You've narrowed it down to some terrific choices! I've listened to the Rythmik F12, Rythmik F15, Hsu VTF-3 mk3, and VTF-15H (I own the latter 2 but enjoyed listening to all 4). I agree with many of the posts here that mention that a ported sub (i.e. VTF-15H) would be your best bet in a room your size with an 80% HT/20% Music listening preference. Below are my listening impressions of the VTF-15H that I posted on the "New HSU sub revealed today..VTF-15H" thread. On that same thread I also compare the VTF-3 with the VTF-15H.
I haven't heard the Rythmik FV15 (vented/ported), but if you were to go the Rythmik route, that's what I would pick based on your room size and listening preferences.
Okay. I'm not sure the pictures were attached to this, but this is one amazing subwoofer. I'm from the San Francisco Bay Area and I visited some friends down in So. Cal. and stopped by the HSU Open House last week and was impressed by the output and musicality of this big ported sub.
I previously had a VTF-3 mk3 and loved it. I'm mostly HT in my living room (80%/20%) and do most of my music listening in my car, in which I have a sealed J.L. Audio 10" stealthbox in my S2000. I've also listened to and was impressed by a Rythmik F15 (although I didn't get to test it with home theater). So basically, I'm a fan of sealed subwoofers for music and ported subwoofers for home theater.
That being said, I put this thing through the paces and was impressed in both modes. With both ports open, I'm getting a pretty flat response down to 16 hz. in my 4200 ^3 ft. living room. For both ports being open, the sub was very musical (articulate, full, clean sound, and pretty good attack and decay). I played tracks with deep and fast hitting bass from B.O.B. -The Adventures of Bobby Ray, Linkin Park - A Thousand Suns, and Black Eyed Peas - The E.N.D. I also threw in some Saint Saens Organ Symphony #3. The sub kept up pretty nicely with my Ascend Sierra 1's.
In H.T. I was blown away! The bass was definitely present, but in a clean, distinct, impactful way that made movie-watching fun. It played the bass line in the music during Toy Story very smoothly, but was also able to quickly and emphatically add weight and volume to scenes such as when the t-rex toy jumped without overhang (clean, voluminous, tactile). The same can be said of movies such as How to Train Your Dragon, Terminator: Salvation, The Hulk, and the Dark Knight. The great thing about this sub is the added mid-upper bass impact. Nice and punchy!
I also tried sealed mode, and preferred this when listening to music. Adjusting for output differences using a Radio Shack SPL meter, the sealed mode seemed to tighten, clean, and punctuate the bass more (basically sealed subwoofer sound). Movies even sounded pretty good in sealed mode using the max extension setting. However, to me, movie watching was more enjoyable in the maximum output mode with both ports open.
This is one amazing sub, especially when one considers the price! If you have the room for this thing and are considering a sub, this would be a fantastic way to go! The great thing is the ability to go between ported and sealed and use different settings for both to dial in your sound preference.
I'm definitely glad I got this and will do more music listening and movie watching over the Thanksgiving holiday.
Click image for larger version Name: HT.jpg Views: 151 Size: 65.6 KB ID: 191144 Click image for larger version Name: Closeup.jpg Views: 143 Size: 52.3 KB ID: 191145 Click image for larger version Name: nogrill.jpg Views: 151 Size: 47.9 KB ID: 191146