Well you are kind of talking about two different beasts and are quite different from each other.and the price difference is justified in the differences that are necessary to the proper execution of design and performance with each of these models. Before I go on, I had a VTF-2 MK3 for a while in my office, and thought that is was a decent sub.granted I only used it a low levels. Voucher Code For Your Dom Serial. I doubt I would have liked it in a home theater or under high SPL usage. Obviously the big difference in these being the VTF-3 is a ported design while the ULS-15 is a sealed design. I would look at these measurements of the ULS-15 and read the rest of the review which suggests that dual ULS-15s is the place to start. 15.5% THD at 100db at a 20hz test is fairly high and not a flattering measurement for this sub.(Mind you, that in the first sentence of marketing for this sub on the HSU website, they market it as 'an ultra low distortion subwoofer') In your price range I would be looking at these instead: or perhaps one of these models from Epik. When we measured the ULS-15 in our demo room with mic 1ft away from the cone, THD was less than 5% @ 100db. In the review mentioned above, at the location where the subwoofer was placed, there was a deep bass suckout (ie.

Rocio Jurado Rapidshare. 20Hz was several db lower in level compared to 40-60Hz). This inflates the 2nd and 3rd order harmonic distortion when measuring 20Hz fundamental.

You can even see from the JL F113 review on the website that the in-room frequency response curve is totally different vs the in-room response of the ULS-15, even though both the F113 and ULS-15 have a pretty flat anechoic response from ~20-60Hz. Most people who have listened to the ULS-15 have said it is the cleanest bass they have ever heard, and some of these individuals have listened to very high end and powerful subwoofers that are frequently talked about on the internet. The ULS-15 vs VTF-3 MK3 is a very apples to oranges comparison.