The objective of headphones with adaptive transparency mode / adaptive awareness mode is to allow you to hear your surroundings as you would without headphones while at the same time reducing loud noises.
Wouldn’t that be great?
Walking around town and being aware of traffic but not stressed out by excessive honking, sirens, loud motorbikes, and shouting.
This is how adaptive transparency works in a nutshell
Your headphones isolate you from the noise in your environment via well-sealing ear tips (or ear cups in the case of over-ear headphones).
To let you hear in a controlled way, the headphones electronically pick up environmental sound via external microphones and reproduce it via their speakers, but limit the maximum output of the speakers to a certain sound level (limit).
As long as environmental noise doesn’t exceed the limit, you hear everything at a normal volume.
But as the noise level approaches the limit, the headphones reduce the volume of everything you hear to keep the output below the limit.
To help with noise sensitivities, the limit needs to be low enough so that most noises that bother you are in fact being reduced but not so low that volume changes become a nuisance all by themselves.
OK, let’s see how this works in specific implementations.
I have recently tested two earbuds with adaptive transparency mode, Apple’s AirPods Pro 2 and Bose’s QuietComfort earbuds II.
I also use several electronic hearing protection headsets that have an adaptive transparency mode (aka level-dependent hearing).
Adaptive transparency on the AirPods Pro 2
Here is a specific case illustrating how this works on the AirPods Pro 2:
I was wearing the Pro 2 in adaptive transparency mode and talking to a friend along a road with moderate traffic. I could hear my friend and the traffic at a normal volume (excellent sound fidelity, IMO). Then we passed by a construction site where a worker was cutting stone using an angle grinder.
As we got close to the worker, the noise level increased until the Pro 2 started reducing the gain of the microphones and thus the volume of the grinder piped in via the speakers. My friend’s voice and the traffic noise were also being reduced.
As we got further away from the grinder, the mikes’ gain increased and I could hear my environment again at a normal volume.
In general, the adaptive transparency mode on the Pro 2 worked quite well to take the edge off of very loud noises.
I couldn’t find a statement by Apple stating the exact limit for these earbuds; however, in my tests with continuous noise, the limit for the Pro 2 appeared to be at around 85 decibels (perhaps a bit lower).
In the example above, the grinder noise level was about 90 decibels at a distance of 5 feet (NIOSH sound level meter).
How often does this help to reduce stress from excessive noise?
To help against the noises you may be sensitive to, the limit must be low enough so that noises you find too loud are in fact being reduced.
And for me, the Pro 2’s limit is a bit high for stress reduction.
I find traffic noise at 75 decibels (which is what you can get quite often on a busy road) already loud.
At that noise level, however, these earbuds don’t reduce the transparency mode volume, or at least not noticeably for me.
So while the Pro 2 helped against very loud noises (the grinder or siren at close distance), many merely loud noises I would like to reduce are not affected (e.g., shouting) or affected too late (approaching motorbike).
As a consequence, I often use them in noise cancelling mode amidst traffic noise, which is very effective but reduces situational awareness. At times, off-mode is a good compromise.
Adaptive transparency on the QuietComfort earbuds II
The Bose QuietComfort earbuds II (review and detailed test) are another pair of earbuds with adaptive transparency.
Their transparency mode is called “Aware” and includes an adaptive feature called “ActiveSense.”
In my tests, ActiveSense’s limit was substantially lower than that of the Pro 2, closer to 70 decibels, i.e., noises in excess of 70 decibels are being reduced.
So how much does this lower limit help to reduce stress from excessive noise?
ActiveSense often kicks in amidst traffic (e.g. approaching motorbike, truck, screeching, someone shouting next to me, or even me shouting) and makes city environments noticeably quieter.
Comparing the 70 and 85 decibel limits directly, personally I find the lower limit to be more helpful for reducing stress due to loud noises. A 85-decibel limit may help to protect hearing but “loud” begins at a much lower level.
Moreover, the QC earbuds II not only adjust the microphone gain/volume (which works against mid and high frequency sounds).
With ActiveSense enabled, they even deploy adaptive active noise cancellation in transparency mode to reduce excessive lower frequency sounds (e.g., big bike) and lower mid frequency sounds (e.g., hand dryers in public restrooms) that are not that well reduced passively (i.e., by the ear tips alone).
The potential noise reduction (adaptability) provided by doing both progressively reducing the microphone input and actively cancelling noise can be stronger and broader, which makes it easier to defend a lower noise limit in transparency mode.
The side effects of a 70-decibel limit and adding adaptive noise cancellation
With a 70 decibel limit, many loud environmental noises will cause a volume reduction, which is good if they bother you.
However, if the environmental noise level varies a lot and you don’t perceive the noises as stressful, the ongoing transparency mode volume adjustments (due to the lower limit) might trouble you instead.
In addition, if you are sensitive to adaptive noise cancellation, you might find the noise cancellation changes in response to large environmental noise level changes unpleasant.
