- Manufacturer & Model
- HSU Research ULS-15 MK2 Subwoofer
- MSRP
- $779 (Satin Black, reviewed), $929 (Real Wood Veneer, Rosenut)
- Highlights
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Excellent sound quality and deep bass capability, manageable size and weight, imposing 15-inch driver and 600 Watt BASH amplifier, effective onboard sound quality controls, plays well with music as well as movies, high-quality fit and finish, attractive price point.
- Summary
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The ULS-15 MK2 subwoofer is HSU Research’s only true sealed design, sporting a gorgeous 15-inch driver powered by a 600 Watt BASH amplifier. It’s high-quality finish and customer-friendly size make it easy to place in nearly any room. The included Q and EQ controls make for simple integration, boosting usability for owners that are less technically inclined. Overall performance is excellent, highlighted by killer low frequency capabilities and tight reactive bass. Considering the ULS-15 MK’s generous price point and 30-day return policy, this is a sub that’s easy to recommend.
For a limited time, AV NIRVANA is hosting a Giveaway Contest for a FREE HSU ULS-15 MK2 Subwoofer! Click here to learn how to win.
Experts say the first step to recovery is admitting there’s a problem. But in this particular circumstance, I admit nothing because recovery is the furthest thing from my mind. I will, however, share a little secret with you: I’m addicted to bass.
Like many enthusiasts, my first home theater system featured a woefully underpowered subwoofer. It took roughly a month to realize my hard-earned money had been poorly spent, punctuated by a rather embarrassing demo session that left my new pride and joy shamefully submitting to the demands of a hard-hitting film clip in the presence of a curious friend. It took another month to convince my better half that a new sub wasn’t just needed, it was a life or death necessity. And after promising to make a smart and fiscally responsible upgrade, I quickly found myself on a one-way journey down the low-end rabbit hole.
Some 15 years and eight-plus subwoofer purchases later, I can confidently say I’ve learned quite a bit during my journey to find great bass. First, capable bass performance is in fact a necessity. Second, capable bass performance doesn’t come cheap. And third, there’s no shame in housing some 460-pounds of foundation-cracking subsonic boxes in your home theater room. I only share this knowledge because both points one and two are completely pertinent to this review. After all, lots of enthusiasts yearn for smile inducing bass and most would like to spend as little as possible to acquire it. But that’s the trick, right? Finding the illusive sweet spot between value and true performance in the low frequency realm. It just so happens that HSU’s remarkable ULS-15 MK2 fits the bill, and is likely the perfect answer for a large segment of enthusiasts.
Born From Quality
Ask any enthusiast to rattle off a list of reputable subwoofer brands, and the name “HSU” will undoubtedly be mentioned. Founded by Dr. Poh Hsu, HSU Research has specialized in thoughtfully engineered subwoofers for nearly three full decades. The company originally emerged in 1991 when it offered a cylindrical shaped subwoofer (dubbed a sono-tube), using mail order to reach customers. It has since remained one of the segment’s oldest Internet Direct brands, continually striking an amazing balance between price and performance that’s topped with a sterling reputation.
HSU currently offers five different subwoofer models ranging from its entry level VTF-1 MK3 ($399) to its top-of-the-line VTF-15H MK2 (starting at $899). The ULS-15 MK2 (subject of this review) stands as the company’s lone sealed design, priced at $779 (Satin Black) and $929 (Rosenut), with the option to buy dual ULS-15 MK2s for $1,499 or $1,799 respectively. Originally released last year, the MK2 version of the ULS-15 offers more power and performance controls over its predecessor. It also offers a lower price.
Lower price, you say?
Yes folks, HSU’s pricing never strays from being customer friendly. And because many of its new sub designs have commonalities in componentry, the company has leveraged economies of scale to deliver a retooled ULS-15 model that costs $300 less than the original design.
That deserves a round of applause.
The Walk Around
Weighing 65-pounds, the ULS-15 MK2 is just manageable enough for a single person to lift and carry without requiring a recovery period involving gobs of Advil and a heating pad. Helping matters are the sub’s physical dimensions, which equate to an 18-inch cube (19-in H x 18-in W x 19-1/2-in D with grill, feet, and amp), and large rubber feet that are firmly married to its underside. Not only is it relatively easy to carry, but its overall size allows it to be incredibly room friendly as well. That makes it a great candidate for high traffic rooms or situations where space is limited.
