Tech Topic | June 2022 Hearing Review

By Amarilis Melendez, Masahito Kawamori, Lidia Best, Mark Laureyns

Great listening experiences don’t require throwing safe sound levels and your hearing health to the wind. Here is a review of the popular Apple AirPods Pro relative to WHO and ITU safe listening standards.

The World Health Organization (WHO) and the International Telecommunications Union (ITU) have created multiple standards with the objective “Make Listening Safe.” The standards already published are ITU H.870 Global standard for safe listening devices and systems,1 ITU H.871 Safe listening guidelines for personal sound amplifiers,2 and, recently, Safe listening in entertainment venues and events,3 along with the Be He@lthy, Be Mobile (BHBM) initiative using mobile technology to promote health, all available on the Internet.4 

One of the frequent objections for observing safe listening levels is that, to enjoy good sound quality, you need to be able to make the sound level of music very loud, or you will miss a good sound experience. This, of course, is antithetical to safe listening. The World Hearing Forum (WHF) is a global network of stakeholders promoting ear and hearing care worldwide. Members of this advocacy network are committed to facilitating implementation of World Health Assembly resolution WHA70.13 on Prevention of deafness and hearing loss5 and supporting Member States in this regard through alliance, advocacy, and action. 

The Make Listening Safe workgroup is one workgroup in the WHF committed to promoting the WHO safe listening initiative, with the goal of creating a world where nobody’s hearing is put in danger due to unsafe listening. One of the its primary objectives is convincing young people—the main target group—to change their behavior towards safe listening practices. However, we fully recognize the fact that, in order to succeed in this mission, our goals can’t spoil a great listening experience or hinder the enjoyment of good sound quality and music.

Since we have received many signals that the new Apple AirPods Pro are providing very good sound quality and include safe listening features and functionality in line with the WHO and ITU recommendations and standards, we decided to take a closer look.

We evaluated the new Apple AirPods Pro, with firmware version 4C165 on an iPhone with IOS (v15.3.1) in March 2022. In earlier Hearing Review publications by Nicky Chong-White, Brent Edwards, and their colleagues at the National Acoustic Laboratories (NAL) in Australia,6,7 we learned that Apple AirPods Pro can improve the signal-to-noise ratio when facing the talker (0° azimuth), and that the Headphone Accommodations feature has the potential to help people with hearing loss. The authors state that “Headphone Accommodations provides personalized, frequency-specific, level-dependent gain to make soft sounds audible in quiet environments for people with mild-to-moderate hearing loss without making loud sounds uncomfortable.”6

Customizing Apple AirPods Pro for Your Hearing

We followed the instructions of how to customize Apple AirPods Pro to your hearing as indicated in the instruction manual. These state that the best way to adjust the settings of Apple AirPods Pro to your hearing is to use the “Headphone Audio Configuration.” You are requested to do this in a quiet environment, and then listen for voices from the AirPods. If you reply “no” once to hearing voices, you get the message that “You’ve indicated that quiet speech is a little difficult to hear;” if you do this twice, you get the message “You’ve indicated that quiet speech is difficult to hear.”  At that point, you select your preference for a music sample in which soft sounds are boosted or standard. When that is done, you can choose the custom setting and go to a screen where you can “customize the transparency mode” with options to change the volume, the balance between right and left, the tonal tuning (darker or brighter), the level of ambient noise reduction, and the conversation booster.

We find that the fact that you can get the message that “speech is a little difficult or difficult to hear” is creating awareness that you may have a hearing problem­—a very important first step towards accepting the need to seek hearing care. Since, in the transparency mode, Apple AirPods Pro can provide gain for external sounds picked up by the microphones, they perform as a Personal Sound Amplification Product (PSAP).

Evaluation with Real-Ear Measurement

We evaluated the settings, gain, output, and other features using an Otometrics Aurical Freefit Real Ear Measurement on a 61-year-old adult (Figure 1). First, we selected the best-fitting earbuds with the “Ear Tip Fit Test” feature until we received the message that we had a “Good seal” on both-ears.


