I am often fascinated by discussions that refer to the 'amount of amplifier power needed' and how folks commonly determine what they feel is appropriate.
Unfortunately the manner in which MOST equate speaker power and amplifier power is utterly incorrect!
Too often it is akin to someone choosing a car based upon its top speed compared to the speed limits posted on the highway! And having dutifully chosen that car based upon misleading units, they then wonder why they can't pull a boat. And in our case, LFs and subwoofers are boats. Rather large boats. But its rather interesting that topics such as crest factors and duty cycle are never discussed - or even mentioned.
Instead the discussions remain in the arena similar to the discussion of light bulbs, where folks often use wattage ratings, indicative only of how much current is transformed into HEAT, when they are referring to light output - properly measured not in watts, but in candle power or lumens. Note also, that speakers, amps, light bulbs, and space heaters are also commonly rated in terms of watts, with more than a few thinking that this rating, at least in the case of speakers, amps and stereos, thinking that this has something to do with output loudness!:rofl:
And doesn't it? I can say with certainty that my 100 w bulb certainly sounds louder than that 40w bulb!
Well, not exactly. But those ratings are great if you want to compare the heat output of your toaster or space heater or light bulb with that of your speaker just before it enters a destructive mode of operation!:gulp:
Oh, but that is NOT what you were really interested in? Hmmm....
So, we could spend days parodying the commonly held, but utterly incorrect, beliefs about audio 'power' ratings.
And now more than a few should be wondering, "Then what exactly DO those ratings mean? And if they are not appropriate, what is?"
...And why can't my Yugo, rated with a top speed of just over 90 miles an hour, plenty fast to accommodate most highways in the country, tow my 26 foot long Boston Whaler through the Rockies?
Here are a couple of papers that attempt to explain some of this.