A Eulogy for the Headphone Jack
To any headphone jack, all audio is raw in the sense that it exists as a series of voltages that ultimately began as measurements by some tool, like a microphone or an electric guitar pickup or an EKG. There is no encryption or rights management, no special encoding or secret keys. It’s just data in the shape of the sound itself, as a record of voltages over time. When you play back a sound file, you feed that record of voltages to your headphone jack. It applies those voltages to, say, the coil in your speaker, which then pushes or pulls against a permanent magnet to move the air in the same way it originally moved the microphone whenever the sound was recorded.
Smartphone manufacturers are broadly eliminating headphone jacks going forward, replacing them with wireless headphones or BlueTooth. We’re going to all lose touch with something, and to me it feels like something important.
The series of voltages a headphone jack creates is immediately understandable and usable with the most basic tools. If you coil up some copper, and put a magnet in the middle, and then hook each side of the coil up to your phone’s headphone jack, it would make sounds. They would not be pleasant or loud, but they would be tangible and human-scale and understandable. It’s a part of your phone that can read and produce electrical vibrations.
via https://medium.com/@flimshaw/a-eulogy-for-the-headphone-jack-aabda6c66cd8