Mark using phone in kitchen

How Eargo mobile app communicates with your devices using ultra high-frequency commands




We get a lot of questions (and suggestions) regarding how some of our features in the Eargo Mobile App work. Our clients are savvy and brief answers tend to leave you with twice as many questions. It’s a complicated subject, but wonder no more!– I’m going to break it all down for you today. 

Human Hearing and Speech Sounds

Humans have the ability to hear frequencies from 20 Hertz (Hz) to 20KHz. Speech sounds mainly fall between 500 Hz and about 6kHz. This is the main reason we only test hearing from 250-8KHz and why hearing aids focus on amplifying speech sounds in this frequency range. (The other reason is limitations of speaker output capabilities in equipment and hearing aids, we’ll touch on this in the later sections.)

Extended High Frequencies (EHF) or Ultra High Frequencies (UHF)

We consider 9K-20KHz Extended High Frequencies (EHF) or Ultra High Frequencies (UHF). In this article (and in general) EHF and UHF are interchangeable.

Audiologists can test your ability to hear the extended high frequencies in a clinical environment with circumaural headphones (these are the big headphones that cover your entire ear and sit around it). Audiologists typically only test UHF when monitoring hearing thresholds for patients undergoing certain chemotherapies that are known to be toxic to hearing (called “ototoxic”), during some evaluations for tinnitus, and also may be tested evaluating difficulty with speech perception in noise with otherwise normal thresholds below 8K Hz. There is no well established normative thresholds for UHF for adults, but you can see from this article titled, Extended high-frequency audiometry in healthy adults with different age groups that over the age of 30 how well adults may hear UHFs varies and continues to decline with age. 

These transducers are susceptible to getting “knocked out of calibration” meaning, if they are dropped the professional should perform a biologic calibration test and if out of calibration have them professionally recalibrated back into specs before they can be used again. I like to mention this because we will circle back around about this fact later.


Ultrasonic refers to frequencies above 20kHz. Think– dog whistle. It seems silent to human ears, but sound pressure waves are occurring, we just don’t have the anatomy to be able to hear it like a dog has. Ultrasonic waves are also used for occupancy sensors in rooms. When there is a disruption in the ultrasonic wave emitted by the sensor, it knows someone is moving in the environment to turn the light on or sound an alarm, for example.

What’s My Point?

What does all of this have to do with your Eargo App, right? Our app uses ultra high frequency commands that your Eargo hearing aids “hear” allowing you to make desired changes. This is pretty cool because it works in a frequency range you and others next to you likely will not hear as you make an adjustment! 

Why Do It This Way?

Hearing aids can only be so smart. Hearing aids do not restore normal hearing and you are still hearing through a degraded auditory system. They are meant to pick up sounds around you and amplify them to overcome the amount of hearing loss you have so you get access to speech. This means they can also pick up extraneous, non-speech noise and speech from other people around you in those same frequencies. With Eargo’s Sound Adjust in Eargo 6, they switch automatically between settings best for loud noises and quiet. Sound Adjust activates when it detects you have gone from a quiet environment (like your quiet home) to a noisy one (like a loud restaurant), and vice versa. Challenging situations, challenging hearing loss, or even just a brain that is more fatigued and extra tired on any given day may still require additional adjustments to the programs.

Program and volume wheels, switches, buttons, and knobs on a hearing device have several downsides. They require space on and in the device which in turn requires the devices to be larger. Every time they are used they allow a little bit of debris on the unit or your finger to get inside of the device. This can lead to the breakdown of the device itself or at least the button, knob, or switch. They are not very easy to reach on completely in the canal (CIC) hearing device styles unless the backend of the device sticks out from your ear canal to be able to access it. These very tiny parts are hard to feel to activate if you have neuropathy or any numbness in your fingers. Lastly, there are only so many things you can make one button, switch or knob do, so you’re limited to the changes you might have access to.

To change your hearing device without a button, switch, or knob requires some kind of remote. If the remote uses a Radio Frequency (RF), this requires an antenna receiver in the hearing aid to receive the radiofrequency. Frequency Modulation (FM) systems require a loop system (a physical loop worn around the neck) to communicate from the remote to the device and the device requires a telecoil inside or a remote to a receiver in the device or boot attachment on the outside of the device. All of these impact the size of the device as well as expected battery life.

Traditionally, people do not want to carry a remote around, so manufacturers have found various ways to utilize mobile phone applications instead. One way to do this is via Bluetooth. Bluetooth in your mobile phone paired to a Bluetooth receiver in the hearing aid. If you’ve read my blog comparing hearing aid styles, you’ll remember Bluetooth receivers (like tecoils and antennas) can greatly impact the size of the device. Even if the device’s size can accommodate a Bluetooth receiver, they require a lot of battery power and will significantly reduce your hearing device’s battery life. The size of the device is impacted to accommodate the larger battery required.