Figure 1. Set-up for the Otometrics Aurical Freefit Real Ear Measurement. Notice the picture in the middle, where the Apple AirPods Pro is in the ear, and the probe tube is in place and connected to the system.

We then performed the room and probe-tube calibration and the open-ear and occluded (AirPods Pro switched off in the ears) ear response. The open-ear resonance increased the signal energy up to 18 dB between 2000-4000 Hz. The occluded ear response attenuated the signal on average by 5 dB for the low frequencies and up to 25 dB for the high frequencies (2000-4000 Hz), which shows that the earbuds of the AirPods Pro provided a good seal of the ear canal (Figure 2).


Figure 2. Results of the Real Ear Measurement open-ear response (black curve) and the occluded-ear response (pink curve), for the right ear (left) and the left ear (right).

We manually set the AirPods Pro to the highest possible gain and checked the gain and output with real-ear measurement. The highest insertion gain (ie, the difference between the open-ear response and Air Pods Pro) was 23 dB at 3000 Hz for the left ear and the highest output was 103 dBSPL for 3000 Hz for the left ear. For the right ear, the highest insertion gain was 20 dB gain and 101 dBSPL output (Figure 3).


Figure 3. Results of the real-ear measurement insertion gain (3a right ear, 3c left ear) and the output response (3b right ear, 3d left ear). The input signals were ISTS (International Speech Test Signal) at 50 dBSPL (purple), 65 dBSPL (brown curve), 80 dBSPL (blue curve), and a pure-tone sweep at 90 dBSPL (green curve).

 These results are slightly higher, than in the Chong-White, et al article,6 which demonstrated a maximum gain on a 2cc coupler (Aurical HIT) test of 18 dB and a maximum output of 98 dBSPL. This difference can be explained by the fact that we measured in a real ear and they measured in a 2cc coupler.

How About the Ambient Noise Reduction in AirPods Pro?

We evaluated the impact of the Ambient Noise Reduction with the “Real Ear Noise Reduction” feature in the Freefit System, with both the noise and speech signal coming from the front. The difference between Ambient Noise Reduction switched on and off is up to 9 dB effective reduction of a “pink noise” signal (Figure 4). For a “speech ISTS” signal, the difference between Ambient Noise Reduction switched on and off is a maximum of 1 dB impact (Figure 5). We can conclude that the Ambient Noise Reduction is reducing noise and preserving speech.


Figure 4. Results of the Real Ear Noise Reduction Test for a pink noise signal; the green curve is the result for the Ambient Noise Reduction switched off, and the blue curve represents the Ambient Noise Reduction switched on. The left pane is the result for the right ear and the right pane is the result for the left ear.

Figure 5. Results of the Real Ear Noise Reduction Test for an ISTS (International Speech Test Signal) signal. The yellow curve is the result for the Ambient Noise Reduction switched off and the pink curve represents the Ambient Noise Reduction switched on. The left pane is the result for the right ear and the right pane is the result for the left ear.

The “Conversation Boost” feature is designed to activate a directional pattern to reduce speech signals from the rear and preserve speech signals from the front. This feature was not evaluated in this study, but was discussed in the Chong-White et al7 publication. For the Balanced Tone preset, they found that “the AirPods Pro with both CB-on and ANR-100% provides an SII-SNR advantage of almost 7 dB compared to not wearing any devices at all.”7

How About Safety and the Safe Listening Aspects of AirPods Pro?

The AirPod Pro volume indicator shows an orange icon when the output level is high while streaming music or other sounds, and this is fed into the information on your weekly and daily sound exposure in the iOS (15.3.1) Health app, as required in the (Figure 6) WHO/ITU H.870 standard Guideline for safe listening devices/systems and the ITU H.871 standard Safe listening guidelines for personal sound amplifiers.


