerly SHHH) is how I myself learned about the majority of available hearing assistive technology.

      • This is a perfect example of what I talking about. People in this group talk about certain technology as if everyone knows what they are talking about. The truth is that only a small group of cognicenti understand. The rest of us are left in the dark. Or we go to a supposed expert and all he does is try to sell us some overpriced hearing aid that doesn’t really help.

      • Hi John. I try to write my blog with the regular person with hearing loss in mind, but it is also read by other Hearing Care Professionals. These comments are an example of an exchange between the latter, therefore it took on a more technical tone. However, I do hope you find the actual blog posting helpful. Please note, that I am not of the belief that the most expensive hearing aid is necessarily the best one, and I have stated so in my blog.

      • Thanks, Peter. I appreciate your reply. I just wish I could find a good specialist locally who felt the same.

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