Many people feel that their earplugs don’t help against low frequency noise that is bothering them.
This could be traffic noise, hums from appliances and HVAC systems, stomping upstairs neighbors, and bass noise from music, to name a few.
I too used to believe that earplugs don’t do well against this type of noise.
However, experimenting with many different earplugs and ways of inserting them, over time, I have come to a different conclusion:
- Many earplugs (not all) effectively reduce low frequency noise if you can insert them very deep into your ear.
- Most people falsely assume they have inserted their earplugs well, when instead they have only filled half of their ear canal. As a result, they don’t get even close to the noise reduction potential of their earplugs.
While there is obviously a limit of what earplugs can do, you may be surprised how well they actually work.
In this post, we are looking at four things:
- Performance difference between normal and deep insertion for an earplug that works well against low frequency noise.
- How deep you need to insert earplugs for good performance.
- How you can test the effectiveness of your earplugs against low frequency noise.
Use this test to optimize the insertion your own earplugs.
- When you should change to different earplugs.
Earplugs’ low frequency noise isolation: normal vs deep insertion
I am reporting on my own results for the Flents Quiet Please for normal and deep insertion.
These cylindrical earplugs are relatively short (comparative earplug review for details), but have a normal diameter.
In my ears, they perform very well against low frequency noise (graph below).
Moreover, they are more forgiving than large tapered earplugs, i.e., they lose less of their effectiveness if I don’t get the insertion depth completely right.
Take a look at the following image to contrast normal insertion (to the left) and deep insertion (to the right):
Had I only shown you the left image, would you have thought that that is deep insertion?
Well, with the Quiet Please plugs that is normal insertion for my ears; deep insertion is shown in the right image.
Now, let’s look at how much of a difference deep insertion made in terms of low frequency noise reduction:
When inserting the Flents Quiet Please earplugs as deep as I can, I get on average 7 decibels more low frequency noise reduction (40 to 250 Hz) than when inserting them so that they appear to be flush with the ear canal entrance.
Practically speaking, -7 decibels are perceived as a 40% reduction in loudness (approximately).
(-10 decibels means halving the volume.)
Moreover, deeply inserted, the earplugs also perform better against mid frequency noise (>250 to 2000 Hz).
Please note that even at normal insertion, the Quiet Please perform quite well for me against low frequency noise.
We are talking about an additional 40% loudness reduction from an already good baseline.
Best of all, with these earplugs, I find deep insertion comfortable. I have no problems sleeping with them in my ears.
How deep should you insert your earplugs
For best low frequency noise reduction, insert your earplugs as deep as you can while still remaining comfortable. In general, they should be completely (or almost completely) contained in your ear canal.
In the next section, I have prepared low-frequency-test-noises to allow you to check how well your earplugs do. Once your earplugs work well enough, you’re good to go.
Now, I don’t know how long your ear canal is and which earplugs you are using, so I can’t tell you exactly what the maximum insertion depth looks like for you.
Your plugs don’t have to be in as deep as what you have seen in my ear above (don’t just ram them in).
I recommend you try to achieve something that looks at least like normal insertion shown in the next picture (but don’t force it):
Then do the test below to see how you are doing.
If you find the low frequency noise reduction to be insufficient, try to put them in deeper.
It may take a bit of trial and error to optimize the performance of your earplugs, but IMO it’s worth it.
If you are unsure how to insert your earplugs, start with my post How to Put in Foam Earplugs.
Then come back to this post and check the low frequency performance using the test noises provided below.
- If you have rolled up your earplugs well, but they fail to slide in easily, experiment with the insertion direction. For me, I have to insert them in a slightly upward direction, so they don’t hit the canal wall.
- If you ear canal is dry, dip your pinky in a bit of water and moisturize it.
Alternatively, you can also try an earplug lubricant (review post).
If you cannot insert your earplugs even after practicing, chances are they are too long or too large in diameter.
Test to improve your earplugs’ low frequency noise reduction
I have prepared noise files (repeating stomping noises) at increasing sound levels to help you test how much low frequency noise reduction you are getting.
You can use this test to improve the fit of your earplugs.
The stomping noises cover a good bass frequency range with a peak at around 58 Hz.
My suggestion is to aim for at least 20 decibels noise reduction. If you are not getting that, I recommend trying different earplugs.
Note: The following test is to designed to help you with low frequency noise annoyance reduction, not to assess the suitability of your earplugs as a hearing protector!
Conduct this test using a home stereo system with large speakers or a sub-woofer.
Choose a quiet room and time.
