Noise eliminator

Sometimes when you’re speaking at the phone you need to do it loudly because on the other side there’s too much noise or even because there’s too much noise where you are. This device would work as a barrier eliminating the noise around you on the one side and muffling your voice on the other, so that you can speak loudly without bothering everyone. This device would be like a helmet but would cover only the mouth and one ear. The shape can be described as two Ls, one horizontal covering the mouth and making the contour of the face and the other, a vertical one, covering the ear. They would join on a single piece so that a phone’s handset could be placed inside it.

Hypothesis 1: simple physical sound barrier – the device would cancel noise from and to the outside as result of the sound absorbing characteristics of its material.

Hypothesis 2: active sound nullifier (inverse sound wave) – I don’t know many details about these devices but they work by collecting the sound and returning the same sound wave but inversed, thus cancelling (or reducing the amplitude) of the original one.