There are some methods if you have control of the amplitude and shape of the sound waves. One way to break a speaker is called "slamming" which is basically ma

There are some methods if you have control of the amplitude and shape of the sound waves. One way to break a speaker is called "slamming" which is basically making the edge of the speaker cone slam into the speaker box or grill. This is why higher quality speakers typically use foam on the outer edge instead of shaping the paper. If you've ever seen old car speakers that were worn and torn around the edge of the cone, that's almost always what happened to them. Banging is a similar method where the speaker gets over-extended in the negative direction so that parts of the cone continually impact the speaker cage or the coil itself. Cheap speakers are the higher risk, since even standard quality speakers tend to be purposely shaped to avoid this. I've abused a lot of speakers in my time (guitar player!) and I've never seen it happen. Both slamming and banging are problems caused by the audio wave's zero-crossing being too high or too low, but not actually at zero volts, where the speaker should be at rest. So the ambient sound from them don't have to sound "full blast" to cause the damage. The more obvious and easily accomplished method to ruin a speaker is to maximally extend both positively and negatively a rapid square wave. A treble speaker (tweeter) should be able to do this relatively safely, and it'll definitely break your ears before it breaks the speaker. But the larger the speaker is, the less likely it will be able handle the rapid strong voltage spikes. Sub-woofers aren't designed at all to handle it. As long as the frequency stays low enough, cheap (aka non-professional) crossover filters won't usually block them. You know when you are approaching the danger point when your sub-woofer makes an obvious clicking thud sound. Sometimes when that's happening accidentally, you'll hear harmonics so the low hum will sound like it is distorted and harmonized - kinda like the sound of a muscle car with two or more exhausts. 8-bit music gets its iconic sound because although the tones are initially coded as square waves, the rising and lowering of the voltage isn't fast enough to output true square waves to the speaker, and won't likely ruin them even at high volumes. That gives them that somewhat softened sound that is instantly recognizable as "chip tune", versus what would be more like the jarring X "WRONG!" tone you hear in some game shows, or a nasty alarm clock. Most soundcards won't allow it, but if you can push a positive-only or negative-only voltage, you will overheat the coil. It was certainly possible when PeeCees used to have a built-in buzzer before piezos were common (Piezos can be pulled apart without breaking anything, so they avoid a lot of these issues). But the sound card usually abstracts that away. An amplifier with a short circuit can easily do it, but the kernel isn't going to make that happen.