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Published December 15, 2003



Hsu Research VTF-3 Subwoofer

In the early days of the Internet and mail-order audio equipment, a handful of companies built speakers primarily for direct sale to customers. Many of those firms are no longer with us, but the ones that are have earned reputations over the years for excellent value and customer service. Hsu Research, a pioneer in this market, is no exception -- you’ll find people singing Hsu’s praises all over the Web.

Distribution was not the only area in which Dr. Poh Ser Hsu was a pioneer. His subwoofers were different from all the rest in using as enclosures fiberboard tubes -- actually, cylindrical concrete forms used in the building industry to pour pier footings -- rather than the standard wooden boxes. It was a novel idea, and very successful; the enclosures’ continuously curving sides reduce internal standing waves and resonances. Also, the tubes are lightweight and inexpensive, presumably reducing both manufacturing and shipping costs. On these basic design principles, Dr. Hsu has built a company widely recognized for making high-quality subwoofers at very low prices.

The downside was that not everyone was thrilled with the idea of a big black tube sitting in the corner of the family room. In response, Hsu Research introduced a line of conventional box subwoofers. The subject of this review is one of these, the VTF-3 ($849 USD), which occupies the middle of the line, sandwiched between the smaller VTF-2 and the functionally similar but better-looking rosewood-veneered VTF-3R. All comments about performance should apply equally to the rosewood version.


Unpacking the VTF-3 and moving it into place can be quite a chore. It weighs 93 pounds; you’ll probably need a shower by the time you’re done setting it up. The first thing you’ll note as you unpack it is the black-crinkle paint finish, which some will find attractive and many will not. But don’t rule out the VTF-3 on looks alone -- it has a lot to offer for the money. If you really must have a piece of furniture, look at the VTF-3R.

The physical configuration is standard stuff. The VTF-3 is 15" wide by 20" high by 22" deep; the 12" woofer cone is mounted in the front, and magnetically shielded for placement close to a television. The VTF-3’s frequency response is rated as 18Hz or 22Hz to 125Hz, +/-1dB, depending on the mode (more on that in a bit). The amplifier power is rated at 250W continuous.

Around back are two large ports, the internal amplifier, and the volume and crossover control, the latter variable from 30Hz to 90Hz at 24dB/octave, and bypassable for use with a digital receiver or preamp. The phase switch can be useful in blending the subwoofer with the main speakers. Power is supplied via a heavy IEC power cord; a cheater plug is provided in case you have problems with ground-loop hum -- not all that uncommon, in my experience.

hsu_vtf3_rear.jpg (24226 bytes)While the VTF-3’s construction and appearance may be standard, its acoustic configuration is another story. By use of a supplied foam port plug and a third switch on its rear, the VTF-3 can be configured for either maximum output or lower extension. The operation involves removing or inserting the plug in the appropriate port and setting the Bass Extension Switch to 20Hz or 25Hz. Be careful when doing this -- Hsu Research warns that you can damage the driver by setting the switch incorrectly and playing the sub at high volumes.


Moving this beast into position was an effort. Its size and weight mean that moving it is best done by two people, or by dragging it on a heavy blanket. Once it’s in place, however, you should have little enough reason to move it. One nice bit of customer service is that if you give Hsu Research your room dimensions and a handful of other details about your space, they’ll make suggestions about where to place your sub for the best results. It turned out that one of their suggestions for my large listening room was a good starting point, and required only minor tweaking of position to fine-tune the result. I tried the VTF-3 in maximum output and maximum extension modes in this room and finally settled on maximum output. Though I think I’d have been perfectly happy with either, the VTF-3 was a little more dynamic in this mode.

I used the VTF-3 with Ascend Acoustics CBM-170 speakers, an Onkyo TX-DS696 receiver, and a Sony DVP-NS755V DVD player.


One movie that’s certain to give any subwoofer a workout is Star Wars: Episode II -- Attack of the Clones. As Senator Amidala’s spaceship passes in the opening scene, the VTF-3 shook the room, floor, walls, couch, pictures, doors, and everything else! The dog, which had been sleeping up to this point, sat up and took notice. The cat left the room. My wife, who was in the next room, peeked through the door, wanting to know what had happened. Ditto with the speeder chase through the city after the assassination attempt. The Hsu VTF-3 was as much felt through the seat of the pants as heard.

