Subwoofer: Watts or Brand Name?


I've read numerous forums and reviews looking for a musical (fast, accurate) subwoofer to pair with my Harbeth P3ESRs (no movie use planned). When comparing my Harbeths to previously owned bookshelfs ($400-500) they sound tighter and less sloppy. I'm looking for the same in a subwoofer. I've owned plenty of $200-$300 subs that are a let down. I currently own an Energy S10.3 (10", 200W RMS, ported) sub. It performs very well as an invisible fill, but I want to hear "detail" in the bass. I want to hear the shape of the bass guitar string, not just that a bass guitar string was plucked. I realize that a JL Audio E110 or Rythmik F12 would do this, but I can't go more than say $500 used. Am I dreaming? I have considered a REL T5 or T5i, but I have trouble believing that replacing my 10", 200W, ported sub with a 8", 125W, sealed sub would be an improvement. Compactness isn't important. In the end I wonder if watts are the determining factor. A 10" 200W sub from a high-end brand name (REL, Rythmik, Vandersteen) versus a 10" 500W sub from a mid-level brand name (Energy, SVS, HSU, Klipsch, etc)... which do you think would perform better? The main reason I ask is that in my $500-used price range I don't know if an entry level sub from a brand name would be better than a upper range sub from a mid-level brand. Or to make life simpler, do you have any recommendations for a $500 sub (used or new) that is tight, detailed, and accurate? Maybe an 8" would accomplish this more than a 10". 

I've read over and over again that subs are expensive because they need (1) high watts and (2) thick walls/bracing. I wonder if I focus on the heaviest, highest watt subwoofer I can find from a mid-level brand...maybe it will outperform an entry level sub like the Rel T5 based purely on physics.

robertjason1
Thanks everyone. I'm still not sure if the REL T5i or SVS SB-1000 will be an improvement over my Energy S10.3. I guess I could always trial the SVS and send if back if it's not noticeably better. I've heard people note that upgrading their subwoofer made a giant difference in overall sound... even with something as affordable as the SVS. Any more advice is greatly appreciated.
The REL is a lot easier to blend if you are running your mains full range. The SVS are a great choice if you are using some type of DSP or bass management, as they are tougher to blend. Those SVS sledge amps are very powerful, but that power must be carefully managed with music. 
REL pioneered the speaker level connection for better integration, but these days many other manufacturers have followed them.
From what I could find, the Energy S10.3 is not a particularly bad subwoofer at all. In my experience the sound quality of a subwoofer depends more on room integration than on the sub itself. I started with a very good sub (a B&W PV1d) and even that did not sound great until I added an Antimode 8033 for room equalization. The result was suddenly far tighter 'faster' and more 'tunefull' bass. My next upgrade will be a second PV1d to achieve smooth bass over a much wider listening area.. See here for multiple subs: http://www.acousticfrontiers.com/20101029using-multiple-subwoofers-to-improve-bass-the-welti-devanti...

robertjason

the REL is a very musical sub at any size. Even integrate into any existing system as well.

Happy Listening!