At Eargo, we keep our devices as small as we can produce them while creating solutions to offer features that have minimal impact to the battery size and daily battery life. We utilize UHF technology in our Eargo 5 and Eargo 6 product models with the Eargo mobile app. 

We do have a Bluetooth receiver in the Eargo Charger that communicates to and from your phone’s Bluetooth for the following Eargo Mobile App features:

  • Initial pairing of the Eargo Mobile App to your Eargo system
  • At the completion of Sound Match
  • To receive software/firmware updates from your app into your devices
  • Using “Program Sync” or “Revert to Factory Presents” features in your Mobile App’s Menu under “Devices”

Here’s the details in layman’s terms: You touch a selection on your Eargo Mobile App screen. This tells your phone speaker to play a specific UHF tone associated with the command that was pressed. This UHF tone that comes out of your phone’s speaker is a sound pressure wave (meaning, it moves air particles). This reaches the level of the ear where your Eargo sits. Eargo’s microphone receives this UHF sound wave. Your Eargo will make the necessary change associated with the specific tone it received.

Consider the following:

Remember we discussed audiologists use circumaural headphones to test ultra-high frequencies? This is the only job of these headphones, they aren’t mobile phones that have to also make phone calls, text messages, have cameras, access the internet, etc….yet, headphones have to be calibrated annually to stay in the specification and can become uncalibrated rather easily. This means phones, with all the different models and components, can vary greatly and their ability to effectively produce UHF. The location of speakers producing the UHF also varies across phone models adding a layer of complexity. What About Those Speaker Specs? is a good article explaining all the nuances to consider for stand-alone audio speakers, much of which can be applied to understanding mobile phone speakers. Mobile phone speakers may not stay within certain output specifications, phones get dropped, and we don’t have phone speakers calibrated…all of this results in a lot of variabilities. The Eargo Mobile App has to know how to play nice with as many phone models as possible. 

Operating System updates to your phone can also have unintended consequences to any of your phone’s mobile apps– ours included. If this seems to have occurred, it may be beneficial to delete the Eargo Mobile App, forget your Eargo Charger from your list of paired Bluetooth devices in your phone’s Bluetooth settings. Redownload the app and pair your Eargo system again. 

Check certain sound features enabled on your phone. The following suggestions can vary from phone brand and model, but worth checking if you’re experiencing an issue. Make sure you don’t have your sound switched off or your phone in a Do Not Disturb mode that is preventing the output of your phone’s audio sounds. If you have an Android phone and “Touch Interactions” enabled, this means you have a feature enabled that your phone will make a sound when you touch your screen, so your speaker can’t properly produce the UHF output at the same time. Instead, disable this feature. On Apple devices, disable the “Change With Buttons” feature in Sounds and Haptics of your phone’s settings. Check your phone’s audio routing. Were you just playing music connected to a Bluetooth speaker? The audio may still be routed to that device instead of through your phone to get to your Eargos. Are you on a phone call?– It will not work because your phone’s audio is already being utilized for the call and this will take precedence over audio from an app, including UHF commands. 

Make sure your phone’s speaker is not clogged so the volume can come out. Brush it vigorously with a clean dry toothbrush. Check your phone’s speaker’s volume. If it’s too low the sound wave is not loud enough to make it to your ears.

Hold the phone as suggested so the speaker sound is towards both of your ears. If you turn your head or have your phone off to the side and not straight in front of you, it creates what’s called the “head shadow effect.” It’s just like it sounds, your head can actually absorb the sound before it can make it around the head to still be loud enough to get to the ear and activate the Eargo microphone. 

Make sure your Eargo’s microphone is not compromised. If the hearing device’s microphone is clogged it can’t receive the UHF command. Brush out your hearing device’s microphone. Twist the mic cap back and forth, brush all around the edges of the cap. If this still does not work, remove your mic cap, brush around your Eargo sound inlet, and put on a new mic cap. Check placement in your ears, if it is in too far your ear canal skin may be relaxing on the openings of the microphone cap. Try changing the position and depth of it in your ear canal to find a spot that optimizes use with the UHF remote features.

Go to an environment with less noise to make necessary changes. If you are trying to make a temporary adjustment on your Volume or Noise Filter while at a loud gathering, concert, or noisy restaurant the Eargo microphone may not be able to pick up the UHF command through the noise. Eargo’s Research & Development is constantly working on improving the reliability of these UHF commands in noisy environments. Excuse yourself to the bathroom, a more quiet room, or make a few adjustments when you get there before you get out of your car. Try moving your phone closer to your face so the UHF command has a better chance of getting to your Eargos. 

