Originally Posted by Eyleron
Sorry about that, I've fixed it.
Aha! Thank you.
True. I think it's more like 6dB to 20-ishdB.
Depending on *what* we're listening to, it can be much lower. I've seen 20 dB stated as the guideline for Dolby/THX reference, but I've also seen music material with only a few dB. But I think this is relatively fair. 20 dB is not that insane though, that's not kW level unless you've got the most inefficient speakers known to man, or are out in a big field/stadium.
This is where I don't understand. I don't think gun barrels, car engines, or speakers are designed for maximum possible attainable stress, but in a continuous mode. The two are separate conditions. A speaker manufacturer tests and reports a speaker is 200 watts RMS and 800 watts peak (whether by destruction or distortion). Why are those two numbers separate? If it can do 800 watts for brief periods, why can't it for a longer period like 8 hours? Isn't it a thermal, heat dissipating issue, where the glues and voice coil will fail at high temperatures for too long? This makes sense to me. "I can lift X weight for one rep, but I sure can't hold it up forever."
Again, there is no RMS. There's just power. The continuous power handling rating on a speaker has to do with mechanical and/or thermal limits - the peak input is either a mechanical limit or a thermal limit (you can either put the driver into over-excursion which risks damage, or you can overheat the driver, which risks damage; depending on the design and the setup either is plausible).
It can't handle the higher output over a long period because you've exceeded the limit of the device. Those values are stamped on packaging just like "Dynamic Power" ratings on amplifiers - remember that 400W looks a lot nicer than 100W, and when you're competing with the 10,000W HTIB solutions you've gotta milk things a bit (remember that for the vast majority of customers, "watts" is the metric by which all quality and performance of any audio component is judged).
Burst/dynamic/momentary power is a worthless measure because it's so relative. It also isn't something you want to "plan in" - like I said earlier, if you want X you need something that can do X continuously. These "temporary" values are there to look nice on the box and assure the customer that the equipment has some tolerance before it fails. The same is true of anything else (you used cars and guns as examples, it applies there too) - you don't intentionally over-load an apparatus as part of your design.
The reason I feel this is important is that while one just says, "If it sounds bad, turn it down," but in reality, I think many enthusiasts are experiencing higher distortion and compression than they realize.
As long as you're not running whatever amplifier into clipping, the distortion it's producing is going to be very low relative to other problems (like the speakers, which produce substantially more distortion even when they're not being over-extended).
It's a very interesting topic, I will give you that. I'm just not convinced that it "matters" in the sense that not enough data is (or likely will ever be) available, and that even if data were available, it would go along the lines of "this is a hail-mary kind of scenario" in terms of output capabilities. Remember that you're asking about dynamic/peak power as a way to address transients in cinema or movies. What happens when there's lots of transients right after each other?* There's just too many variables to contend with, in order to want to consider this in planning out a system. It's easier to just assume that your peaks are your maximum continuous output, and be done with it.
* What I'm thinking of here would be higher tempo action movies, where you'll have a lot of "rapid-fire" peaks during some scenes. In some cases those peaks occur very quickly, one after another, and most meters won't even "fall" during the sequence (things like explosions or other bass-heavy effects). There's music that does the same thing. Is this still a situation for "dynamic power" to save the day? Perhaps I'm getting off-topic, I'm just seeing this as a "what about a situation where an amplifier that would normally be lighting the "clip" light up would have more power for a half second" and thinking "yeah but usually in those situations, the "clip" light will turn on and stay on until you (or the program material) bring the levels back down."