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Hsu Research ULS-15 mk2 Subwoofer Conclusion

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33_ULS_mk2_2.jpgOne way my thoughts on the ULS-15 mk2 can be summed up is that I am sad to have to send my review sample back. If I didn’t already have so much subwoofage, I might have purchased my review unit. There is so little to complain about, and so much to praise with the ULS-15 mk2. Nonetheless, I will get the criticisms out of the way before moving onto the compliments.

The chief criticism I have of the ULS-15 mk2 is the potential for misuse of the EQ1 mode. The reader will recall that the EQ1 mode makes the frequency response flat down to 20 Hz with a steep drop-off below that. That can be a benefit in situations where room gain does not shore up the low end, but the problem is that in large rooms or open areas, and the subwoofer is more likely to be played very loud. This can end up being very taxing on the driver in the boosted frequency ranges in the EQ1 mode, and the sub can quickly reach its limits if played too loudly in this frequency band. We can see the consequence of that in the distortion sweeps in the 15 to 25 Hz band. While the sub can survive that kind of use in short bursts, you definitely do not want to push it that hard very frequently. I would only recommend the EQ1 mode in either near-field use or in large open areas with the stipulation that the subwoofer isn’t going to be played loudly below 30 Hz or so. The EQ2 mode has a lot more headroom, so if you want to blast content that has deep bass, use EQ2 mode. Those who want big-time headroom at 20 Hz would do better by looking at the ULS-15 mk2’s ported siblings, the VTF3 mk5 and VTF15h mk2.

A minor criticism I have of the ULS-15 mk2 is that the slope in EQ1 mode becomes a bit steep at the bottom due to a subsonic filter, and a shallower slope would be able to take greater advantage of room gain. However, this criticism also leads to some praise; the steeper nature of the rolloff helps protect the driver. In all of our testing, we were never able to get the driver to bottom out. We were able to push it past its linear excursion, but we never heard any noises that indicated the sub was in danger in either EQ mode, and our testing procedures pushes the driver very hard, much more so than most ordinary users ever would. I am not saying it’s impossible to bottom out the ULS-15 mk2, but that if it is possible, it is very difficult to do so; you would really have to make a point of doing it. One factor in this might be that since our review sample is new, the suspension might be a bit tighter than a unit that has been in heavy use for a long time, but even so, the ULS-15 mk2 looks to be very well protected against damage from the driver reaching its mechanical limit.

Now let’s briefly go over some of th34_ULS_mk2_cone.jpge highlights of the ULS-15 mk2. Its sound quality is superb, and the high fidelity that was heard in the listening sessions were confirmed by the measurements. The ULS-15 mk2 is a very accurate subwoofer and demonstrated highly linear behavior across a slew of different measurements. The output is tremendous for a sealed subwoofer at this price point, and this sub qualifies for Audioholics’ Bassaholic ‘large’ room size rating (in other words it should be able to meet the target 115 dB peak in seating positions in a 3000 ft^3 to 5000 ft^3 room). The tremendous output can be gleaned from the burst tests and compression sweep measurements, but nothing is as convincing as sitting cross-legged on the floor with the ULS right behind you only a couple inches away, and then cranking a hard dubstep tune to reference level on the AVR. Do that and you will know what a punching bag feels like.

bassaholic-master-large.jpeg

35_ULS_mk2_outdoors.jpgAnother admirable trait is the appearance, a slick satin black or Rosewood veneer with a gleaming concave cone- no way am I hiding that cone behind a grille. The manageable size and weight certainly deserve mention as well; this is a sub that does not take two people to move around. One person of average build can carry the 65 lbs ULS-15 mk2 around without too much of a strain. Since the enclosure is just an 18” cube, it does not eat up a lot of room. Some people might not consider that a small sub, but for the firepower it packs, it is remarkably small. Another point for the ULS-15 mk2 is that its amplifier has a lot of flexibility for different setups, so this is a subwoofer that can be integrated into a variety of systems, and with its adjustable response, its sound can be tailored to suit a variety of tastes.

Outside of the subwoofer itself is Hsu’s reputation for great customer service, a reputation established over many years. Packaging is, as was discussed before, exemplary, so if you ever had to ship it somewhere, you are covered if you hold on to the packaging. The warranty is not bad, but not great; 2 years on the amplifier and 7 years on the driver. An extended 5-year warranty on the amp can be purchased for an additional $90. And that brings us to one of the major high points of the Hsu ULS-15 mk2, the cost: $779 with a $69 shipping fee for shipping within the continental USA. $848 is not inexpensive (to most of us anyway), but if it is compared to many other subs in the Audioholics Bassaholic data compilation, it can be seen to punch way above its price point. When you consider all of the other assets it brings to the table such as its tasteful finish, manageable size and weight, and great customer service from Hsu, it has to be considered one of the top bargains in subwoofers to date.