The cabinet is constructed with 3/4-in MDF (1-1/2-in front baffle), and our review sample arrived finished with HSU’s attractive Satin Black coating. A simple knuckle-wrap on the sub’s exterior produces a relatively muted thud, and overall craftsmanship is excellent. The sub’s rounded corners and seamless edges are physical feature highlights, adding a touch of styling that makes the ULS-15 MK2 look great to the eye.
The speaker houses a 15-in front firing woofer that’s covered by a magnetically attached cloth grille. The grille is noteworthy because it snaps into perfect alignment with the cabinet’s edges when positioned over the driver, making for a super clean appearance. When removed, the driver’s rather potent disposition is exposed, amplified by its glossy concave center and robust surround materials.
(HSU Research)
The backside of the MK2 houses a BASH plate amplifier that’s capable of delivering 600 Watts of continuous power (2000 Watts peak) and offers a plethora of controls. To begin, it carries three different modes of connection: balanced stereo XLR inputs, dual high-level speaker inputs, and two RCA inputs. Moving across the top, you’ll find a volume control, phase switch (0 to 180 degrees), operating mode selector (EQ1 and EQ2), Q Control (0.3 to 0.7), crossover frequency knob, crossover selector (In or Out), and a three-way power mode switch (On, Auto, and Off). Below the large heatsink is a voltage selection rocker switch (120 or 240 volts), a fuse holder, and a basic power cord connection.
HSU Research says the ULS-15 MK2 is capable of delivering usable bass down to 20 Hz (+/- 1 dB), which is impressive considering the sub’s overall size. As you’ll see, I found it’s in-room performance more than matched that claim.
Operational Features
One of the ULS-15 MK2’s more attractive features is its ability to serve as a sub for users that have the gear and knowhow to apply outboard electronic EQ, while also offering less technically equipped customers simple fine tuning controls that can lead to radically better sound.
The included Q control knob can be set between 0.3 and 0.7, helping to compensate for various room sizes. The lowest setting delivers the highest mid-bass head room for any sized room and the flattest low-bass response in small to medium sized rooms. The larger your room, the higher you’ll want to set the Q control, with 0.7 meant to be selected for the largest of rooms.
There’s also a switch selectable EQ control that allows owners to choose from one of two operating modes. The “EQ1” mode directs the subwoofer to deliver the flattest deep bass response possible, while “EQ2” trims output on frequencies below 40 Hz. In essence, EQ2 is designed to allow the ULS-15 MK2 to be used as a mid-bass module, but it also can help tame bass that’s overly bloated or boomy.
To illustrate the utility of the sub’s output controls, I recruited Room EQ Wizard to record in-room measurements of the MK2 running in various EQ and Q modes (microphone placed at the MLP). The resulting measurements mirrored each other across Q settings of 0.3, 0.5, and 0.7, with the selectable EQ mode having a repeatable impact on deep bass output. For example, the graph (below) shows measurements taken while operating at Q 0.5. The green line illustrates the sub’s measured output in EQ1, while the red line shows the impact of engaging EQ2. The blue line illustrates the additional impact of external parametric equalization on the sub’s output while operating under Q 0.5 with EQ2 engaged.
In-room EQ Control Demo: Green = Q 0.5, EQ1, Red = Q 0.5, EQ2, Blue = Q 0.5, EQ2 plus external EQ
These measurements demonstrate the value of the MK2’s EQ modes, highlighting EQ2’s ability to serve as an effective trim tool for owners experiencing bottom heavy bass; a simple flick of the switch and the sub’s onboard processing can tame low-end unpleasantries. This is huge for owners that are looking for simple-to-use integration controls.
Out Of The Box
Like other HSU Research gear I’ve reviewed, the ULS-15 MK2’s packaging was fit for the task and delivered the sub in pristine condition. The sub shipped protectively housed in a box within a box, and I found the entire unboxing process to be a simple one-person job. You can watch a video of the ULS-15 MK emerging from its packaging by clicking on the video link below.
Items shipped with the sub included an unboxing guide, a detailed 12-page manual that’s loaded with installation tips and trouble-shooting solutions, a simple graphics driven quick set-up guide, and a standard power cord. The ULS-15 MK2 currently carries a seven-year warranty for materials and workmanship (two-years for the amplifier), with terms and conditions clearly identified in the final pages of the manual.
