Retail noise cancelling headphones like the ones from Panasonic use active noise control (ANC) to cancel the unwanted ambient sounds that have lower frequencies. ANC means using one or more microphones positioned near the user’s ears, along with electronic circuitry that makes use of the microphone signal to create an antinoise signal. When the headphones’ speaker driver generates produces this antinoise signal, the resulting destructive interference in the sound waves cancels ambient noise from being heard by the wearer of the headphones. The level of active noise reduction you can get with a pair of Panasonic noise cancelling headphones like the RP HC300 can be more than 18 dB at 300 mHz, and environmental noises from vehicles and machines like air conditioners are reduced by an eighth.

As for noises with higher frequencies, Panasonic noise cancelling headphones have soundproofing to reduce the extent that such noises reach the wearer’s ears. Soundproofing is preferable to the alternative, which would increase the demand for complicated electronic circuitry. Besides, ANC is less efficient at higher frequencies. If you were to insist on actually cancelling high-frequency sound waves coming to your ear from all directions, the sensor and the emitter for the antinoise waveform would need to be right beside your eardrums, and such a configuration of electronics can hardly be considered technically feasible, unless maybe you happen to be a cyborg.

To generate the necessary antinoise signals, Panasonic noise cancelling headphones may be powered by batteries. The high-performance RP HC300, for instance, comes with an R03/LR03 AAA battery. You can use rechargeable batteries with this headphone model. The battery also powers the operation indicator light. When the operation indicator fails to light or the battery has gone dead, you will not be able to hear sounds from the headphones.

Another thing that you should probably know about this consumer electronics gadget is that while they work well with ambient sounds that are continuous (e.g., the sound in an airplane cabin or the hum of a refrigerator or air conditioner), audio signals that can change rapidly (e.g., human voices, telephones, and car horns) can remain relatively intact when Panasonic noise cancelling headphones are in use.

Whether you want to read a book in peace while you are on a plane or just ride the train without having to hear the noise that the engines make, you can use Panasonic noise cancelling headphones. Your trip will go much better, and you can arrive at your destination in a good mood.