Let's talk about the concept of noise cancelling.
Sound is conducted through the atmosphere as a wave. When the wave strikes your ear, the mechanism of the ear translates the vibrations into an electrical signal that is perceived in the brain as sound.
Now, the "noise cancelling" process proposes to create an identical wave of the opposite phase, so that what reaches the ear is no wave at all, which is processed as no sound.
Most noise cancelling headsets begin this process by sampling the sound waves at the mouthpiece, or microphone installed on the boom of the headset. As an average, this point is adequate, and will result in the production in both headsets of a "cancelling" sound wave that will approximate the identical but opposite sound wave to achieve something approximating no sound.
Unfortunately, sound in a cockpit is not uniform, and while the average is close, it's not as good as it could be. Usually, there will be more sound on one side of the head than the other, or different sounds on each side. Typically, the sounds to the outboard side will be louder than the sounds inboard.
What if, though, the sound could be sampled at each ear, and an individualized "identical but opposite" sound wave could be produced for each ear that would more perfectly match the sound that actually reaches that ear, which would in turn produce the appearance of no sound in the ear?
Well, that's exactly what Bose does. There's not one single cancelling wave produced based on what is perceived at the boom microphone. On the contrary, there is a microphone on the dome of each earpiece, and two separate cancelling waves are custom produced for each ear. The result: the very best noise cancelling that one can experience.
Other headsets may have better passive protection, others might hold up to more abuse due to a more rugged construction. Consequently, one might choose those others over Bose. However, none can beat Bose for Noise cancelling, and none can top their customer service.
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