Thus, it should come as little surprise that I would include a few songs from this album in my evaluation of the ULS-15 Mk2 subwoofer, which is Hsu Research’s most musical and “spouse-friendly” sub. It’s diminutive compared to their lauded VTF-15 H and VTF-3 Mk5 HP end table-sized behemoths. Yet, I had read that this sealed subwoofer could really dig deep and rattle the room with startling deft and impact, and I wanted to find out for myself.
Why Hsu Research?
For those unfamiliar with Hsu (pronounced, “shoe”) Research, it was founded in 1991 by Dr. Poh Hsu, who’d received his PhD in civil engineering at MIT. Based out of Anaheim, California, Hsu Research sells their products exclusively via their web site.
Now about a year ago, I had purchased a pair of used Von Schweikert VR-5 HSE speakers, which were extremely natural sounding, but lighter in the bass department than I’d like. Thus began my quest for a good subwoofer.
Having heard that REL made the best subwoofers, I auditioned their T-9 model, which has a pair of 10 inch drivers — one active, one passive. It sounded amazing and I began saving up for the purchase.
Some months had passed when I noticed reviews on subs produced by Hsu Research — most notably the VTF-15 H and VTF-3 Mk5 HP. They were massive with their 15 " woofers (standing 26 and 25" tall, respectively), but at under $1,000 they reportedly put out amazingly powerful and high quality bass. The VTF-15 and 3 models had various tuning options with plugs that allowed the listener to keep their two ports open (for greater loudness) one closed and the other open, or both closed.
Reading these reviews jogged a memory that I’d sublimated regarding the REL T-9: while sounding great, its handling of live rock or blues concerts left me a touch underwhelmed; it lacked that really low end typical in such venues.
I began considering other options, including another brand from Great Britain. However, when it came down to it, they also tended to favor 10 inch woofers like REL and, reading between the lines, seemed to possess that British politeness. I didn’t want polite; I wanted the unblinking truth and and a punch in the stomach, not a pleasant facsimile and a handshake. Hsu had piqued my interest.
I had considered reviewing the VTF-15 H or the VTF-3 Mk3 HP, which Dr. Hsu recommended for my listening space. However, when I told my wife about both models’ dimensions, she balked. She was more amenable to the ULS-15, which, at 19 inches tall, was roughly half a foot shorter than either model.
I discussed the matter with a friend in The Audiophile Group (on Facebook). He asserted that sealed subwoofers are inherently faster and more accurate in rendering music than ported subs (which play louder but take a few mili-seconds longer to recover between bass pulses). A search online seemed to bear this out.
That’s when I took a second look at the ULS-15 Mk2, which was smaller but packed the same driver and amp as its bigger siblings. The more I read, the more I liked the idea. Worst case, I’d send it back following my review.
It was time to act.
Unpacking the Beast
My wife was home when the 85 lb. package arrived on a Friday afternoon and, thankfully, the FedEx driver broke company policy and hoisted it inside the front door for her. Now, the unpacking instructions suggest two men carry it into place, however, as a former weightlifter, when I arrived home, I was fine with carrying it into our living room. I placed it on a thick entry rug, cut the tape holding the top flaps down, and as per directions, turned it upside down and carefully slid the subwoofer out onto the rug. From there, I dragged it the remaining several feet, gingerly raised it off the rug and placed its rubber feet onto our red oak floor.
It’s a heavy, minimalist cube with rounded edges and a black cloth covered grill that attached magnetically. The black semi-gloss finish is attractive and goes well with our decor (for an extra $150, we could have gotten the rosenut veneer finish, but my wife said it wouldn’t go with our room’s colors).
There are several hook-up options with the ULS-15: via XLR (or balanced), high level from the amplifier and low level/sub inputs. Wanting the best synergy with my main speakers, I called Von Schweikert Audio directly and spoke with Albert Von Schweikert (or one of his sons). He told me that the high level option was best and, in fact, was the method they used with subs at all the audio shows. He also swore hooking up simply the left channel made for the cleanest sound and worked fine, as recording engineers usually have their bass panned to center, not left or right (however, a Hsu rep discouraged this practice, as some recordings may have the bass recorded on the right channel and some movies may pan the bass from side to side, depending on the scene). That said, he cautioned me that if my amplifier is bridged, I could destroy my amplifier.
