Welcome to Further Details, a series dedicated to ubiquitous but overlooked elements hidden on your favorite products. This week: the strips on your headphone jack.
The advent of wireless headphones is slowly laying the headphone jack to rest, but it’s not going out without a fight. The design, which traces its roots back to the late 1800s is sure to find a home on wired headphones, laptops, and various bits of audio equipment for years to come.
If you’ve ever contemplated the plug on your old set of wired EarPods or other headphones for even a second as you go to pop it into a jack, you’ve surely noticed the series of small, colored, plastic rings it has in varying numbers from plug to plug. What are those for?
The job of a headphone plug and jack actually is very simple: to communicate audio signals from the source and transmit them to your headphone’s where they’re played as audio. These rings play a crucial role, not because of what they do, but because of what they don’t.
Made of a non-conductive material (typically plastic) these rings serve to divide the plug into the various different conductive sections, known as pins, that actually do the work. Each plug has to have at least two pins (and therefore, at least one ring to separate them): one section to carry the signal, while the other to serve as a return path and ground, which helps to cancel out any distortion or interference the audio signal picks up along the way.
As a result, you can tell a lot about headphones by looking at their plug. One ring means mono playback. This basic plug only delivers one channel of sound to both the left and right earbud. Two rings mean stereo. These plugs have three pins, one for the left channel, one for the right, and one for ground. Three separating rings means you’ve got two stereo pins, and a microphone pin as well, and is the one you’re most likely to run into when you’re looking at smartphone earbuds.