Ohms (Impedance) - The Weight of the Door

Technically, "Ohms" measure electrical resistance how hard the headphone fights back against the electricity trying to flow through it.

Think of the speaker inside a headphone as a physical door that needs to be pushed open and pulled closed thousands of times a second to create sound.
Low Ohms (e.g., 16 to 32 Ohms): This is a lightweight, hollow bedroom door. You can flick it open with one finger. Your smartphone has enough power to push it easily. Most consumer earbuds are low-ohm.
High Ohms (e.g., 80 to 300+ Ohms): This is a massive, solid-oak vault door.
If you try to push it with one finger, it barely moves. It sounds quiet, thin, and lifeless.
But if you put real muscle behind it, that massive door moves with incredible stability and control. The high resistance means the audio signal has to be much cleaner and stronger to push through, resulting in a terrifyingly precise sound if you have the right engine to drive it.