In U-571, it’s not necessarily how low the bass, but the amount and definition of the bass that are the test of a subwoofer. The VTF-3 excelled, producing deafening results during the famous depth-charge scenes (chapters 15-18). My own sealed subwoofer (I designed and built) starts to complain loudly at these levels, and would soon give up for good if I continued the kind of abuse the VTF-3 was capable of absorbing. Bass definition is also key in this sequence, and the VTF-3 delivered. Many will argue that bass definition is entirely a matter of upper-frequency harmonics, that there’s no such thing as "fast bass." While it’s true that the behavior of your main speakers has a great deal to do with bass definition, the subwoofer itself must react quickly to changes in energy. This requires good control over woofer-cone movement, and that box resonances be kept to a minimum. While this sounds easy enough, it’s no simple task at the energy and cone-excursion levels produced by a high-output subwoofer.


Telarc’s version of Tchaikovsky’s Overture 1812 [Telarc CD-80041] is famous for its ability to test a system’s low-frequency capabilities; that is, it’s famous for frying woofers. The very real, authentic cannon shots are high enough in volume and low enough in frequency to cause lesser speakers to go into thermal meltdown. Warnings all over the album jacket admonish the listener to play the recording at low volume levels until it is ascertained that the speakers in question can handle the output. By the time I got around to running this staple subwoofer test, I was sufficiently convinced of the VTF-3’s fortitude that I let it loose at nearly full scream. The VTF-3 shrugged off the entire exercise with aplomb.

But that was only part of the story. The cannon shots should at once be a slap on the forehead and a swift kick in the rear. At worst, they’ll be indistinct rumbles; better, they’ll startle the unsuspecting listener; best, they’ll startle the listener who already knows what to expect. The VTF-3 fell into the last category.

If you want to check your sub for low-frequency extension, try "Jurassic Lunch," from The Great Fantasy Adventure Album [Telarc CD-80342]. The main energy of the dinosaur footsteps is in the 10-25Hz range. While most subwoofers will reproduce some of the upper-frequency harmonics, only the meanest and nastiest will get the primary frequencies. How can you tell? Well, with the VTF-3 in my room, there are footsteps at the end of this track that I can only just hear, but that shake the room like a slipping fault line. I did some crude measurements and found that I was getting useful output at around 15Hz -- something the rest of the subs in the house could only dream of attaining. There’s not much music out there with this kind of low-frequency information, but for those rare occasions, there’s simply no substitute for a speaker that can deliver the real thing.

If you want to wake the neighbors, the Blue Man Group’s The Complex [Lava 83631-2] is always a good choice. With the VTF-3 as the driving force for the low end, you might be hearing not only from your neighbors, but from their neighbors as well: This is one bass-heavy CD; wimpy wannabe subs need not apply. Though this music will rock the house, the bass is meant to be tight, with tons of impact. It shouldn’t sound like your neighbor’s kid’s car subwoofer. This is especially evident on such tracks as "Persona," on which the bass comes on with definite slam, then slowly decays. A good sub will give you the slam and the nuances of the reverberation of the decay, and the VTF-3 did a marvelous job of it: The initial hit shook the room; as the note decayed, I could hear subtle variations of frequency. To me, that pretty much defines the ideal of a well-designed, well-integrated subwoofer.

I normally eschew the test material that manufacturers occasionally send along. However, the copy of the Boston Audio Society’s Bass Test CD that Hsu Research sent me turned out to be an excellent resource, with five useful tracks of music and several tracks of pink noise, warble tones, and the like for system and room testing. Put "Downward Glide" on repeat and use it to track down all those little bits around the room that are rattling and need to be cushioned. If you buy a VTF-3, you might find this a necessary exercise.


The only subwoofer I had in the house that was comparable to the Hsu VTF-3 was that sealed sub of my own design, which uses ACI’s highly respected (but no longer available) SV-12 driver. The subs are similar in size and weight, and the sound of mine is very clean, with excellent definition and slam. However, that’s where the similarities ended -- in every other respect, the VTF-3 outperformed my sub. Its output was several dB higher, its in-room extension at least 10Hz lower. While both subs sounded great on the vast majority of program material, the VTF-3 provided that little extra when things got really loud and low. Most of the time, I never noticed the difference between the subs, but when I did, the effect was always dramatic. There’s nothing quite like feeling the rumble of an explosion in your rear end before the sound of it hits -- in the subwoofer category, that’s what separates the men from the boys. The Hsu Research VTF-3 ranks as The Man.


The Hsu Research VTF-3 is a killer subwoofer -- there are plenty of subs out there that cost a whole lot more and perform worse. I’ve heard many subs that have clearly been designed strictly for boom and wow effects for movies. Unfortunately, such subs sound horrible with music and shouldn’t be considered for mixed-use systems. In a movie-only system, the VTF-3 will provide more accurate reproduction of effects than those subs ever will.

Few subwoofers on the market today offer the combination of output, extension, and versatility of the Hsu Research VTF-3. The VTF-3 isn’t that much more expensive than many so-called budget subs, and it sounds far better than many far more expensive ones.

...Jeff Van Dyne

Price of equipment reviewed

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