Whereas I’m quite sure my Mark Levinson ML-9 amplifer isn’t bridged ( my audio technician who'd serviced it this last year six months ago couldn't recall, but said he was 99 percent sure it wasn’t), I could not find any documentation online that it was not. This made me nervous. So, I opted for the lower level inputs and made sure the crossover defeat switch was left “on” (in the off position, it allows a preamp/processor to handle the sub crossover duties).
I tweaked the settings on and off for about a month, enjoying my music, movies and HD TV shows more than ever, eventually settling on the Q setting at roughly .6 (it ranges from .3 to .7), the crossover at about 57 Hz and the volume at about 1:30 (the manual stated to start at the 12:00 o’clock position and work from there). Our home audio and theater setup never sounded so good!
It was time to evaluate. Armed with legal pad in hand, I hunkered down for my formal critical listening session.
Frequency response: +/-1 dB 20-200 Hz
Woofer size: 15 inches
Amplifier power: 2000 watts rms short-term, 600 watts continuous
Crossover slope: 30-90 Hz, by-passable
Crossover Type: Linkwitz-Riley, Low Pass Only
Q Control: 0.7-0.3
Inputs: Balanced L/R, unbalanced L/R, speaker level L/R
Dimensions: 19” (H) x 18” (W) X 19.5” (D) with feet, grill and heatsink
Weight: 65 lbs.
$779 for satin black model
$929 for rosenut wood veneer
$69 shipping and handling
· Toshiba Satellite C655 laptop computer with JRiver Media Center, ripped CDs, FLAC and DSD files
· Straight Wire USB Link USB cable
· Lampizator Lite 7 DAC
· Straight Wire Solo interconnects
· Technics SL1200M3D turntable retrofitted with a special replacement RCA cable out from Straightwire, Inc. with Ortofon 2M Blue cartridge
· Schiit SYS passive preamp
· Straight Wire Solo interconnects with CAMAC connectors on one end (to connect to the Mark Levinson amp) and the other with RCA connectors to the preamp
· One pair of AudioQuest Hard Y Adapter (1 Male to 2 Female RCA splitting the SYS output to the amp and the subwoofer)
· Audioquest/Cinemaquest HD-6-X CL3 75Ω Coax Video Cables with ITC-18/RCA gold plated connectors (to the ULS-15 Mk2 subwoofer)
· Samsung Blu Ray Player
· Toslink cable (basic $10 six foot cable)
· Mark Levinson ML-9 amplifier
· Straight Wire SoundStage SC external bi-wire cables
· Von Shweikert VR-5 HSE speakers
The Media Room
My listening and viewing space is a 12’ X 18’ living room with an oversize, 8'x7' window to the right, a smaller corner window at the front left side, an 18' vaulted ceiling, with a adjacent dining room to the left, a hallway behind and a loft space above. Needless to say, that's a lot of open space to pressurize, so the challenge is on for the ULS-15 Mk2!
The Listening Session
“So What.” Larry Carlton. Last Nite. MCA Records, 1987. Vinyl album.
It’s February 17, 1986 at the Baked Potato in North Hollywood, California. With the reels rolling, Carlton takes the smooth jazz gloves off and unleashes a meandering, introspective cascade of notes with his ES-335 electric guitar on this Miles Davis classic. It’s not long before acclaimed sessions bass player, Abraham Laboriel, joins the fray with a playful deft and hint of weightiness, promising good things ahead.
The payoff is almost immediate: Carlton scumbles over scales and chord progressions in masterful improvisation, with Laboriel’s lithe and thick sounding electric bass handling the twists and turns with great aplomb.
So far, so good. The ULS-15 Mk2 blends well with the Von Scweikert VR-5 HSE speakers in bringing this session to life; drummer John Robinson’s kick drum has weight and oomph as Terry Trotter’s keyboards take over solo duties. This is truly how a live recording should sound. The crowd applauds.
“Don’t Give It Up.” Larry Carlton. Last Nite. MCA Records, 1987. Vinyl album.
Robinson’s kick drum, Alex Acuna’s percussion and Laboriel’s bass set the stage, comping off Carlton’s Gibson before he embarks on a frenzied tear. The ULS-15 and the Von Schweikerts mirror the band, cohesive, accurate and fast in reproducing this riveting rock-edged romp. The overdubbed saxophones and trumpet (remixed later at Carlton’s Room 335 home studio) complements Carlton’s fiery and sassy guitar riffs, while Laboriel pounds out the bass line with passion and precision. My face is aglow as Carlton’s final flourish fades and patrons cheer.
