How Transparency Feature On ACN TWS Works?

ANC and transparency features in TWS often come in tandem, technically they rely on each other.

While ANC performance is varied from one to another, it’s hard to rate which one is the best – because fit and other related factors substantially decide the ANC performance. However, the AirPods and AirPods Pro’s transparency easily claims to be the best leaving behind Jabra Elite 85t, AKG N400 and Sony WF-1000XM3.

Transparency mode allows users to hear the ambient sound once it’s activated, but should it be as natural as we hear the sound without earbuds or be better?

The later means they can filter out the sound and enhance the voice we want to hear. Some newer earbuds even implement the different use cases (different modes) and users can switch back and forth manually or the earbuds will automatically adjust to suitable mode when they detect the environment noises.

For years I have quite good knowledge about the ANC feature – how they work and which one is better than other. But the transparency mode technically I don’t have that perspective that they may have potentially extend feature – hearing aid. But eventually I got it, Samsung recently published a report revealing that Samsung Galaxy Buds Pro can amplify the sound in ambient sound mode up to 20 dB. So people with mild, moderate hearing impair would benefit when using Galaxy Buds Pro, though Buds Pro aren’t FDA-approved (Food and Drug Administration) for use as hearing aids and I haven’t found any information that Samsung applied for it. So Buds Pro together with AirPods Pro are just sound amplifiers, not medical devices.

Transparency, hear-through or transparent mode are just the same, earbud makers just call it different names. It’s convenient when you want to talk/chat with your friend without taking off the earbuds and you are aware of what’s happening around like traffic warning or notification.

AirPods Pro are great at transparency mode I have to admit, they top the competition, listening to the ambient sound from AirPods Pro is more real and natural than others. So while ANC development is almost perfect, ambient sound transmission still have a room for development for other manufacturers.

How ambient sound is captured and delivered to your ears

Working principle: the sound is captured by a number of mics, these mics are also used as feedfoward noise in ANC function. They are located outside earbud’s housing, the sound turns to electronic signals (probably they go through refining process or filtering) and reproduced by the earbuds’ drivers. The sound clearly is not the sound passing through earbuds after passively reduction by earbuds sealed in the ear. So what we hear can be a mix of the sound that is not canceled out by ANC or passive noise isolation and “superimposed sound” from transparency mode.

But there is a delay because going through transparency mode takes time and the delay should be minimized.

Transparency mode comparison

Pink noise sources are selected for the comparison between Apple’s AirPods Pro, AirPods Max and Sony’s WH1000XM3 and 1 meter away from the dummy head. The test is conducted in the ordinary room. They work really good for frequencies from 20 to 2000 (the solid line close matched to dashed line) whereas, higher frequencies lead reduced noise level.

Analyze the principle of transparent mode in detail, and take you to a better understanding of ANC active noise-cancelling headphones-I love audio network
Credit: 52Audio

Double Transparency Modes

What happens when you wear AirPods Pro and over headphones AirPods Max (or Sony WH1000 XM3) with transparency feature switched on at the same time. You get double transparency mode from these two kinds of headphones. It will be very interesting, 52Audio conducted the test and below are what they obtained.

Analyze the principle of transparent mode in detail, and take you to a better understanding of ANC active noise-cancelling headphones-I love audio network
Credit: 52Audio –

On top of the figure, the solid black line represents the sound signal in dB over the range of frequency (20 Hz – 20,000 Hz) picked up by the microphone placed at the dummy head’s eardrum. The black dashed line represents the sound signal reproduced by AirPods Max and AirPods Pro on the left, and Sony WH1000XM3 and AirPods Pro on the right. The sound source to create noise originated from pink noise and headphones’ transparency mode is switched on.

On the bottom: the red line represent the Apple AirPods Pro transparent mode; the blue line Apple AirPods Max on the left and Sony WH1000XM3 on the right; the solid green represent sum of sound signal of red and blue. While the green dotted line represent the real measurement when wearing both Airpods Pro and AirPods Max (or AirPods Pro and Sony WH1000XM3)

Under 3000 Hz the green dashed line is quite matched with solid green, but higher than this point we see a significant difference. This can be explained by the fact that higher frequency sound is processed with major change in logarithm.

More built-in mic better transparency performance

Not quite, mic position also largely play a role for transparency. Even with the same mic, and logarithm transparency mode performance will vary if mics are placed at different directions to capture noises.

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