To change your programs in these environments, don’t forget you can double-tap the backend of your Eargo to advance through each program. 

Only perform Sound Match in a quiet environment so you can listen carefully to hear the soft sounds played without interference from noise in the environment. If you are experiencing a message prior to starting Sound Match indicating your environment is not quiet enough, this is where “Touch Interactions” on Androids can create this “noise” interruption. Disable this in your settings as previously mentioned and you should be able to advance past the Noise Check screen to begin Sound Match.

Why Don’t I See This Change in My Eargo Mobile App? 

These commands are outbound commands only. Remember, to keep the devices small and maintain the battery life there is nothing in the hearing devices to communicate back to the app. Eargo devices are not communicating with your Eargo Mobile App.

Due to the nature of the outbound signal variability as described so far, the app does not reflect a change on the screen just because you pressed the button. For example, let’s say your head is turned and you are in a noisy environment and you press the plus symbol (+) on your volume screen 2 times. Perhaps your right device never changed at all and your left one only changed once – your app doesn’t know this to reflect your current device settings in the Mobile app. 

Changes in your Eargo app that use the UHF technology: 

  • Sound Match (In your Eargo Mobile App Menu)
  • Volume Screen to make temporary changes: 
    • +, -, and mute
  • Noise Filter Screen to make a temporary change: 
    • High, Medium, Low, Off
  • Programs:
    • 1-4 Programs you have enabled (or our Manufacturer Factory Presets 1-4 if you have not performed Sound Match)
    • Sound Tuning to make a lasting change to a program:
      • Volume – or +
      • Treble – or +
      • Bass – or +

Sound Match:

Sound Match uses UHF commands. When you first start Sound Match the screen will prompt you to increase your phone volume to the proper loudness before you can advance. When you click “I Am Ready” on the next screen, make sure your phone is held in front of your face as previously discussed because this screen will play the first UHF command to put your devices in Sound Match mode. The screen prompt will ask you to verify if you heard the word “Mute.” Make sure that you heard it said in each device. If you’re not sure, press “No” at the bottom so it can send the UHF command again to your devices while holding your device as previously specified. If you select “Yes” and only one device (or no devices) are in Sound Match Mode you will not hear the tones/beeps played through your Eargo devices as you begin listening for the sounds on the next screens. If this happens, that’s ok, just tap “EXIT” in the top right to stop Sound Match. I advise taking out both devices and placing them in your charger (this will take them out of Sound Match mode, turn off the devices, and restart them when you take them out of the Eargo Charger). Check the troubleshooting suggestions as listed in this blog, then start Sound Match again from the beginning with all of these points in mind again. 

While performing Sound Match it plays a UHF command to your Eargo devices to tell your Eargo speaker to play the next specific frequency tone/beep at various loudness levels, so make sure to keep your phone at the appropriate angle and distance in front of you until completed. Once you have completed Sound Match for the left ear and then the right ear, it will prompt you to place your devices into your Eargo Charger to update these results into your Eargo device’s programs– Follow the prompts on your phone.

Volume and Noise Filter Screen (Temporary Changes):

Make temporary changes via UHF by touching selections on your Volume and Noise Filter screens. If the command was received your hearing device will play a double beep indicator (a little jingle) each time so you know if it was received. If you only heard the double beep indicator in one ear, tap on the right/left hearing device shown as an image at the top of the Volume Screen, to change the Volume of just one device at a time. If at any time you want to go back to each program’s default setting, just switch to a different program and your programs will go back to default Volume and or Noise Filter settings. 

Your Eargo Hearing Devices have maximum and minimum volume settings. You may increase or decrease the volume 2 steps up or 2 steps down on any of your listening programs. Continuing to tap on the + or – buttons beyond the 2 step limit won’t result in an additional volume change even though you may still hear the double beep indicator in your devices. 

If you still feel you need more or less volume, consider making persistent adjustments to Bass and Treble from Sound Tuning. 

Sound Tuning (Applying a Persistent Change to a Program):

If you want to make a permanent change to a program so every time you select that program it has your preferred adjustments saved so you can make fewer temporary changes:

  • On your Programs screen: Click the pencil icon to edit. 
  • Tap on the upper right corner of the program you want to make a lasting change. 
  • As you make changes to volume, treble, and bass remember all the techniques we discussed here for the UHF command to be received by your Eargos each time you press a command.
  • If you want the adjustment for right/left only, simply tap on the device at the top of the screen so it’s highlighted before you make the adjustment.
  • Select “Done” in the upper right corner.
  • Make adjustments to any other programs, then select “Done” on the bottom of your Program screen when finished.

If you need additional assistance or have more questions? Give us a call at 1 (800) 903-6883 for one-on-one help with our licensed professionals or mobile app specialists.