Generally speaking, it indicates the power that a headphone or speaker can withstand without being damaged.
It is given in milliwatts, where watt is the unit for power. By definition, one watt is the power that results when energy of one joule is converted within one second. The unit “watt” was named after the Scottish inventor James Watt (1736 – 1819). Often manufacturers mention this value together with a reference value of 1 kHz.
Maximum input power = short-time duty
The maximum input power describes a short-time power handling that headphones can tolerate without being damaged. So please be careful which headphone jacks you plug your headphones into. Some preamplifiers output so much power that the headphones can get damaged.
(Keyword “impedance”; see also “What does impedance mean for headphones?”).
Rated power = continuous load
Some headphone manufacturers also specify the nominal load capacity in their technical data. This reflects the value that can be endured permanently without damaging the speaker.
