Test Report: Hsu Research VTF-15H Subwoofer Page 2
The sheer bulk of the VTF-15H proved a little difficult to accommodate even in my large listening room. I had to turn it sideways to fit it into my room's "subwoofer sweet spot." Suffice it to say this sub makes no concessions to any lifestyle except that of the hardcore audio enthusiast. (Which IMHO is a fine lifestyle indeed.) Connection was typical; I used the line-level inputs, but speaker-level inputs are also provided.
It's in the adjustments that things get interesting. Besides the usual volume, crossover, and phase controls, the VTF-15H offers three ways to tweak bass performance.
Hsu supplies two foam plugs that can be used to stopper the triangular ports. You can use one plug to reduce port response (and change the box tuning), or both plugs to effectively convert the sub to a sealed-box tuning. The EQ switch offers two positions, EQ1 and EQ2; the former provides deeper bass response while the latter provides more mid-bass output. Combining these two options gives you a total of five different tuning modes, all of which are well explained in the manual. (Using the EQ1 mode with both ports open is strictly forbidden and will void the warranty.)
There's also a Q knob, which adjusts the resonant bandwidth of the subwoofer. The minimum Q of 0.3 gives you a tighter sound (think Yes's Chris Squire or Rush's Geddy Lee); a medium Q setting of 0.5 gives you the flattest response (think the L.A. studio bassists on Steely Dan records); and the maximum setting of 0.7 gives you a fatter sound (think ZZ Top's Dusty Hill or Booker T. and the MG's Duck Dunn).
The changes that all these adjustments facilitate are not subtle. In order to find what works best for you, you'll have to try all the options with a variety of material, a task that took me an hour or two. It's almost like buying six different subwoofers, taking them home, then deciding which among them you like best. The easiest way to find my preferred settings was to put short snippets of DVDs and CDs on repeat, then flip switches, adjust plugs, and note which options sounded best with what.
At some settings, the VTF-15H's brute force overwhelmed me in a way I can't recall experiencing with other subwoofers. To be specific, some settings produced so much punch and power that it started to give me a headache. The 0.3 Q setting in combination with the ports-open mode produced tight bass thuds that felt like being hit in the head with a pillow. On the other hand, you can turn the Q to 0.7, activate the EQ2 mode, and get big, fat, ultra-extended bass that makes you feel like you're sitting on a huge pile of freshly sheared wool.
I greatly preferred the sound with both ports plugged, EQ1 mode activated and a Q setting of 0.5, but that's just me. The point is, it's a pretty sure bet the VTF-15H can deliver bass performance that'll please you, whether your tastes run to Mozart or Michael Bay or somewhere in between.