In this post, I am reporting on my noise reduction test results for two top active noise cancelling headphones (ANC headphones) when worn over foam earplugs.
If you are bothered by environmental noise but your headphones (or earplugs) alone don’t block enough noise, this post is for you.
I often wear noise cancelling headphones together with earplugs when I want to sleep on a plane, in particular if a baby starts crying in close proximity.
I have also found this combination to be among the most effective snore blockers.
Additionally, you could use earplugs underneath your headphones as a “secret weapon” to further subdue loud chatter in an office when you don’t want to listen to music.
But how effective is the combination of ANC headphones and earplugs really when compared to headphones or earplugs alone?
And, how does the earplug fit affect the noise reduction?
Here are the models used in this test:
- ANC headphones: Bose QC35 and Sony WH-1000XM4
- Foam earplugs: Hearos Pretty in Pink (NRR 32)
- This post is meant to help with noise annoyance reduction in daily life.
- Consumer noise cancelling headphones have no noise reduction rating (NRR) and are not marketed as hearing protectors. If you want to double-up for improved hearing protection, use earmuffs with an NRR.
Brief summary of my results
ANC headphones and foam earplugs together are a lot more effective than either of the two alone at reducing noise.
For me, noise reduction in the tested frequency range (40 to 8000 Hz) mostly exceeded 40 decibels and for mid frequency noise from 160 to 1000 Hz even 50 decibels.
In a word, you can expect substantial benefits against low, mid, and high frequency noise.
Moreover, because the headphones used in this test exert a much lower headband force than earmuffs, I find this combination more comfy (in particular for sleeping) than wearing earmuffs over earplugs.
Surprisingly, with well-fitted earplugs underneath, the slightly weaker Bose QC35 reduced low frequency noise a bit better than the Sony WH-1000XM4 with the same earplugs. (Comparing the headphones without earplugs, the Sony are somewhat more effective than the Bose.)
Against mid- and high-frequency noise both headphones performed equally well.
- It appears that with respect to low frequency noise, foam earplugs are completely synergistic with the noise cancellation of some headphones while somewhat negatively affecting the ANC of others.
- There was a dip between 1250 and 2000 Hz (see graphs below), where the noise reduction maxed out at between 35 and 40 decibels. In particular for 2000 Hz, this concurs with studies looking at wearing earmuffs over earplugs. Current understanding is that bone conducted sound is largely responsible for the dip at 2000 Hz.
Noise reduction summary table (arithmetic averages, author’s ears)
Noise reduction details ANC headphones over foam earplugs (deep insertion)
The overall noise reduction obtained by wearing either the Bose (red line, graph below) or Sony (blue line) noise cancelling headphones on top of deeply inserted foam earplugs (Pretty in Pink, NRR 32) is excellent.
It by far exceeds anything achievable (at least for me) with current headphones or earplugs alone.
Moreover, for frequencies >200 Hz, the noise reduction achieved with both headphone models is virtually the same.
Now let’s take a closer look at the higher low and lower mid frequency range (125 to 1000 Hz) in which a lot of disturbing everyday noises fall:
With the Bose, I am achieving in excess of 50 decibels from 125 Hz. And the Sony follow suit from 200 Hz.
Why is this important? You are getting a huge boost in noise reduction against the barks of most mid- and large size dogs, snoring noise, traffic noise, honking, chatter, etc.
What is also surprising is that in combination with deeply inserted foam earplugs (Hearos Pretty in Pink), the Bose QC35 performed somewhat better than the Sony WH-1000XM4 for low frequency noise <200 Hz.
Worn without earplugs, the Bose headphones (orange line) cancel less low frequency noise than the Sony (green line), but Bose’s ANC appears to work better together with earplugs.
With the Sony, from 40 to 60 Hz (e.g. trucks, stomping), adding the earplugs only provides a very modest benefit over the excellent reduction achieved with the headphones alone.
Nevertheless, taking the entire tested low frequency noise range (<=250 Hz) into account the Sony headphones also benefit from adding earplugs: just take a look at the huge gap between the blue and green lines from 100 Hz on.
In a word, wearing foam earplugs underneath your noise cancelling headphones is a big win if you want to shut out the world around you.
How about listening to music or white noise with earplugs underneath?
Sound quality suffers, so I don’t usually do that.
Besides, music by itself helps to mask environmental noise, so I generally don’t have the need for earplugs while listening to music or watching a movie.
Depending on the situation, I do, however, play white noise or waterfall or rain sounds to mask noise intruders that make it through both the headphones and the earplugs.
This is very helpful to mask loud crying (e.g., on a plane), loud snoring, or chatter in a very loud chatter in café or office.
How to deal with the noise reduction dip at around 2000 Hz
Take a look at the graph again. There is a notch from about 1250 to 2000 Hz where the obtained noise reduction hovers between 35 and 40 decibels.
This is still a very good amount of noise reduction (just compare to the headphones alone) but babies are louder than that.
Unfortunately, some (not all) babies happen to cry loudest in that frequency range and moreover part of human speech also falls in this range.
What to do? In my experience, the best way to deal with this “weakness” is to play white noise that emphasizes this range.
For more information on how to mask speech with white noise (inc. apps and settings), take a look at the post How to Block Out People’s Voices.
