What is Impedance and sensitivity?
How hard the headphone is to drive.
Short answer
Anything over ~80 ohms should be paired with a DAC/amp, budget for it.
Impedance and sensitivity when buying a headphones & earbuds
How hard the headphone is to drive.
Why it matters: High-impedance wired headphones sound thin from a phone and need an amp.
Look for: Anything over ~80 ohms should be paired with a DAC/amp, budget for it.
Full Headphones & Earbuds buying guide