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How Mufflers Work

By: Karim Nice  |  Updated: Feb 9, 2021

Active Noise-Canceling Mufflers

There have been a few experiments with active noise-canceling mufflers, especially on industrial generators. These systems incorporate a set of microphones and a speaker.

The speaker is positioned in a pipe, which wraps around the exhaust pipe so that the sound from the exhaust comes out in the same direction as the sound from the speaker. A computer monitors a microphone positioned before the speaker and one positioned after the speaker. By knowing some things about the length and shape of the pipes, the computer can generate a signal to drive the speaker. This can cancel out much of the sound coming from the generator. The downstream microphone lets the computer know how well it is doing so it can make adjustments if needed.

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For more information on mufflers, sound and related topics, check out the links below.

Muffler FAQ

Why does a car need a muffler?
A muffler reduces the amount of noise a car produces and controls the backpressure of the engine, which results in better performance and endurance. Over the lifespan of your vehicle, a muffler can prevent unnecessary stress and potential damage to the engine and exhaust system.
Do mufflers make your car louder?
No, mufflers are designed to "muffle" the noise your vehicle makes, quieting it down.
Can I drive without a muffler?
Some states require you to drive with a muffler. Additionally, some states make it illegal to remove a muffler if your vehicle originally came with a muffler.
How does a muffler affect performance?
Mufflers can have a positive impact on your car's performance. A quality muffler can increase power and performance, but to achieve this you'll want to look for a muffler that allows air to exit easily and quickly.

Originally Published: Feb 19, 2001

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