The Hsu Research VTF-1 MK2 is, hands down, the best-sounding affordable subwoofer I've heard to date.
It was designed by Poh Hsu and I have fond memories of the first time I met him, at a Consumer Electronics Show in the late 1990s. He had a room filled with subs and a single pair of tiny speakers hooked up to an inexpensive receiver. He played a short series of music pieces with thundering bass drums, mighty organs, and hard-hitting rock bands, and those baby speakers sounded like heavyweight towers. It was a great 2-minute demo, and when it was over I could barely catch my breath, but the first thing I said as I pointed to the wall of subs sitting behind the speakers was, "That's amazing, which subs were playing?" Hsu just smiled and said, "None of them," and glanced over to the sub that was right next to me. I hadn't even noticed it.
That's one of the things you should expect from any great sub; you should never be aware that it's making bass, the sound should appear to come from the speakers. That's easier to do with bigger speakers, because the sub is only contributing the deepest bass notes, but with really small speakers the sub also supplies higher frequencies that we localize with our ears. You start to hear the sub as a separate sound source, which is why it's sometimes best to keep the sub within a few feet of the front speakers in a home theater. Or use the Hsu method, and sit as close as possible to the sub.
The Hsu Research VTF-1 MK2 ($449) is one of Hsu's least expensive models in the 10-subwoofer line -- prices range from $299 to $2,299. The VTF-1 MK2 has a 10-inch woofer on its bottom panel and a built-in 200-watt amp. The sub is sold directly from Hsu Research with a 30-day money-back policy and a seven-year warranty. It's not small or demure, no; the satin-black-finished sub at 18x14x17 inches was bigger than any other sub I had on hand in the CNET listening room, but it sounded more powerful, made much deeper and more precisely delineated bass than the others. No little sub can match what a well-designed larger sub can do. With subs, size definitely matters.
The rear panel hosts a set of sound-tailoring features rarely equaled on subs that sell for two or three times the VTF-1 MK2's price. Some folks want fat bass, some want tightly defined bass, some buyers want to feel the room shake, other want to only be aware of the subwoofer when the movie or music has deep bass passages.
The VTF-1 MK2 can be fine-tuned to deliver the type of bass you want. It has two large bass ports on its rear panel, which when you unbox the sub are sealed tight with large rubber plugs. You can change the VTF-1 MK2's sound by taking one or two plugs out, or leaving both in, and by adjusting the "EQ" and "Q" controls on the rear panel. You can have rich, very full bass or lean, highly defined bass, or anything in between. I prefer cleanly defined bass, as with music I want to hear the pitch of the bass note rather than just a bloated bass sound.
I listened to the VTF-1 MK2 with Hsu HB-1 satellite and HC-1 center speakers and a Hsu speaker/subwoofer system soon on this blog), and also in a 2.1-channel system with a pair of tower speakers ($260 a pair). In both cases it was easy to achieve seamless integration between the sub and speakers. The VTF-1 MK2 reproduces the deepest, lowest-frequency sounds with more authority than the Aperion Bravus 8D sub I usually run in the CNET room, and that sub has one 8-inch active woofer and two passive 8-inch woofers versus the VTF-1 MK2's single 10-inch driver.receiver (I'll cover the complete, six-piece $1,159
The VTF-1 MK2 added a more visceral kick to movies and music, and it wasn't just that the bass went deeper, the speakers' soft-to-loud dynamics were more lifelike. I heard subtleties in the bass, textures, and details in the extreme lows that go unnoticed with other subs. In other words, the system sounded like a much more expensive and larger system. That was especially true when I paired the sub with the Pioneer towers. They sound fine on their own without a sub, but adding the VTF-1 MK2 dramatically opened up the sound. The Pioneers sounded better than many $1,200 speakers. The VTF-1 MK2's low-end prowess plus the speakers' highly transparent sound was a winning combination.