The Active Noise Cancelling Solution
On the previous page, we discussed how Peter Walker had tested 5 units and could not get them to reduce the noise, despite intensive testing. On this page, we will discuss how Peter Walker got his earpads to work properly. First of all, Peter Walker has exchanged several emails with QuietOn while trying to resolve the lack of noise reduction from the automatic noise cancellation (ANC). Here is a summary of the advice they have given:
You can switch between the Hearing and Silent modes by pressing the small black button (it is between the two round golden things). The button may feel a little stiff because it is so small. The difference between modes should be clearly audible. Please make sure the foam expanded to create airtight contact. Because individual ear canal may be in varied shape, the product needs to be in place with the right angle to work effectively. It will be helpful you can test the mode with some background noise (e.g., washing machine) to recognize the mode switching or you can snap your fingers to differentiate the mode switching. You wouldn't hear the finger snap sound when it is silent mode.
How active noise cancelling works.
The noise goes through the passive earplug into the ear, which changes audio response, phase and amplitude. The earplugs have a microphone outside which hears the noise. ANC electronics transform the sound and generate phase shift, before the speaker inside the ear plays anti-noise to cancel the original noise.
If the passive earplug leaks too much or too little, the noise and this anti-noise do not match inside the ear. That’s why it is crucial that the earplug are airtightly in the ears to get the full ANC performance. To get airtightness there needs to be a correct size foam tip and the device needs to inserted properly.
If you want to test the difference between passive and active noise cancelling, the best way would be to switch off both of the devices in a noisy environment using magnets. And after a while remove both magnets simultaneously which switches noise cancelling back on. Using magnets is quite difficult because the location of the magnets needs to be precisely in the right place and in the correct polarity. In the photo below, a metal-colored cylinder magnet is attached on the earplug with a bit of Blu Tack to switch off the device.
A test where one plug is in active noise cancelling and another only in passive mode is not going to give good clear response because human brain quickly adapts the hearing of the ears. The real difference can be heard only when both earplugs are switched between modes. When the device is correctly in the ear, the passive noise reduction matches well with the audio phase shift and tuning, and active noise cancelling works well. In the measured graph below, the significant difference between active and passive noise cancelling is clearly visible at the frequencies where the product is designed for:
This is an actual measurement done today in Janne's ear. Red curve is passive noise reduction (magnet switching of the power). Green is active noise reduction (normal operation). All of our devices have gone through several automated audio tests and that's why we are sure that the audio performance is equally good in all of them. Typically people find this experience very well. In our customer surveys 85% are saying that the performance is good (actually 75% saying that it is great ?). Hopefully this helps you all to get the full performance.
These devices perform especially well with low frequency noise. We have tested using the background noise from a dish washer or the same noise (https://www.youtube.com/watch?v=QLvUVfBUQqE) and when the silence mode is activated, we can immediately feel the difference. Therefore, you need to follow the instructions for the earplugs. Please make sure you use the correct size of the eartips so that the earplug is airtight in your ears. To find the right angle of earplug inserted to the ears is also a key point for the device to function properly. Please check all these perspectives and the update we just published in Indiegogo concerning ANC technology. Hope you can find the reason or tip to make the device function in your ears.
All the best from Finland and have a great rest of the week,
QuietOn team
I had sent them a video on my testing of their units next to a running washing machine in the bathroom. That video will not be made public as later tests have changed the conclusions for the better. Here is the email from their engineer which contains important information:
Thank you for your thorough explanation on the video. So, the button and magnets are working.
As we mentioned in our last update: "If the passive earplug leaks too much or too little, the noise and this anti-noise do not match inside the ear. That’s why it is crucial that the earplug are airtightly in the ears to get the full ANC performance."
The matching of the noise and anti-noise is more critical on QuietOn Sleep than it is on the Original because Sleep uses feed-forward and Original uses feedback technology. It is quite dependent on the physical properties on the individual ear. The Sleep earplugs are simplified as far as possible in order to keep the size small. The anti-noise is generated from the signal of the microphone with a fixed set of filters which is tuned to match an average user's ear. The original noise gets into the ear passively attenuated partly through the foam of the eartip, partly through tissue, and partly between the skin and the foam if there is such a gap (caused by improper fit or too much hair on the skin etc.).
It turns out that it is rare to find a case of too tight fit and additional sound leak is more common. You tried to press the earplug firmly in the ear and heard a small improvement which suggests it might have been too poor passive attenuation to begin with and the active noise cancelling doesn't work properly with that.
- A small leak causes passive attenuation to become weak at low frequencies while higher frequencies are mostly OK. This makes the ANC noise reduction weak and low frequencies are affected the most. Or if it does work, it works only in a narrow frequency band.
- Insufficient insertion depth causes passive attenuation to weaken more uniformly across the frequency spectrum. This makes ANC weak in a wider range of frequencies.
- In the rare case of too good a seal, the noise level starts to increase again as you push the earplug deeper. You'd hear the anti-noise from the device alone mostly, as original noise is passively attenuated more. Even in this case the noise level doesn't exceed the typical level of passively attenuated noise.
As you have done a thorough testing, there are not many things left to try.
- Try to moisten the surface of the foam tip to improve seal. This is not practical in the long run but it could give more information if the issue. (Side note: the foam tip will expand if it gets very wet. It goes back to normal after a long dry.)
- I apologize if this gets too personal: try an ear trimmer if you have one.
- Try the large tip too if you haven't.
- It is entirely possible that the earplugs just don’t fit some ears. In this case, a refund could be agreed.
Best regards,
Matti Nisula
There was one thing in his email that stood out a mile to me - I hadn't tried the large foam tips.
The reason I had not tried the larger tips was because I found the medium sized ones to be uncomforatble and had tried the small tips and found them to be more comfortable. I had therefore discounted the large tips entirely - my mistake. I exchanged the tips so that I could try the large ones - I was open to trying anything to solve this issue. To my surprise, the extra width of foam did need a little longer to settle down in my ears, but when they did, they were more comfortable than the medium ones and gave a better seal from external noise. Armed with two magnets, I tested the earpads next to a noise source (an electric ventilator) and was surprised to find them working!!! I then tested them next to the washing maching where the noise cancelling had failed last time - this time they reduced the noise even more than my expensive Parrot Zik 2.0 headphones, that had reduced the noise by 30dB.
QuietOn had announced that you can test the ANC function with small magnets. By putting small magnets near the earbuds while wearing them, you can get the electronics to switch off in situ.
In quiet mode (default), this allows you to hear the difference between passive noise reduction (just the earpads without the electronics) and active noise reduction. The difference was not that massive, but is noticable. In hearing mode (after pressing the small button), the magnets have the opposite effect. Without the magnets nearby, you can hear your surroundings quiet well and when the units are switched off by the magnets, it gets quieter due to the passive noise reduction from the earpads.
So my suggestion to all those that find the noise cancellation not working, try the large tips and press the earpads in as far as you can.
They are not only MORE comfortable, they create a better seal which allows the ANC function in the earpads to operate.
If the noise reduction is still not working, try each tip size in turn and ensure there are no excessive hairs or wax in your ear channels.
You can leave comments below. Good luck.
Finally, in order to charge your QuietOn headsets (and your mobile phones, etc) more easily, it is highly recommended to order magnetic USB cables.
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