Overpowering Speakers

I don't know that I completely understand your question.
If you like to play your tunes very loud, it is possible to blow them up with any amount of power. You are more likely to blow up speakers with a 20 watt receiver than a 300 watt amp.
When you turn the volume up, your amplifier ask for more electricity to produce the current or volume to get louder. When you keep turning it up, there comes a time when your outputs are giving you all the volume that it can produce. When you turn it up past that point, your amplifier doesn't know what to do with the extra electricity that it has drawn to get louder, so it passes the raw electricity on to your speakers, this is what we call clipping. Clipping distortion is the number one cause in fried voicecoils on speakers. Adding bass draws much more current than just volume alone, often, you can just turn down the bass to maintain a safe volume level. If the volume of your music is not loud enough, you are typically much better off getting more power, than replacing your speakers. Raw electricity can burn any speaker, even those rated for very high power handling. If you like the sound of your speakers, you are typically better off getting more power to play louder. This is a guideline, not a fact. There are other things that come into play... Excursion limits of drivers, voice coil size, crossover points & slopes etc. I hope this answers your question, Tim

Tim - Not sure I've ever heard things explained quite like you did there, but if it makes sense to you and Audio381 I guess that'll work.

Audio8381 - If you have a 300w amp, you're not sending 300 watts to the speakers unless you turn the volume up to max (and even then, not really). As long as you don't play too loud you'll be fine. The speakers will tell you - When they start to sound like crap, it's too loud.

The best explaination that I've heard is that the speaker pulls power rather than the amplifier pushing power. When you turn up the volume the speaker pulls the required power from the amplifier and if you turn the volume past the physical limits of the speaker it can cause problems. Speaker, like people, are not smart enough to know their limits.

I've heard the Focal 706v speaker rated for 25-125 watts hooked to Krell amps rated for either 300 or 400 wpc and the volume was very loud. The salesman turned them up to see how well they sounded at high volume. There is no need to ever play music that loud and they handled it without any issues.

Bottom line, don't get stupid with the volume and I wouldn't expect any issues.

Sebrof is also correct that you're very rarely sending the full rated power of your amplifier to the speakers. An EE buddy of mine told me that a rule of thumb on a reciever that shows volume in -dB is that full power is at 0dB and, I believe, half power was something like -10dB. Someone can confirm my memory, but I believe it takes twice the power to get twice the volume and double the volume is 10dB. I have CDs that I can listen to at 0dB, but very few. The majority of them I listed to below -10dB.