For instance. My speakers are 91db @1w @1 meter, fairly efficient. I sit 8-10' from my speakers in a relatively small room. to play at an average volume of 90db (quite loud, but not quite concert level) takes less than 10w of power. If I want lots of headroom for dynamic material like classical music (say +15db from average) I will need to have 50w total power for the highest peaks.
No, for a +15dB peak you would need
451W for a 105dB peak with 3dB headroom using those specs. That means you are
using 10W of the total power of your receiver or amp, but the amp needs to be capable of delivering 451 during that peak to avoid clipping.
That calculator does not factor in room gain or the room size either, so your actual power requirements could actually be slightly lower or higher.
The range means that feeding the speaker with less than the lowest amount of power listed could damage the drivers, and the max rating means that is the most it can handle PEAK before something fries; in both cases, damage to the speaker is likely. The fact is, if you have sufficient power to achieve the SPL you are looking for in your room
without clipping, it doesn't really matter what the ratings on the speaker are because most speakers will be OK with an unclipped signal. The amount of power actually used by the typical speaker during normal listening is likely very low, on the order of a few watts. When you clip the signal, the amount of power drawn goes up exponentially.