Most new wireless earbuds and headphones come with two listening modes that sound like opposites: active noise cancelling (ANC) and transparency (sometimes called ambient or hear-through) mode. Both rely on tiny microphones in the ear cups or buds, but they use that sound in very different ways. Knowing which to pick makes your commute, office day and evening walk noticeably better.
How active noise cancelling works
ANC listens to the sound around you and plays back an inverted copy of it. When the original wave and the inverted wave meet, they cancel each other out. This works best on steady, low-pitched sounds such as aircraft engines, rickshaw rumble, air-conditioner hum and generator drone. Sudden, high-pitched sounds like voices or a car horn are harder to cancel, so you will still hear them, just quieter.
"Hybrid" ANC, used in OHMZ Buds Pro and Wave ANC, combines microphones on the outside (feed-forward) with microphones inside, close to your ear (feedback). The inside microphones check what actually reaches your ear and correct the result, which gives a deeper, more even quiet.
How transparency mode works
Transparency mode does the reverse: the outside microphones pass ambient sound through to your ears, mixed with your music. A good seal from ear tips normally blocks a lot of outside sound, so this mode helps you hear announcements, traffic and conversations without taking your earbuds out.
When to use which
- ANC on: flights, long bus or train journeys, open-plan offices, studying, and any time you want to listen at a lower, safer volume.
- Transparency on: walking or cycling near traffic, waiting for your stop, quick chats at the counter, and when you need to hear your name called.
- Both off: quiet rooms at home, when you want maximum battery life.
Tips for the best results
Noise cancelling depends heavily on fit. If ANC sounds weak, try the next ear-tip size; a tip that is too small lets outside sound leak in and the cancelling cannot keep up. With headphones, make sure glasses arms or hair are not breaking the seal around the cushion.
Remember that ANC uses a little extra battery. On Buds Pro you get about 7 hours per charge with ANC off and around 5.5 hours with it on, and the case tops them up several times over. Finally, some people feel a slight "pressure" sensation with strong ANC at first. It usually fades after a few days; if it does not, a lighter ANC level or transparency mode is a comfortable alternative.
