A watt’s a watt, or is it? The technical definition of a watt is a unit of power, equivalent to one joule per second, corresponding to the power in an electric circuit in which the potential difference is one volt and the current one ampere.
To get a watt out of our amplifier we need voltage and current. Once we have that unit of power the magnetic motor system in the drivers converts that energy into movement that compresses the air and we hear sound. A watt is a watt, yet not all amplifiers at the same wattage sound the same. So what’s going on?
Amps with identical wattage ratings sound different because moving watts are different than steady-state watts.
If we were instead looking at wattage steadily powering a lightbulb we’d not really see any difference if that watt was produced by hydro or steam power. But in audio, we don’t listen to steady-state tones. Instead, we’re listening to rapidly moving air pressure. How that air moves defines what we hear.
Thus, we’d be more accurate to suggest that the motion of watts is what matters, not the watt itself.