sub woofer efficiency

these 2 efficiency ratings have nothing to do with each other. audiokinesis is correct unless you buy a sub without an amp, which is not easy in todays market. any sub with enuf guts will work, finding a 'musical' sub is just jargon for finding one that is well designed and offers flat response and low distortion levels. most actual deep bass notes occur in the 30-40 hz region anyway so more distortion below this is not gonna be disastrous at most loudness levels anyway. lots of nitpicking with subs but well made subs between 500 to 1000$ will generally work fine if you take the time to place them in sweet spot and set controls right. acoustic room treatment becomes very important tho when you start pumping in really low sound waves....