Why Do Headphone Jacks Have Multiple Black Rings, And What Do They Mean?

Apple's decision to remove the headphone jack from the iPhone 7 brought a sudden and jarring end to this ubiquitous audio connector (though you can still buy some smartphones with a headphone jack). You could either carry a bulky USB-to-3.5mm adapter or ditch the wires for wireless AirPods. While the AirPods' extensive feature set makes them a great upgrade, Apple's decision triggered a paradigm shift in consumer audio equipment, accelerating the transition to wireless devices and gradually bringing to an end the headphone jack's century-old legacy. Different versions of headphone jacks have been around since the 1880s, long before the iPhone was even envisioned. Back then, the longer version of the 3.5 mm audio jack, the 6.35 mm jack, was used by telephone operators to transfer calls.

The 6.35 mm audio jack used to have a single ring and an insulator near the tip, giving it the name TRS (tip, ring, sleeve) connectors. Most modern 3.5 mm audio jacks supporting microphones have two rings and an insulator, also known as a TRRS (tip, ring, ring, sleeve) connector. Apart from these two, there are TS (tip and sleeve) audio jacks with no rings and just the insulator. The headphone jack's configuration plays a crucial role in determining the cable's audio delivery.

The rings on a headphone jack separate the metal connector into different sections. Because of this, the rings are built with non-conductive materials such as plastic. As a general rule of thumb, more separators add more features to the connector. That said, TS or TRS headphone jacks are still used in specific audio equipment.

The simplest of the lot is the TS audio jack, where the tip and sleeve are separated by a plastic insulation. These audio jacks can only transfer a mono audio signal and are typically used in equipment such as electric guitars.

The addition of a ring to a TRS connector divides it into three sections: the tip, the ring, and the sleeve. The extra section on the TRS audio jack allows for the transmission of a stereo audio signal. As a result, both the left and the right earphones can have separate signals, leading to a richer audio experience.

The third and most feature-rich category of the headphone jack is the TRRS connector, with a tip and two rings dividing the jack into four sections. Apart from delivering stereo audio signals, the fourth section can handle inputs from the microphone. TRRS connectors are commonly used in headsets with built-in microphones, while TRS connectors are typically used for wired headphones without microphones.

Keeping aside the pain of untangling wired headphones, they once outperformed early Bluetooth headphones on numerous fronts. Wired headphones offered a seamless plug-and-play experience, without any cumbersome pairing process. On the contrary, pairing initial Bluetooth headphones (running on early Bluetooth versions) used to be a pain. Wired headphones needed no charging, while Bluetooth headphones could run out of juice even after minimal usage and sometimes suffered from audio lag. However, the biggest letdown for audiophiles was the poor audio quality due to compression and signal interference. Honestly, some headphones may still have many of these problems, so watch out while buying your next Bluetooth headphones.

Modern headphones have improved significantly in all these areas, thanks to advancements in Bluetooth transfer speeds and connectivity. Additionally, technologies like LDAC have significantly improved the audio quality on wireless devices with more efficient compression. That said, true audiophiles still prefer the lossless and uncompressed audio experience on wired earphones. Also, professional audio gear like guitars and keyboards uses different types of audio jacks for connection rather than going wireless.