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
MetricRating
Bass ExtensionStarStarStarStar
Bass AccuracyStarStarStarStarStar
Build QualityStarStarStarStar
Fit and FinishStarStarStarStar
Ergonomics & UsabilityStarStarStarStarStar
FeaturesStarStarStarStar
Dynamic RangeStarStarStarStarStar
PerformanceStarStarStarStarStar
ValueStarStarStarStarStar
Attached Files
About the author:

James Larson is Audioholics' primary loudspeaker and subwoofer reviewer on account of his deep knowledge of loudspeaker functioning and performance and also his overall enthusiasm toward moving the state of audio science forward.

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Recent Forum Posts:

Epsonfan posts on September 06, 2020 13:18
Too many commie China loving libtards here who sold their souls to communist China just like Obiden , NBA and Hollywood.
BRAC posts on May 27, 2020 14:20
Awe
shadyJ, post: 1393701, member: 20472
Both are terrific subs. I think the Hsu subs are a bit more capable in deep bass and the Dynamo subs are a bit more capable in mid-bass. The Dynamo subs have a more sophisticated feature set and amplifier but the Hsu sub has a bit more robust driver. I would say that if you are connecting the sub to a system that doesn't have much in the way of bass management, go for the Dynamo since it has far more ways to control the performance. If you are hooking the sub up to a processor that does have a lot of bass management features, the Hsu sub may make more sense since it offers a bit more raw performance overall. But the Dynamo sub isn't that far from the ULS-15's performance.
Awesome. Really appreciate the help. I’m actually one of the few that prefers mid bass over deep bass for movies. Deep bass excites WAY too many rattles and vibrations in my room. Can be extremely distracting while watching a movie. Love that mid bass punch in the chest!
shadyJ posts on May 27, 2020 14:03
BRAC, post: 1393684, member: 91832
Need some help…I’m torn between a dual drive of these guys or 2x ML Dynamo 1600x. Both received great reviews here on the site. Which is the better performer for home theater?

Btw, I’m in Canada and can get the ML’s locally. The HSU’s would have to be imported. Cost works out roughly the same. Thanks!
Both are terrific subs. I think the Hsu subs are a bit more capable in deep bass and the Dynamo subs are a bit more capable in mid-bass. The Dynamo subs have a more sophisticated feature set and amplifier but the Hsu sub has a bit more robust driver. I would say that if you are connecting the sub to a system that doesn't have much in the way of bass management, go for the Dynamo since it has far more ways to control the performance. If you are hooking the sub up to a processor that does have a lot of bass management features, the Hsu sub may make more sense since it offers a bit more raw performance overall. But the Dynamo sub isn't that far from the ULS-15's performance.
BRAC posts on May 27, 2020 12:59
Need some help…I’m torn between a dual drive of these guys or 2x ML Dynamo 1600x. Both received great reviews here on the site. Which is the better performer for home theater?

Btw, I’m in Canada and can get the ML’s locally. The HSU’s would have to be imported. Cost works out roughly the same. Thanks!
ematthews posts on March 25, 2020 21:01
Matthew J Poes, post: 1377438, member: 85392
I know this is just feeding trolls here, but most don't understand, there is no such thing as made domestically. Nothing in our CE world can be made 100% domestically.

Only a very tiny fraction of amplifiers are made in America using american made modules. The amplifier circuits inside are still usually built in China and shipped as assembled modules. Those that aren't use “beans” made in China. It's impossible to do anything else. Those that are made mostly domestically (where only the beans are sourced from China) cost 1000's of dollars. Nothing most can afford.

I can't name names, I will probably get myself in trouble, but MANY companies that claim american made are not. I don't consider having all the guys fully assembled in China and shipped to the USA so they can be stuck inside a Chinese made box american made.

Those who think this kind of manufacturing is coming back to the US are nuts. It was never in the US. We've never been able to make those kinds of electronics in the US, by the time we shipped all that kind of production to China (70's) we gave up the ability, failed to progress, and left all the manufacturing development and infrastructure to China. We don't have the ability to create those kinds of facilities here and lack the workforce to man them. When I've asked about it (cost not withstanding) I've been told it would take a generation to even build a modicum of what China has. If a Foxconn built a facility to manufacture receivers, tablets, laptops, etc. in the USA and was totally vertically integrated, they would have to man it about 80% with Chinese workers. They would then need to work with the US education system to fundamentally change tech education to prepare folks to be able to work on the assembly lines, operate the machines, etc. It isn't that Americans are uneducated or stupid, quite the opposite. It's better described as wrongly educated. What we prepare people for isn't that kind of work. It's all relatively low paying, and would be here too. Whose going to get a tech degree to make $15 an hour.

That isn't america hating, that is just a fact of life. Reagan opened the door to trade with China and in that deal we shifted the manufacturing of consumer electronics from the USA to China. They ran with it and today have built the entire giant country into a huge powerhouse of CE production and logistics.

Best explanation I have read on this subject. Thanks for the good reply.
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