Active noise cancelling headphones對於哪種噪音效果最佳

Active noise cancelling (ANC) headphones are most effective against low-frequency noises that are consistent and predictable, such as the hum of an airplane engine, the rumble of a train, or the constant drone of office air conditioning. These headphones use microphones to pick up external noise, and then generate an inverse sound wave to cancel out the noise.

ANC is less effective against:

1. Sudden noises: Since active noise cancellation requires processing time to analyze and generate the inverse wave, it may not be able to block sudden, short noises like a door slamming or a loud conversation.

2. High-frequency noises: High-frequency sounds, such as the sound of a baby crying or the chatter of people, are more difficult for ANC technology to effectively cancel out.

3. Non-steady noises: Noises that are not consistent, such as the irregular sound of a keyboard or the changing pitch of a conversation, can be challenging for ANC to handle.

4. Ambient noises with varying frequencies: Complex, multi-frequency noises like those found in a busy city street or a construction site can be difficult for ANC to fully cancel out.

5. Intermittent noises: Noises that come and go, such as the sound of a car engine when you're stopped at a traffic light, can be harder to predict and counteract.

For these types of noises, passive noise isolation provided by the design of the headphones (e.g., the fit, the materials used, and the seal around the ear) becomes more important. Over-ear ANC headphones typically offer better passive noise isolation than in-ear models due to their larger size and ability to create a better seal around the ears.

It's also worth noting that some ANC headphones have an ambient sound mode or transparency mode, which allows environmental sounds to be heard. This can be useful in situations where you need to be aware of your surroundings, such as when walking on a busy street or when traveling.