Originally Posted by
handsaw 
Just purchased 2 used VTF15s. They sound incredible. I had a hard time at first integrating them with my other speakers, I was reluctant to turn them down at first but the reality is that there is so much output I had to. Once I came to my senses they blended nicely.
I have one these placed at the front of the room laying on its side between the right and center speaker and one at the back in the mirror image position under the foosball table (it barely fit under it laying on its side).
My room is 16 by 24 with a cathedral ceiling and it opens on the left rear to the kitchen/dining room which is about 12 by 16. I figure the total volume is around 6100 cubic feet.
My other speakers are...
Klipsch RS62II mains
Klipsch RC62 center
Klipsch RS 3 surrounds
Polk bookshelfs rear surrounds
Old sub - you dont want to know
Yamaha 667 Receiver
Epson 8350 Projector
Severtson 106" screen
I have my receiver cross over set to 80 hz. The subwoofer at the front has both ports plugged, the crossover set to out and Q around 5. The sub in the back is set to both ports open, crossover enabled and set to 40 hz and Q around 3.
The sub settings are not likely final but after working with this setup for a few hours it is pretty balanced for both music and theater. I calibrated using my ears and several concert videos. Music seemed to work better for calibrating since there is constant low frequency material and it is much easier to hear when things become un-natural. After I had this sub set I blended in the rear one to get the bottom end of the kick drum which then required almost no additional tweaking for excellent movie end sound.
I think I would have been able to get great sound with a single VTF15 but it probably would have taken more attention to placement and more time tweaking settings.
The single sub up front blends seamlessly with my Klipsch mains and you can hear EVERY note the bass guitar player plays with clarity and authority. The kick drum sounds good without the second sub but blending in the second sub crossed over at the lower frequency makes it pound without any hint of muddiness. My theory is that having each sub address a slightly different part of the subwoofer spectrum allows me to balance between them to achieve the smoothest aggregate performance. This is especially important since I dont have any subwoofer frequency correction available on my receiver.
I may be sacrificing a bit of overall output doing this (but maybe not...) but there is so much output available this is no issue at all. These subs are loud enough to make you uncomfortable if listened to for an extended period of time so any worries anyone has about volume in a room similarly sized to mine are unfounded.
I went to bed before my boys and they finished watching a movie. In my bedroom it was strange because I couldn't hear a significant amount of bass but every metal object in my room kept vibrating. This was after I turned down the overall volume a bit before going to bed.
In a prior time of life I worked with pro audio for both live performance and installations so I would think that this past experience gives me additional perspective the average home audio enthusiast may not have when it comes to evaluating the quality of these subs. I only mention this because I hope to make clear that these subs deserve consideration.
My comments overall:
Excellent build quality
-Innovative and well executed design for maximum flexibility
-Very high output - your listening environment will complain before they do -(my foosball table playing surface vibrates all the time now and I have never heard a sound from it before these subs)
-Very accurate reproduction across the low frequency spectrum including very low frequency.
-Excellent customer service - the prior owner had lost two of the port plugs as well as the disks that originally came with these subs - HSU is fedexing free replacements directly to me at the original owners request and was shipped before we even completed the transaction. AWESOME
-The only real issue I can see at this point is that I would prefer the amplifier controls etc were recessed to protect them. An object this large and heavy bumped into something would be very unforgiving to anything sticking out. This wouldnt have been a significant burden in the design process but could be a finishing touch to an overall excellent design.
These forums are as dangerous as they are beneficial. So many of the products discussed would be a good choice for anyone but we all agonize over small differences trying to make a 'perfect' decision. I suspect most subwoofers in this class/price range will meet ALL the needs of 99.9% of the population. With that said, I can CONFIRM that the VTF 15 will meet those needs! I cant say enough how impressed I am with the VTF 15.
Now, how does one go about stabilizing a foosball table to eliminate vibration?