With a Lightning a USB-C headphone you plug the headphone directly into the Lightning port (on Apple devices) or USB-C port (on Android devices). A standard headphone plug is an analog connection while this creates a direct digital connection. The headphones are powered by your phone (they use only a little bit of battery power) and have an integrated DAC (digital-to-analog converter) that's usually superior to the DAC in your phone.
In early powered radios, the headphone was part of the vacuum tube's plate circuit and carried dangerous voltages. It was normally connected directly to the positive high voltage battery terminal, and the other battery terminal was securely grounded. The use of bare electrical connections meant that users could be shocked if they touched the bare headphone connections while adjusting an uncomfortable headset.
A. Near-field communication, better known as NFC, is a wireless connectivity protocol similar to Bluetooth. NFC uses less power than Bluetooth and is faster when pairing devices, but it only has a range of about four inches. Some headphones use NFC technology to drive the process of pairing headphones with smartphones, but because of the range, it’s not used to transmit sound. While both Android phones and iPhones include NFC chips, it’s not accessible in Apple devices, so if you want a pair of headphones with NFC, you’ll need to own an Android phone to take advantage of the faster pairing.
Despite big promises from Bluetooth’s only Hi-res codec, the standard doesn’t really deliver at best, and it falls far short with its basic 330kbps setting. Both the 660kbps and 990kbps connections offer decent quality, but the 330kbps setting has a lot of noise—and a comparatively poor frequency response with higher-def content. You probably won’t hear it, but it definitely falls short of the marketing.
Earbuds have small speakers that rest on the ear canal of the wearer. These are usually much less expensive than on-ear and over-ear headphones and reproduce the sound well. However, outside sounds, such as traffic or power tools, can get past the earbuds and interfere with your enjoyment. Earbuds also don't stay in place very well if the wearer is moving much, such as exercising. These also are lower fidelity than on-ear and over-ear headphones.