“Forty Reasons.” Chad Wackerman. Forty Reasons. CMP Records, 1991. CD ripped to laptop.
Jimmy Johnson’s electric bass ambles in with dark and ominous overtones, full of depth and authority in this gem by the talented polyrhythmic L.A. sessions drummer, Chad Wackerman. With his kick drum counterpoints, Jim Cox’s keyboard and Allan Holdsworth’s minimalist fade-in comping, it’s a catchy start.
Suddenly, Cox explodes into a passionate and frenetic bridge; Wackerman’s toms, cymbals and kick drum sound balanced and amazingly good. Leading into the second verse, the keys set the stage for the mercurial solo of guitar synth guru, Allan Holdsworth, which starts out slowly but builds into an unsettling, but brilliant frenetic fusillade. All the while, the bass, toms, snare, and bass drum keep the vibe slamming.
Holdsworth uncorks a circumspect, slow brewing solo with hints of John Coltrane’s mathematical approach; it builds into a percussive inferno laced with reverb, power and slam.
And, like a thunderstorm passing, Jim Cox’s keyboards play out a melodic if mournful denouement, undergirded by Wackerman’s counterpoint and Johnson’s heavy-footed walking bass. It’s magic.
“Fearless.” Chad Wackerman. Forty Reasons. CMP Records, 1991. CD ripped to laptop.
Like a stripped down top fuel drag racer, this song is all muscle and no fat. It’s essentially a delicious drum solo comped by Holdsworth’s guitar and Johnson’s bass. Toms, snare, bass drum and and a large array of crashing cymbals explode in an orgiastic whir of energy, enhanced with echo and effects that leave one breathless. Wackerman is an immensely talented dude, and Team Von Shcweikert/Hsu delivers his payload across the finish line with checkered flags.
“Quiet Life.” Chad Wackerman. Forty Reasons. CMP Records, 1991. CD ripped to laptop.
In contrast, Johnson’s bass is surprisingly sensitive in a mournful, slow lead comped by Cox’s keyboard, then slides effortlessly into a deep, undergirding rhythmic role as Holdsworth’s guitar takes over in understated fashion.
Re-assuming the lead again, Johnson’s bass is seamlessly portrayed in its delicacy and detail, and when it’s time to play support in the lower octaves to Holdsworth — and later, Cox — his tone is a giant anaconda, alternatively menacing and captivating, as it snakes its way through the tune’s undulations.
The ease of Johnson’s transitions from lighter, fretless bass sounding leads to the massive leaden voicing emanating from the bowels of hell call to mind works by 20th century painter Francis Bacon, whose oils are often built up to several inches thick, but gently taper down to a very thin coating, sometimes revealing the bare linen canvas underneath. These seamless shifts are very well conveyed by the interplay of the ULS-15 and the Von Schweikerts (and the highly acclaimed LampizatOr Lite 7 DAC which, after all, does a sublime job of converting digital music files to analog).
“Shine On You Crazy Diamond.” Pink Floyd. Wish You Were Here. EMI, 1975. CD reissue, ripped to laptop.
Gilmore’s guitar solo introduction is amply supported with the weightiness of Roger Waters’ electric bass and Richard Wright’s keyboards in this classic by the Uber rock group, Pink Floyd. Nick Mason’s drums and kick bass have plenty of oomph, locking in the rhythm and lower end well, while Gilmore’s brilliant and effervescent guitar holds court.
The snare, the toms, high hat and bass drum are tastefully understated but remain a solid presence. The table is set, and now the singing commences. Waters, backed by Gilmore and Wright on vocals come on in their haunting eulogy. Then, Dick Parry’s saxophone solo, like Gilmore’s electric guitar, is three dimensional and well articulated against the thick, dark rhythm section.
“Welcome to the Machine.” Pink Floyd. Wish You Were Here. EMI, 1975. CD reissue, ripped to laptop.
Basking in the afterglow of “Shine On,” I am roused by the rumbling introduction to this celebrated hit. It sounds and feels like a Mack semi-trailer truck backing into my living room, which tremors under the subsonic pressure. I think a couple thousand brain cells just died, the result of being vibrated into a fine jelly.
