How do aux cords work?
In: Technology
The standard 3.5mm audio connector is one of the simplest standards out there.
The connector you’re familiar with has somewhere between two and five metal segments separated by small pieces of plastic. Each of these segments connects to a wire within the plug or socket. One of these connectors – usually the one at the base of the cable – will connect to the ground. The other connectors often carry some form of audio signal. One of the clever elements is that every element *except* the ground is a standard length – the ring at the top is a certain length, then each subsequent ring is the same, then the one at the very base is however long it needs to be to work. This means that inserting a cable with 4 connectors into one with 3 connectors just sends one of the connectors to ground, and nothing (usually) happens.
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To understand how the cord actually sends sound, we need to understand (briefly) sound. At the most basic level, sound is produced when air varies back and forth in pressure. If the sound varies between two levels slowly, it generates a low pitch. If it varies quickly, it generates a higher pitch. There’s more complexities at play, such as multiple different variations on top of each other, but *every* sound can be represented by tracking the pressure over time. The wires in your aux cord carry a voltage, which undergoes the exact same changes as the sound does. The device on the other end is designed to produce pressure in the air around it based on the voltage it receives – which we perceive as sound. The aux cord just carries a voltage from one point to another, and doesn’t do anything fancy. There’s no mechanism to make sure devices are compatible, or to carry digital signals – this is possible, but it requires work outside the cable rather than just being simple.
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