do I need a subwoofer?

I dont know how your system sounds, but having a 16 inch woofer may provide enough bass response for your requirements. Head off to the nearest electronics store that sells subwoofers that cost as what you plan to spend on , if you feel that the bass from the system is similar to what you have then theres no need to at the moment.

Considering you are posting in a subwoofer forum, I would no doubt most people would say yes. I personally never thought a subwoofer was all that useful until I got good one and was blown away by the improvement in sound quality.

You do have 16" woofers on your fronts which are rather large, but by getting a subwoofer (with its own indvidual amp), you would be relieving your fronts of a lot of the bass duty so it can focus on performing better for higher frequency sounds. In other words, a subwoofer will not only enhance your bass (by a lot), but it would also enhance the rest of your system.

You definitely need a sub. That's actually an 18" woofer, not a 16" (you take the measurement from the outside of the frame, not the inside of the surround). It's also run full range up to 2000 hz in that speaker... It's purpose is simply to be loud.

I would say you actually need new speakers more then a sub. What's your budget? You could possibly get better mains and a sub with deeper bass if its a few hundred at least.

Of course you need a subwoofer, everyone does.....it's just that many don't know it

Those speakers have 15" woofers from I see and the only spec I see is 32hz-20khz but not the spec for the spec. Regardless, they won't dig down as deep as a good sub in any case, so a sub should improve your movie experience to help out with LFE content, and should help with music as well. For a big room like that you might even think dual 12"-15" subs. What's your budget?

Yeah you're right those are 15's, spec sheet was a little fuzzy

For $1k you should definitely replace those speakers and add a sub. Since this is for movies and music a new LCR would be ideal. This is IMO the best deal going, these speakers are regularly double the price.

Boston A360
http://www.accessories4less.com/make-a-store/item/BOSA360WHA/BOSTON-ACOUSTICS-A360-3-Way-Dual-6.5in-Tower-Speaker-Each-White/1.html

Boston A225
http://www.accessories4less.com/make-a-store/item/BOSA225CGB/BOSTON-ACOUSTICS-A225C-2-Way-Center-Channel-Speaker-Black/1.html

I would then get a pair of these JBL's while theyre $180 ea

http://www.newegg.com/Product/Product.aspx?Item=N82E16882665157

Right now you have a mismatched hodge podge system full of cheap components and no sub. Spending $1k on just the sub would get you some very nice bass, but the above components would get you a very nice system for movies and music.

I have to say that those are some of the strangest recommendations I have seen. Especially together as a system.

In one word: YES!

Why?

Because your speakers play only so low and one needs a "SUB-woofer" to go lower and be able to reproduce the lower octaves presents in every movie sound track.

As to advice for a PC based sound system, I'm clueless as I put my effort into quality soundcards and headphones as there's no desk room for a PC based speaker system.

Care to elaborate?

I have full range speakers myself and I have tried many cheap subs and hated them all for music. One thing I noticed (well only in Starwars… only movie I watched in 6.0 and 6.1) is that my receiver does not put the LFE channel into the main speakers in 6.0, the signal is completely lost. So for me a 5.0, 6.0, or 7.0 setup is missing some bass. In most movies a lot of bass comes in the front 3 channels but for some movies I think some bass is different in the LFE channel.

Cheap subs are the problem. Better subs - which cost more - can sound very good with music.

The Kenwoods dig down to ~32Hz., so you could benefit from a subwoofer for movie viewing. Since you're already down to 32Hz, there's no point buying an inexpensive sub that will only get you a couple of Hz lower. IMO, you should consider a sub that will get you down to ~20Hz (or lower). Given your budget of $1,000, that opens up a few solid options:
- PSA XV-15 ($799, shipped)
- HSU VTF-15H ($879 + shipping)

For a little over $1K:
- PSA XS-30 ($1,149, shipped)
- dual SVS SB12-NSDs ($1,149, shipped)

If you like how they sound and how they perform in your space, they're OK. If you don't, they're not.

You are correct. That was my way of saying don't go cheap. I did not gain any low end with my cheap options, just volume. Since a like running everything flat I did not gain anything.

I'm looking into Rythmik right now, I'm a music only guy so Rythmik seems to be a great option as the only subs (i heard) that I liked was a Paradigm Servo 15 v1 and a Rel R-328.

Understood. Rythmik's servo-equipped subs (sealed and ported) seem to have a pretty solid reputation for being "tight" and "accurate".