What adaptive ANC means and how much noise it cuts
How ANC works
Active noise-cancelling earbuds have microphones that listen to the noise around you and play an opposite sound that cancels it. It works best on steady, low noise: plane engines, train wheels, office air conditioning.
Hybrid ANC
Hybrid ANC uses microphones both outside and inside the bud, so it also catches the noise that has already reached the ear. The TESNA Pro2 have hybrid ANC up to 42 dB, the TESNA Free7 up to 38 dB.
Adaptive ANC
Adaptive means the cancelling adjusts itself. The TESNA Ultra measure how much noise reaches the ear and re-tune the cancelling as you move, up to 50 dB. The TESNA Pods Ultra over-ear headphones also have adaptive ANC, up to 45 dB.
What the decibels mean
The dB figure is how much the earbuds can reduce noise, in the maker’s conditions. Higher means more quiet. In practice, how well the bud fits matters just as much: a tip of the right size seals better.
Which noises it cuts well, and which it does not
Active noise cancelling works best on low, steady noise: the roar of aircraft engines, the rumble of trains and the metro, office ventilation, the hum of a fridge. The microphones catch these easily and the buds have time to make the opposite wave.
Sudden, high noises are another story: a slammed door, clinking glasses, voices around you, a crying child. ANC makes them quieter but does not erase them, because they change too fast. Here passive isolation does more: a tip that seals the ear canal well, or an over-ear cushion that covers the ear completely.
That is why the same decibel figure can sound different from one person to the next: what matters is how well the tip sits in your ear.
The TESNA figures side by side
In the TESNA range, ANC runs from 38 to 50 dB. The Ultra has adaptive ANC up to 50 dB and lasts 8 hours with ANC on, plus 32 with the case. The Pro2 has hybrid ANC up to 42 dB and 7 hours with ANC on, plus 28 with the case. The Free7, the smallest, has hybrid ANC up to 38 dB and 6 hours with ANC on, plus 24 with the case.
Among the over-ear headphones, the Pods Ultra have adaptive ANC up to 45 dB and 48 hours with ANC on, and the Pods M6 hybrid ANC up to 32 dB and 60 hours of battery.
The decibel figure is the maximum measured in the maker's conditions. What you feel depends on the noise, the fit and the mode you choose.
Transparency mode
The opposite of ANC is transparency mode: the microphones let the sounds around you into the buds, so you hear an announcement at the station, the cashier at the supermarket or a colleague without taking a bud out. It is useful on the street too, when you cross the road.
TESNA earbuds have no transparency mode: when you need to hear around you, take a bud out or switch ANC off. A good habit: ANC on the plane, the train and in the office; off, or one bud out, on the street and when you talk to someone.
How to pick the right tip
Without a tip that fits, even the best ANC loses a lot. Try every size in the box: the right tip holds firmly without pressing, and when you put it in, the noise around you drops noticeably even before you switch ANC on. If the bass is weak and you hear a lot of noise, the tip is too small; if it hurts after half an hour, it is too big.
Many people have ears of slightly different sizes, so you can use one size on the left and another on the right.
When to switch it off
On the street, switch ANC off or take a bud out so you hear traffic. Do the same to hear the announcement at the station or on the plane. With ANC off, the battery usually lasts longer.
Every model is in the shop, under noise cancelling earbuds and over-ear headphones.