Narrowcasting is a term that describes delivering information or media to a specific or narrow group of people. This can now be done with sound, letting an individual get the specific message.

Meta-materials could help us silence buildings and cities through the use of these novel material applications.

As these conversational interfaces include, there may be further noise pollution inside, after the proliferation of these devices.

Self-driving cars and electric vehicles will make the city quieter. Potentially, it could even eliminate the need for sirens and horns. NASA hopes that by 2025, the most-advanced aircraft will be half as loud as they are now.

Further understanding of noise and its impact on humans will lead to a divide in those that have the benefit of quietness and those that don’t. Noise exposure has also been linked with cognitive impairment and behavioural issues in children, as well as the more obvious sleep disturbance and hearing damage. Currently, houses on busy roads are often cheaper than those on quiet roads.

New devices can combine wireless IoT networks and loudspeaker arrays with noise cancellation. A microphone is placed in the environment that senses sounds and sends them over wireless signals to an open earpiece (i.e. without the need to occlude the ear canal). Since wireless signals travel thousands times faster than an acoustic wave, the earphone can receive the sound information much faster than the actual sound, being able to effectively cancelling it. A similar approach could also be used for free-field noise control, using loudspeakers instead of wearable devices.

Current research on acoustic monitoring of ecosystems seems to suggest that a large number of information can be gathered from acoustic sensors, such as number and location of taxa, general healthiness of the flora and fauna, etc. A similar approach could be potentially applied for monitoring pollution or traffic within an urban environment, just by using a simple microphones array, which can be put on a light-pole, rather than having to install complex devices around the street.

As we now are aware of the protein that creates sound, we might be able to augment it, creating super hearing for those willing to augment their bodies.

As carmakers have included fake noise to their cars, perhaps cities might do the same thing as they go quiet.

These devices have the potential to maks sound completely for individuals.