Panasonic noise cancelling headphones, like all other headphones in its category, use the active noise control technology, which is the key component that blocks out unwelcome sound from the outside environment. Active noise control, or ANC technology, usually involves microphones placed inside both of the earpiece housing units, and a special circuitry that takes the microphone signals and converts them into an anti-noise signal. When the speaker drive of the Panasonic noise cancelling headphone emits this anti-noise signal, it produces a phenomenon called destructive interference which cancels out any ambient noise that filters into the hollow space of the headphone housing units.

This technology in the Panasonic noise cancelling headphones makes it possible for the user to quietly listen to music without setting the volume to very loud levels. There is no need to compensate for loud ambient noise with louder speaker music, because the unwanted noise is already cancelled out. When each of the headphone ear units covers your ear completely, the technology creates a sort of “dead space” within the hollow space of the headphone and allows you to play music at softer levels. The better the construction of the headphones, the better this quiet dead space will be, and the more tranquil the environment will become when you put this on.

However, headphones like the Panasonic noise cancelling headphones do not completely cancel out every ambient noise that filters through the headphones. The active noise control technology only cancels out lower frequency sounds, and noise that generates a continuous hum or buzz. It can’t completely block out human speech, sound signals that fluctuate, and other high frequency sounds. Blocking these sounds out requires much traditional means, such as sound insulating foam that is circumaural in design, meaning, the headphones completely cover the ears. This is a preferred technology because it is cheaper and feasible than directly moving the active noise control circuitry adjacent to the eardrums, which is of course technically impractical.