How to get rid of hum and eliminate other noises from your audio and video systems

electrical noise

Editor’s note, July 16, 2017: We updated this story with new illustrations and new tips and tricks throughout. So you just unboxed your new entertainment gear, hooked everything up, and you hear a buzz, whine, hiss, chatter, or any number of other annoying noises that have been known to plague audio equipment. You might even see some banding or waves on your TV. So you take it all back to the store, only to watch the salesperson plug it in and have everything work perfectly. What the…?

I’d love to tell you that you did nothing wrong, but you may have, at least inadvertently. Then again, it could be bad wiring, defective equipment, or just a noisy electronic environment. Whatever the type of noise you’re hearing—and whatever the cause—here’s how to get rid of it.

Note: Some noise is inherent, such as tape hiss, or hiss when you turn up the gain on an input. It’s part of the equipment, and the only cure is generally better equipment.

TABLE OF CONTENTS

  • Ground loops
  • AC line noise
  • Wires
  • RF interference
  • USB/HDMI cable noise
SHOW MORE 

Ground loops

The number-one cause of unusual audio noise and weird video is the ground loop, simply because it’s so darned easy to create. The most common manifestations are a loud buzz or hum coming through the speakers, or scrolling bands on a TV screen. It could also be a much quieter, yet equally annoying buzz or hum that you only hear when the room is otherwise quiet.

A ground loop in entertainment equipment typically occurs when one or more pieces of equipment are plugged into the AC (alternating current) at different locations, then connected together by electrical (versus optical) signal cables—RCA, HDMI, composite, component—whose shielding is connected to ground. In the simplest terms, this creates a single-loop antenna that just loves to suck in various types of noise via electromagnetic induction. You can see how a loop is created in the diagram below.

ground loop

[Source”indianexpress”]