Speaker
Power handling
Amp power vs speaker rating — and why a small amp is the real danger.
Simple
Compares how much clean power the amp makes to how much the speaker can take. Counterintuitively, the bigger danger is usually an amp that's too small, not too big — a small amp pushed into distortion is what actually fries speakers.
The theory
The engine compares the amp's power into the speaker's impedance against the speaker's continuous (RMS) power rating. A well-matched pair sits in a comfortable band. If the amp makes less than ~25% of the speaker's rating, the warning isn't "too quiet" — it's that you'll be tempted to crank a small amp into clipping. If the amp greatly exceeds the rating, it's flagged as fine with discipline: clean power is safer than dirty power.
For experts
The mechanism behind "small amps kill speakers" is spectral. A sine wave clipped into a square wave roughly doubles its RMS power and shifts a big chunk of that energy into high-order harmonics — energy that lands in the tweeter, which is typically rated for only a small fraction of the system's total power handling. So an underpowered amp driven to clipping can deliver more destructive energy to a tweeter than a much larger amp playing cleanly. The rule of thumb among installers — pick an amp rated up to ~2× the speaker's continuous handling — exists precisely so you never need to clip it. The engine encodes this inverted intuition: it warns harder about the small amp than the big one, because the failure physics, not the wattage arithmetic, is what destroys drivers.
Hard clipping approaches a square wave: RMS power roughly doubles and the odd harmonics carry the excess into the tweeter's band.