Okay i really need some help with this one. I'm going to be putting together a component system. I will have a sub box and a combination horn/tweeter box (all running through an external crossover, of course). I'm trying to decide what size speakers to use in the sub box. I was thinking about doubling up on 300w 18" speakers to get some serious bass, but then I feel like i'd need one hell of a mid/high box to compensate for the extreme amount of bass. So here are a couple questions I really need help with: 1)Do woofers lose full-range coverage as they get bigger? That is, will a 15" speaker sound better than an 18" speaker if i'm using it to cover full range and not just low frequencies (assuming i have plenty of power)? 2) If i have two 300w woofers, do I also need 600 watts of mid/high frequency output in the form of tweeters and horns? If not, what ratio should there be in a slightly bass-heavy system betweeen low and mid/high output. Thanks in advance for the help.