I am generally happy with the way ActiveSense works and have it on most of the time when I am in transparency mode.
But there are times when it bothers me (e.g., loud marketing events at a shopping center).
When ActiveSense messes with the environmental volume too much for my taste, I switch to a light noise cancelling mode, which I have defined as a preset, accessible via a long-tap on the earbuds.
For more on this, read my test of the QC earbuds II.
That way, I retain more situational awareness than with full-on noise cancellation but still have a predictable reduction of aggravating sounds.
All in all, the QC earbuds work very well as noise sensitivity earplugs.
Adjustable transparency or adjustable noise cancellation as an alternative
Headphones that allow you to reduce the transparency mode volume can be a good alternative to adaptive transparency for noise sensitivities.
While you get somewhat worse situational awareness, you gain a predictable, adjustable volume reduction of stressful noise.
Many noise sensitive people wear light earplugs that achieve something similar: they reduce environmental sounds by a moderate amount, e.g., 15 decibels.
With suitable headphones, you get an advantage though: the level of noise reduction/transparency can be tweaked to suit your personal requirements.
In some headphones, such as the QC earbuds, this can be achieved by adjusting the noise cancellation strength (full ANC and full transparency are the two ends of the slider). This works very well for me.
Other earbuds/headphones may have a separate slider in the app for adjusting transparency mode volume.
So if you have headphones with a good transparency mode and a volume slider, give that a try.
In principle, there is also a custom (adjustable) transparency feature in iOS. In my tests, however, this made the AirPods’ transparency mode sound unnatural and processed, to the point of me not wanting to use the feature at all.
This is a pity; the sound quality of the standard and adaptive transparency modes of the Pro 2 is excellent. Perhaps future updates can bring the custom mode to the same level.
If you want to give adjustable transparency mode on the AirPods a try:
In iOS, under Setttings->AirPods Pro->Accessibility->Audio Accessibility Settings->Headphone Accommodations (Apply With), you can enable custom transparency mode and play with the sliders.
Using adaptive transparency to protect your hearing at the concert or workshop?
In principle, adaptive transparency mode, i.e., limiting the maximum output in response to loud noise coming in via the microphones, could help to protect hearing.
In fact, electronic hearing protection headsets, such as 3M’s Pro-Protect, with adaptive transparency mode are readily available.
Why not instead wear the above-mentioned earbuds when running loud power tools, riding a gas-powered lawn mower, or attending a concert?
Well, the electronics may limit the sound coming in via the headphones’ speakers to 85 or 82 decibels, but the maximum amount of noise reduction is still limited by the isolation the ear tips/ear cups provide.
Some people are promoting the idea of using the adaptive transparency mode of the AirPods Pro 2 at concerts. I understand they like the sound fidelity, but you would have no performance guarantee whatsoever:
I haven’t seen any official statements as to how much noise reduction you can expect.
And, neither the Pro 2 nor the QuietComfort earbuds have a noise reduction rating (as you would get with hearing protection headsets or earplugs).
In the case of the Pro 2, the high frequency noise reduction the ear tips offered in my ears was only modest. At some frequencies, I was only getting around 10 decibels. Perhaps you would get more, perhaps even less.
So for attending a concert, I would use well-fitting earplugs. And if the concert is very loud, I would lean towards plugs with a high noise reduction rating rather than Hi-Fi earplugs. (See link above for ideas.)
How about working in a loud workshop or doing landscaping work?
You may be thinking, “I will switch to active noise cancellation when I use power tools, leaf blowers, or lawn mowers.”
In my experience, the ANC of the Pro 2 can indeed reduce many lower frequency machine noises quite effectively, so one could be tempted.
But, for the higher frequencies (where the ANC doesn’t work), you would again rely exclusively on the seal of the ear tips and the very modest noise reduction. What’s more, you particularly need to protect your hearing at these frequencies to maintain your ability to understand speech.
Would the QuietComfort earbuds fare better at the workshop?
In my ears, Bose’s ear tips offered significantly better passive noise isolation than the ones of the Pro 2.
And Bose has added adaptive noise cancellation to their adaptive transparency mode (= Aware with ActiveSense enabled).
Indeed, even in adaptive transparency mode, their tech does make a gas-powered lawn mower (and many other machines) a lot quieter.
But, Bose doesn’t give any guarantees for their earbuds either, neither with respect to the passive noise reduction nor the capabilities of the active noise cancellation. So I can’t recommend using these as a hearing protector at the workshop. I wish they’d go into that market.
Hearing protection headsets with adaptive transparency mode
If you want headphones with adaptive transparency to protect your hearing in an occupational setting while maintaining situational awareness, use electronic hearing protection headsets with a suitable noise reduction rating.
The adaptive transparency mode limit for both of these headsets is 82 decibels, which is set at that level for hearing protection (rather than stress reduction). In addition, they allow the user to adjust the transparency mode volume, so you have control over how loud you hear your environment.
They may not sound as good as noise cancelling earbuds, but better safe than sorry.