Set Up
As mentioned, the ULS-15 MK2 is sized to be manageable. While some may find it easier to borrow a friend to help with carrying and positioning, I was able to lift and haul the sub down a flight of stairs to my dedicated 2000-cubic foot home theater room. The MK2 was placed in the room’s front left corner (roughly 18-in from the room’s left side wall). Following 30 hours of break-in, calibration, and equalization, the sub (settings: Q 0.5, EQ 1) sounded phenomenal, with an added bite of low-end heat that my ears typically enjoy.
Post-calibration, Q 0.5, EQ1
I mated the sub with a stereo pair of HSU’s fantastic CCB-8 speakers (external crossover: 80 Hz). These speakers were reviewed last month (click here for the full review), and I enjoyed the opportunity to listen to them again. When setup correctly (an aggressive toe-in that allows for off axis listening), the amount of detail and rich stereo imaging issued by the CCB-8 is staggering. Definitely a speaker that’s worth your attention. Other associated equipment included Yamaha’s AVENTAGE RX-A3070 (read review), OPPO’s UDP-205 (read review), and a Behringer Feedback Destroyer 1124p.
Listening Impressions
(Paramount Pictures)
Now for the fun part: taking the ULS-15 MK2 for a test drive down a road into the depths of subterranean of sound.
I’m no stranger to sealed subs and have found they play particularly well to my ears. As the above post-calibration measurement illustrates, room gain helped to promote plenty of performance from the MK2 below the 20 Hz mark (note: this is specific to my room, another setting may produce different results). The sub consistently issued incredibly confident bass and never hinted at wilting when pushed to reference levels. And while it certainly had zero issue exerting its presence with relative ease, the MK2’s output was highlighted by bass that was alive and exacting. Transients were crisp and I found its tonality to be natural and uncolored.
One of the great joys of integrating new gear is deciding how to challenge it first. Feeling rather spunky, I opened my listening sessions by introducing the MK2 to Skrillex’s debut album: Recess (CD). DJ Sonny Moore’s Recess tracks are the musical equivalent of CrossFit for a sub, presenting layered and torturously deep bass that dish a relentless attack. “All Is Fair” led the MK2 into a world of eye popping driver excursion, with both quick and elongated bass notes pulsating into the room. The track’s demands were devoured by the MK2 and the sub delivered an incredible performance without breaking a sweat. “Recess” seemed to make the MK2 grin as it powered through the track’s rhythm, filling my theater room with beautifully tuned low frequency terror. Then there was “Stranger,” which had the ULS-15 MK2 delivering couch thumping pulses of bass that sounded full and complete (not cut short or inhibited).
While tapping Skrillex was intended to test the extreme musical bass capabilities of the ULS-15 MK2, it’s worth mentioning that the accompanying CCB-8 speakers delivered an equally impressive show. Imaging was off the charts as mid and high frequencies appeared to climb the walls around my listening position. In fact, “Stranger” was a highlight demo track for both the sub and speakers, and one that had my finger hitting repeat on the remote. The seamless marriage of the MK2 and the CCB-8s was mesmerizing, and the trio of speakers worked in unison to paint an audio image that transfixed my ears.
Next, I turned to The Chainsmokers’ Inside Out EP (CD) and Yello’s 2009 album entitled Touch (CD). Both discs offer slightly tamer takes on electronica as compared to Skrillex’s approach. My ears were treated to smooth and elongated bass notes that the MK2 delivered with precision, and tighter bursts of bass that presented with a quickness and sharpness that kept them in step with various songs’ up-tempo beats. And the sub wasn’t shy about being taken to ear-crushing levels of volume; I was never able to find a tolerable volume level that caused the MK2’s composure to falter.
To test the ULS-15 MK2’s refined musical side, I reached for a demo disc furnished by HSU Research for use with its CCB-8 speakers. Listening to Abdulah Ibrahim’s ”Calypso Minor” resulted in a confident bassline loaded with character and spunk, sparkling with clear definition that blended perfectly with the song’s sharp spirts of horns and piano. And Henri Mancini’s familiar “The Pink Panther Theme” gave the sub peppy bass to chew on, which it regurgitated with transfixing detail.