(Your phone speaker and smaller Bluetooth speakers won’t allow you to reproduce the lower stomping noise frequencies with sufficient intensity to conduct this test.)
You will need to connect your computer or your phone to your audio system.
Sit on a chair, at a distance of 6 feet (2 m) or more from your speakers.
1. First, determine your hearing threshold without earplugs
- The first test noise is recorded at a low sound level, so you may have to increase the volume quite a bit to hear it.
- Once started, the sound loops to give you enough time to find your hearing threshold. Press pause after you are done.
Play the following sound and adjust the volume down until you can just hear the test noise:
(The next volume down step should make the noise inaudible.)
For the following steps, do not adjust the volume any further!
2. Put in your earplugs
3. Play the following test noise (the same stomping noises at a 15 dB higher sound level)
If you don’t hear this test sound, great. Proceed to the next step.
If you do hear it, you are getting insufficient low frequency noise reduction and need to reinsert your earplugs:
Find out whether one or both plugs need refitting by pressing on either earplug with your thumb.
If the test noise goes away while pressing on a particular earplug, reinsert that plug.
If it doesn’t, you need to reinsert both earplugs.
If you are unable to make the test noise go away, try different earplugs (see next section for some ideas).
4. Play the next stomping noise (recorded at 20 dB higher sound level)
If you can’t hear this sound, you are getting a very respectable low frequency noise reduction from your earplugs. Congratulations!
Proceed to the next step to see how high you can go.
If you hear it, follow the instructions under step 3 to refit your earplugs and try again.
If you can’t make the noise go away after optimizing your earplug fit, I recommend trying a different earplug. See the next section for some suggestions.
5. Play the next stomping noise (25 dB higher sound level)
If you can’t hear it you are getting 25 or more decibels of noise reduction against this type of noise, which is very good.
Proceed to the next step to find out if you are getting 30 dB.
If you hear it, but couldn’t hear the previous test noise, you are getting at least 20 decibels reduction, which is good.
If you want more, follow the guidelines under step 3 and try again.
6. Play the next stomping noise (30 dB higher sound level)
If you can’t hear it, you are getting excellent noise reduction from your earplugs.
Proceed to the final step.
7. Play the final stomping noise (35 dB higher sound level)
If you can’t hear it, way to go!
When to try different earplugs
Often, tapered earplugs with the highest noise reduction rating (i.e., NRR 33) are quite large. They have to be very effective from 125 to 8000 Hz for a large number of people, with an expert inserting the earplugs.
On average, many large earplugs provide very good overall noise reduction, but that doesn’t mean they reduce low frequency noise (20 to 250 Hz) best for you.
In fact, for calculating the U.S. NRR, earplugs only have to be tested down to the 125-Hz-band.
Note: The NRR is designed to offer guidance regarding the suitability of a hearing protector for a certain noise level. In this post, we are concerned with low frequency noise annoyance reduction.
Trucks, generators, bass-heavy music, and stomping neighbors all emit sound waves way below 125 Hz.
In my experience, some smaller earplugs (that don’t have the highest noise reduction rating) can work very well against low frequency noise.
Two foam earplugs I have found to work well for me are Flents Quiet Please (white) and Mack’s SlimFit (purple).
- I prefer the Quiet Please. They perform somewhat better, and I find them a bit more comfy. They don’t last as long though.
- The Quiet Please are short but have a normal diameter while the SlimFit are short and—slim.
For more on how the Quiet Please and SlimFit compare, read my post Best Earplugs for Small Ears.
Both of them are bit small for me and completely disappear in my ear, but nevertheless, in particular against low frequency noise they do well.
This isn’t to say that large earplugs won’t work, but if your large ones don’t appear to be blocking enough noise, try down-sizing.
Update: In the meantime, I have also published the post Best Earplugs for Low Frequency Noise. It contains a detailed review, test, and shortlist of my favorite roll-down foam and reusable earplugs for low frequency noise reduction.
Let me know in the comments how you are doing.
Have a great day!
 In Calibrating the Insertion Depth, E. H. Berger compared a larger tapered earplug and a shorter cylindrical earplug down to 125 Hz. At maximum insertion depth, the tapered earplug slightly outperformed the cylindrical plug.
But, at a shallower insertion depth, the tapered earplug lost all of its advantage and, in fact, performed a lot worse than the cylindrical one.
In my own experience, this becomes even more pronounced at frequencies<125 Hz: some earplugs only work well at maximum insertion depth, which many of us can’t achieve, or at least can’t achieve and stay comfortable throughout the night. Others (like the Quiet Please) are more forgiving.