If you are looking to use noise cancelling headphones together with earplugs against loud snoring, check the post Do Noise Cancelling Headphones Work for Snoring for details on how to set everything up.
Why is the dip there? Why aren’t we getting fifty decibels noise reduction in the range from 1250 to 2000 Hz?
The answer is likely that in that range the limits imposed by bone conducted sound are lower.
Provided noise is loud enough, it can bypass your plugged outer ear by vibrating the skull enough to excite the ossicles (the little bones that connect the eardrum to the inner ear).
Moreover, bone conducted sound can also directly reach your inner ear, even when you have completely plugged your ears (or a missing the ossicles).
The limit varies across the range of human hearing:
For example, for a honking sound at 500 Hz, you need a sound level of in excess of 50 decibels for it to become noticeable (with completely blocked ears) while at around 2000 Hz, the limit appears to be closer to 40 decibels.
For 2000 Hz, this 40 decibel limit has been observed in multiple studies that had subjects wear earmuffs over earplugs.
The dip in my test appears to include the center frequencies 1250, 1600, and 2000 Hz.
However, studies looking at ear defenders typically only test the frequency bands centered at 1000 and 2000 Hz, so you wouldn’t get values for 1250 and 1600 Hz.
If you want to learn more about the limits to noise reduction take a look at the post Are There Any Earplugs or Earmuffs That Block All Sound.
As in previous tests, I again used pulsed noises at increasing center frequencies (1/3rd octave steps) from 40 to 8000 Hz to compare my hearing thresholds with headphones/earplugs in place and with open ears. (Your mileage may vary!)
For deep earplug insertion, I did the test twice (on two consecutive days) in a cross-over design to reduce the risk that putting on one pair of headphones changes the seal of the earplugs (for better or for worse), affecting the result for the second pair.
The graph above plots the resulting averages. However the results for both days were quite similar.
For the normal insertion (next section), I conducted the test one time, using one insertion of the Pretty in Pink earplugs. I also did an additional test with a different pair of earplugs (Moldex PuraFit).
Noise reduction details ANC headphones over foam earplugs (normal insertion)
What happens if we don’t get the best possible earplug insertion?
How much noise reduction did I achieve by wearing ANC headphones over earplugs that were inserted shallower?
I call this normal insertion.
Difference in noise reduction for the foam earplugs worn without headphones
Let’s first look at the earplugs alone.
We know that the earplug insertion depth influences their noise reduction effectiveness against low- and mid- frequency noise.
The following graph shows my result for the Hearos Pretty in Pink earplugs at two different insertion depths (deep and normal).
For the deep insertion I did my best to get them inserted as deep as possible while still remaining reasonably comfortable. In addition, I used an earplug lubricant to make the insertion as smooth as possible.
For the “normal” insertion, I inserted the earplugs so that their end appeared to be about flush with the canal entrance.
The post How to Make Your Earplugs Block More Low Frequency Noise contains images and more details for deep and normal earplug insertion.
With deep insertion, I obtained an extra 10+, 8, and 4 decibels noise reduction for low-, mid- and high frequency noise respectively.
Now let’s wear the ANC headphones on top of the earplugs at normal insertion depth
This graph shows how much noise reduction, I obtained:
Again, the combination of ANC headphones and earplugs (blue and red lines) still significantly outperforms both headphones and earplugs worn alone.
In particular from 200 to 1000 Hz (higher low and lower mid frequency noise) the difference is large.
So if you want relief from honking, barking, or chatter, wearing earplugs underneath the headphones can make a big difference, even at an average insertion depth.
Note: I also conducted the same test with the Moldex PuraFit at a normal insertion depth. The results were very similar. In fact, they were even slightly better, but I can’t make sure I was getting exactly the same insertion depth.
Against low frequency noise from 40 to 125 Hz (e.g., truck rumble) I got mixed results with a shallower insertion:
- The combination of Sony WH-1000XM4 headphones and Hearos earplugs performed slightly worse than the Sony headphones alone, although I doubt I would notice the difference in daily life. Moreover, the noise reduction in this range was still very good.
- The Bose QC35 still benefited from adding the earplugs but now the performance from 40 to 125 Hz was very similar to that of the Sony headphones worn alone.
Wearing foam earplugs underneath ANC headphones can greatly boost overall noise reduction effectiveness when compared to either headphones or earplugs worn alone.
In addition, I find this combination more comfy than wearing earmuffs over earplugs.
In this post, we looked at the Sony WH-1000XM4 and Bose QC35 ANC headphones in combination with the Hearos Pretty in Pink foam earplugs (NRR 32).
This is primarily a solution if you feel disturbed by noise (e.g., snoring, barking, honking, chatter) and want to reduce it further without listening to music.
Music played through the headphones doesn’t sound very good when you are wearing earplugs.
However, playing a masking sound like white noise or waterfall sounds can help to further isolate yourself from noise in your environment (e.g., when sleeping on an airplane, getting rid of snoring noise, or trying to focus in a loud office).
Please note that these consumer ANC headphones have no noise reduction rating!
They are not recommended if you are looking to increase the effectiveness of your earplugs as a hearing protector.
If you need to double up for hearing protection, consider wearing ear defenders with a noise reduction rating on top of your earplugs.