The rumbling abates as David Gilmore’s vocals take over this highly synthesized dirge. The Synth AKS keys, steel guitar, bass and drums weave an intoxicating trip, enveloping the room in a tsunami of sound. It’s mesmerizing and the ULS-15 really nails the lower octaves in impressive fashion.
“Another Early Autumn.” (up-sampled to DSD via JRiver Media). Jim Ferguson. Not Just Another Pretty Bass. A-Records, 1999. CD ripped to laptop.
This light hued jazz samba by bassist Jim Ferguson (who’s toured with country singer Crystal Gayle as bassist and backup vocalist and served as backup vocalist for the Statler Brothers, Dinah Shore and Tennessee Ernie Ford) brings welcome relief from the previous heavy-handed selections. His upright acoustic bass playing is impeccable and his vocals call to mind Chet Baker. Today’s presentation has plenty of detail, but I’ve never heard his bass hit the lows emanating from the the ULS right now. I’m half tempted to dial back the sub’s volume setting a touch, but quite frankly, I like it.
The interplay between the higher and lower notes of Ferguson’s bass, in juxtaposition with the drums, piano, saxophone and vocal leads are compelling. The bass solo is well crafted; the timbre of the bass in the upper registers are well articulated and defined, but when it slides into the lower octaves (where the ULS takes over) it meshes well and packs plenty of punch for a delightful listen.
“Barra Da Tijuca” (Tijuca Bay)” John Patitucci. GRP Records, 1995. CD ripped to laptop.
The Brazilian influence continues with this gorgeous slow tempo samba showcasing the talents of Patitucci (most noted for his work with Chick Correa’s band) on double bass with Kevyn Lettau’s soprano vocals taking center stage; combined with lilting cymbals, high hat and John Beasley’s piano it makes for a lovely rhythmic ballad. It’s very holographic and natural in its detailed voicing with Michael Shapiro’s drum rim shots and Patitucci’s lower and upper register oscillations. The dialog between his bass and Beasley’s drums is simply outstanding. It’s a thoroughly enjoyable listen as Lettau concludes with her final vocal run, with the rhythm section parlaying an impeccably tight and enchanting support act that, if there was any doubt, aptly underscores the ULS’s ability to blend with the Von Schweikert speakers.
Pearl Harbor. Touchtone Pictures, Jerry Bruckheimer Films and Buena Vista Pictures, 1991. DVD.
This popular World War II movie featuring Ben Afleck and Cuba Gooding, Jr. is rife with explosions and special effects that evoke the childhood wonder of watching fireworks for the first time when replayed with over good home theater equipment, and as a former owner of a pair of large Martin Logan reQuest speakers, I’d really been able to enjoy this show via the two 12 inch woofers anchoring each electrostatic speaker. I sold them to acquire the Von Schweikerts, whose improvements in midrange were superb — yet I missed the lower ended bass extension of the Martin Logans.
Not any more.
A Hsu-nami in My Living Room
The Hsu Research ULS-15 Mk2 subwoofer adds a whole new level of visceral experience to the viewing, as witnessed in the attack sequence at Pearl Harbor. The floor quakes. I feel the guttural growl of plane engines revving, explosions and tectonic rumblings reverberating in my feet, chest and skull. Yet, it’s not unseemly or exaggerated — just real — just like being there.
This is precisely why I picked up the Von Schweikert VR-5 HSE speakers: I wanted that live, in the room feeling. And with the addition of the ULS-15 Mk2, I have that added command of the lower end of the spectrum that I craved.
As I’d previously mentioned, I'd auditioned the REL T-9 subwoofer, and found it very musical and a terrific performer. Yet, that extra level of low extension, that chest slam that you feel at a live rock concert or with explosive action movies was missing. To borrow an expression from Arnold Schwarzenegger, it’s the difference between cologne and sweat. Or, more aptly, it’s the difference between hearing Larry Carlton on a smooth jazz station and witnessing him live in a smoky bar.
Don't get me wrong; the ULS-15 Mk2 handles delicate passages or those demanding speed and accuracy with ease. Bottom line, it really works in my system and is fit company for the likes of Von Schweikert, LampizatOr, and Mark Levinson equipment whether playing music or presenting action movies. Therefore, I am heartily recommending it and buying my review sample.