Car stereos are an integral part of many cars and a must-have for many car owners. It's common knowledge that these auto accessories provide music for millions of drivers every year, but it's less well known how they contribute to an overall quieter ride. Here is how car stereos complete another of their many tasks, active noise control.
A Computer Does Most Of The Work
Cars with active noise control, or ANC, work by receiving external sound through a microphone in the car continuously. This microphone converts the external audio signals into electronic ones to send to the car's computer. Every modern car has a computer for a variety of jobs beyond ANC, varying from managing airbags to cruise control and even car stereo systems with a digital display. This computer will interpret the soundwaves to determine what "anti-wave" to produce.
Your Stereo Does The Rest
The computer can't work alone. The car stereo itself will, at the instruction of the computer, produce sounds that are essentially the opposite of the externally received sound waves. It operates under the same principle that noise-canceling headphones use - two sound waves of equal magnitude (how tall it is) and opposite cycles (the visual pattern, over time) will cancel each other out and the human ear will interpret nothing or very little at all. This anti-wave work that your stereo does, combined with the insulation normally added to your car, creates a smooth, noiseless ride.
A Little Extra Noise
This noise cancellation is so effective that many car manufacturers are finding that they need to add noise artificially to otherwise silent cars. They don't do this by reversing the ANC or lessening it by programming the car stereo to emit anti-waves of a shorter magnitude than usual, but by programming the car to add noise under certain speeds. This is meant to keep those with vision problems safe when dealing with quiet electric cars while also allowing drivers to have a quiet ride other times.
Car stereos are a popular, if not automatic, addition to most cars across the country. These stereos provide entertainment for millions across the country but have hidden features that many are unaware of. Car stereos work in coordination with the computer system every contemporary car has to produce soundwaves that are the opposite of those being received from outside the car. These soundwaves, combined with the external ones, will cancel out, allowing for a ride so quiet some cars have to be fitted with artificial sound.
