The same headphone is often sold in two or three impedances — 32, 80, 250, 600Ω — and the forums will tell you the high-ohm one “needs a proper amp”. That is only half true, and the half that is missing is the important one.
Beyerdynamic quotes the same 96 dB sensitivity for every impedance version of the DT 880 and DT 990. Read that literally and it means all three versions need identical power to reach the same loudness. What changes is how that power is delivered: the 600Ω version needs a lot of volts and hardly any current, the 32Ω version needs the opposite.
So the question is never “can my source make enough power”. It is “can my source swing enough volts” for the high-impedance version, or “can it supply enough current” for the low-impedance one. A phone runs out of volts long before it runs out of anything else, which is exactly why 600Ω headphones have their reputation.
There is a second, quieter reason to prefer the higher-impedance version if your source can drive it: audible hiss scales with sensitivity in dB/V, and a 600Ω headphone has a much lower dB/V figure than the 32Ω one. Same headphone, far less noise from the same amplifier. The trade runs the other way too — low impedance is more vulnerable to source output impedance.
The stubborn myth this page exists to kill is “more ohms means harder to drive”. Ohms and difficulty are two different axes. A 600Ω DT 990 is easier to drive than a 60Ω HiFiMAN Susvara by a wide margin, and the comparison tool will show you that in one screen.