Figure 6. On the left, the two ITU standards (H.871 and H.870);  in the middle, the indication that the sound is at a high (orange) or safe (green) level, on the right side; information on the weekly sound exposure, as required by the WHO/ITU safe listening standard.

The results lead us to conclude that AirPods Pro are exemplary in avoiding high gain and output levels and in embedding the WHO/ITU “Make Listening Safe” guidelines and standards.

What About the Sound Quality and Listening Experience of AirPods Pro?

When checking the reviews published on AirPods Pro, we see that nearly all the reviews are positive or very positive on both the sound quality and the noise canceling. Here is a sampling of the reviews:

Overall Conclusion

The AirPods Pro, with the latest firmware and iOS version, combine good sound quality, active noise reduction, and safe listening features currently available for users in line with WHO-ITU standards. The Headphone Audio Configuration feature has the potential to increase awareness for early signs of hearing loss. Overall, this proves it’s entirely possible for audio device manufacturers to deliver high sound quality, safe listening, and accessible hearing healthcare tracking features in their products.

Correspondence can be addressed to Mark Laureyns at: [email protected].

Citation for this article: Melendez A, Kawamori M, Best L, Laureyns M. Can you combine safe listening and sound quality? A look at Apple AirPods Pro. Hearing Review. 2022;29(6):26-29.

References

  1. International Telecommunications Union (ITU) website. H.870: Guidelines for safe listening devices/systems. https://www.itu.int/rec/T-REC-H.870.
  2. International Telecommunications Union (ITU) website. H.871: Safe listening guidelines for personal sound amplifiers. https://www.itu.int/rec/T-REC-H.871-201907-I. Published January 2020.
  3. World Health Organization (WHO) Safe Listening Devices and Systems: A WHO-ITU standard. https://apps.who.int/iris/rest/bitstreams/1176080/retrieve. Published 2019.
  4. World Health Organization (WHO)-Be He@lthy be mobile website. https://www.who.int/initiatives/behealthy.
  5. World Health Organization WHO programme for prevention of deafness and hearing loss: An outline. https://www3.paho.org/hq/index.php?option=com_docman&view=download&alias=42722-who-programme-for-prevention-deafness-hearing-loss-an-outline-722&category_slug=publications-pob-eye-care-9511&Itemid=270&lang=es.
  6. Chong-White N, Mejia J, Galloway J, Edwards B. Evaluating Apple AirPods Pro with headphone accommodations as hearing devices. Hearing Review. 2021;28(12)8-11.
  7. Chong-White N, Mejia J, Valderrama-Valenzuela JT, Edwards B. Evaluation of Apple AirPods Pro with conversation boost and ambient noise reduction for people with hearing loss in noisy environments. Hearing Review. 2022;29(4):24-27.
  8. Eadicicco L. I’ve been using Apple’s new AirPods Pro to see if they live up to the hype, and the verdict is a resounding yes–here’s why. Insider. http://www.businessinsider.com/apple-airpods-pro-review-sound-quality-noise-cancellation-2019-10. Published November 27, 2019.
  9. Bolton M. Apple AirPods Pro review. CB Creative Bloq. https://www.creativebloq.com/reviews/apple-airpods-pro. Published September 13, 2021.
  10. MacRumors blog staff. AirPods Pro. MacRumors. https://www.macrumors.com/roundup/airpods-pro. Published June 1, 2022.
  11. Molina A. Apple AirPods Pro review. SoundGuys. https://www.soundguys.com/apple-airpods-pro-review-27106. Published March 11, 2022.
  12. Beavis G. Apple AirPods Pro review. TechRadar. https://www.techradar.com/uk/reviews/apple-airpods-pro-review. Published April 8, 2022.
  13. What Hi-Fi? blog staff. Apple AirPods Pro review. What Hi-Fi? https://www.whathifi.com/reviews/apple-airpods-pro. Published March 9, 2022.