Moving on to movies, I selected three films known for brutally deep bass: Interstellar, War of the Worlds, and Transformers Dark of the Moon. While the ULS-15 MK2 kept me entertained with its impressive musical prowess, I was ready to push the sub to its outer limits with powerful explosions, rocket engines, and the raw impact of Hollywood’s trademark special effects.
Interstellar’s early film rocket launch sequence literally sent my home theater rumbling into orbit, rattling the very core of my room’s walls as glorious waves of deep bass massaged my entire body. Once in space, subtle thumps associated with the ship’s maneuvering rockets sounded precise and abrupt. But the film’s most iconic subwoofer moments (the crew entering the worm hole and Cooper entering the black hole) were the best proving grounds for the ULS-15 MK2. Both scenes have infrasonic material capable of devouring lesser drivers. The MK2 was more than able to tackle the film’s demands, and the resulting bass-laden audio show was on par with performance characteristics associated with my reference system. The intensity of the black hole scene was especially noteworthy, as the MK2’s clean low end effortlessly extended without distorting or inhibiting output with audible noise.
Next up was War of the Worlds, which is widely recognized for its incredible bass heavy “pod emergence scene.” As the scene progressed, the ULS-15 MK2 stood tall for the challenge. Ultra-low frequencies crackled as the sub pounded my theater room with clean output, sending shockwaves through my couch. The low-frequency hums of the pod’s engines were smooth and delicious, as were the thunderous thuds of destruction as surrounding buildings split and cracked into rubble. And of note, the MK2 revealed a particularly challenging low frequency dip that’s present once the pod is standing upright and ready for battle. It was an absolute delight to experience and a big performance checkmark for the MK2.
Last but not least, Transformers: Dark of the Moon took its turn with the ULS-15 MK2. The film’s highlight bass attack (Chapter 17) is one of my favorite demo testing scenes. The MK2 unleashed venomous output, sending blasts of gunfire and pulsating explosions through my chest. The roar of engines and the incredible heartbeat sound as paratroopers jumped from their damaged Osprey pounded my theater room to deep and controlled levels. And the chaos reached reference levels as a skyscraper came crashing down. Time to call my home owner’s insurance...the foundation of my home may have cracked! The ULS-15 MK2 delivered an impressive performance for the duration of this challenging clip, complementing the film’s dynamic audio with matched and powerful bass. Truly impressive!
Conclusion
(HSU Research)
From a buyer’s perspective, HSU Research’s ULS-15 MK2 is desirable on a number of levels. It carries a middle ground price tag, it’s sized right for easy room integration, it has impressive output specs, and is backed by a company with decades of experience and a five-star reputation.
That leaves one rather large question: how does it actually perform?
Demo sessions executed in my medium-sized room point to one simple answer: Excellent. The ULS-15 MK2 knocked my socks off and left me thoroughly impressed. In fact, it’s a sub that I’d purchase if I were in the market for new gear.
The ULS-15 MK2 is capable of staggering output at reference levels, all the while remaining composed and highly detailed. My listening sessions were loaded with accurate bass that was tight and controlled, and I never felt the sub was incapable of meeting the demands of demo material. Add to that an attractive cabinet and plentiful integration controls, and the ULS-15 MK2 is an absolute steal. You’ll be hard pressed to find similar performance in the sub-$800 category, making the ULS-15 MK2 a highly recommended buy.
For a limited time, AV NIRVANA is hosting a Giveaway Contest for a FREE HSU ULS-15 MK2 Subwoofer! Click here to learn how to win.
ULS-15 MK Subwoofer Specifications
- Amplifier Power (RMS): 2000 W Short Term, 600 W Continuous
- Frequency Response: 20 - 200 Hz, +/-1 dB
- Woofer: 15 Inch
- Q Control Range: 0.3 - 0.7
- Crossover Slope: 24 dB/Oct
- Phase: 0°/180°
- Inputs: Balanced XLR (2), Line Level (2), Speaker Level (2)
- Power Outlet Requirement: 720 W, 120/240V
- Enclosure Dimensions: 18" H x 18" W x 18" D
- Dimensions with Grill, Feet & Amp: 19" H x 18" W x 191⁄2"D
- Weight: 65 lbs
- Warranty: 7-years on Woofer, 2-years on Electronics
- Designed and Engineered in the U.S.A.
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I'm hoping to be flat to something like 10 Hz or so.
