I have a subwoofer right now. It is an Infinity TSS 450. It is a 100 watt, 8" woofer. My question is. It is a bit weak, good sound, but weak. Would it better to replace a perfectly good sub or just add a second one of the same sub?
Also, if I were to add a second sub, how would I do that seeing as I only have 1 LFE output on my receiver?

 

If your sub is 400w and your amplifier is only putting out 50w (examples), a new sub isn't going to sound any better. You might want to think about buying a new amplifier.

 

get another sub(2)

 

Do you really want overpowering bass while you're watching movies? Sounds to me like 100w is more than enough for a home theatre sub. Do you have it tuned right through the receiver?

 

Like most home subs, the TSS450 is self powered. The 450 is pretty under powered. it's advertised as 100 watts, but I doubt it actually produces that much. I'd get a better sub. I personally have an Energy S10.3 sub and it sounds great. If your Infinity is almost enough, the S10.3 might be a bit much. I'd try an ESW-8. It's available through Amazon.com for only $130:

http://www.amazon.com/Energy-ESW-8-Subwoof...4326&sr=8-1

 

I just bought an amp and ran an old bandpass box from my Cougar with 2 10" Volfenhag subs in it. They could be turned down and sound pretty good, or if my neighbors were being annoying in the apartment next to me I could shake the stuff out of their cupboards.