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Hsu Research ULS-15 mk2 Subwoofer Listening Sessions

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I adjusted the crossover frequencies between 80 Hz and 100 Hz depending on the material and what aspect of the sound was being evaluated. Most listening was done with the ULS-15 mk2 in the EQ1 mode with a Q setting of 0.7. Equipment used was a Pioneer Elite SC-55 and Infinity Primus speaker set. The subwoofer location in my listening room with the most even overall frequency response for the ULS-15 mk2 still produced a 10 dB dip centered around 40 Hz, and this must be kept in mind while reading any listening impressions for this review. Few rooms support a really good response with a single subwoofer, and for this reason Audioholics stresses the need for multiple subwoofers for a really good bass sound. The point here is that the character of the sound this sub has in my room at my listening position will not be the same as in any other room, and this will be true of any single subwoofer installation in any subwoofer review.

Music Listening11_cantstoprunning.jpg

After watching Adam Ben Ezra’s virtuoso double bass performances on Youtube (such as this terrific example), I decided to give his trio’s 2015 debut album, ‘Can’t Stop Running’ a spin. Although the bass doesn’t dig very deep, it is nonetheless an excellent jazz album with which to demo subwoofers because of Ezra’s nuanced playing. The bass is subtle, percussive, multi-layered and bold, but always masterfully performed. The various slides, slaps, and occasionally even polyphonic double bass play are like candy to a capable subwoofer. Kick drums also shine through on this album.

The Hsu ULS-15 mk2 reproduced ‘Can’t Stop Running’ with aplomb. It brought weight and power to the double bass without any sense of exaggeration. The ULS-15 mk2 effortlessly nailed the transient nature of the performance; the sharp pluck attacks of the double bass and the acute starts and stops from the slaps. The mk2 made it difficult not to bob one’s head along with Ezra’s rhythmic bass lines, and it was clear that both the recording and the ULS-15 mk2 deserved better main speakers for greater realism, but the experience was still a delight. 

For a completely different bass experience, I turned to an experimental album from a 1995 entitled ‘A Storm of Drones: The Sombient Trilogy’. This triple-CD release is keyed to gloomy, dissonant sounds in a kind of dark ambience. It is filled with many types of low frequency noises; drones of different textures and intensities, distant rumbling, low-frequency buzzing like a swarm of monstrous bees, electronic whooshes and hums, and foreboding sounds of all manner. It would make an appropriate soundtrack for a nightmare. Much of the bass is subtle, but occasionally it becomes dominant and striking, and a lesser subwoofer can easily make too much of what should only be a hint of low-frequency sound or miss it completely. Happily, the ULS-15 mk2 did neither and gave the low-frequency elements of ‘A Storm of Drones’ a presence without being inordinate. The ULS-15 mk2 rendered the finer details of dread with exquisite care, not overdoing it, and not going MIA either, which would make for a hollow sound. The balancing act in competently reproducing bass on many tracks on ‘A Storm of Drones’ can be seen in a spectrogram, where there is much simultaneous content across many low frequencies, but none of it is recorded at high energy levels. This can become either a muddy, indiscriminate rumble in the hands of an inferior subwoofer or a rich and textured undercurrent in the care of a high-fidelity subwoofer, and the ULS-15 mk2 is firmly in the latter camp.

12_storm_of_drones.jpg     13_anatomy.jpg

Enough with subtlety and delicacy, it was time to let the sub rip and a great choice for pummeling a subwoofer with brutal bass is Calyx and Teebee’s now classic 2007 Drum’n’Bass album ‘Anatomy’. High-tempo breakbeats, bruising yet melodic bass lines, cuts of orchestral recordings, and samples of portentous dialogue from various movies is the stuff that ‘Anatomy’ is made of. This is not a recording to which one sips a fine chardonnay while admiring the understated elegance of a Cezanne painting. It is more like the soundtrack for the final battle of the great cyborg vs. android war of the early 25th century. Most of this album’s energy is in the lowest frequencies and rare are the moments in ‘Anatomy’ when the dynamic range isn’t saturated, so it becomes a nearly continuous assault on bass drivers. The ULS-15 mk2 was as comfortable with this material as it was with the more delicate bass on other music recordings. The punch on kick drums was concussion-inducing, and the buzz from the bass lines could be felt in the chest. ‘Anatomy,’ as reproduced by the ULS-15 mk2, is a positively visceral experience at high volumes. ‘Hearing’ is almost too soft of a word for the experience, and a more apt description would be the ‘sensation of pressure,’ since these output levels seem to cause an involuntary muscle tension that doesn’t end until the end of the track. The subwoofer withstood this assault admirably with no noticeable complaints, even at very high excursion levels.

Movies      

The ULS-15 mk2 provided a positively visceral experience at high volumes.

One movie I watched with the ULS-15 mk2 was ‘Letters From Iwo Jima’, Clint Eastwood’s highly-regarded 2006 World War 2 drama. While there may be movies out there that have a greater quantity of low-frequency sound content, ‘Letters From Iwo Jima’ has a nice variety of low frequency material that gives the subwoofer plenty to do without overdoing the bass. Another reason why I selected ‘Letters From Iwo Jima’ is because there are so few truly adult dramas that allow the subwoofer to stretch its legs, and ‘Letters’ is one of them. There is much to keep the sub active in ‘Letters From Iwo Jima’, from aerial bombardment, heavy machine guns, ship-mounted artillery fire, mortars, tanks, grenades, and an altogether diverse spread of WW2 sound effects. The ULS-15 mk2 convincingly relayed the sharp thuds of bullet strikes, the rumble of distant explosions, and the subterranean pounding of outside bombardment within a cave network. Thunderous battle sequences were brought to life by the ULS-15 mk2, and I didn’t get the sense at all that these scenes were being hindered by the dynamic range of the subwoofer. I watched the film at a relatively loud level, but it seemed to me that the mk2 still had some muscle left had I wanted to push things harder. In the end, I thought that the precision and power of the ‘Letters’ soundtrack was well-matched by the ULS-15 mk2.

14_letters_iwo_jima.jpg     15_good_day_die_hard.jpg


Another film I viewed with the ULS-15 mk2 was the fifth movie in the Die Hard series, 2013’s ‘A Good Day to Die Hard’. Yeah, I know, it isn’t on the artistic level of the others, but it still contains some pretty good action scenes and a creditably dynamic soundtrack. The movie features a lengthy, tumultuous car chase, gun fights against military helicopters, dozens of explosions, and a brawny orchestral music score by Marco Beltrami, so the ULS was kept busy. The crashes, booms, and blasts were all vividly reproduced by the ULS-15 mk2, and this is no surprise after having spent some time with it. At loud volumes, the low frequency effects brought out some very high excursions from the driver in EQ1 mode, but there was no sign that the sub was being harmed. High-output in deep frequencies is a lot to ask for from a sealed sub, especially in a medium-large room. Switching the sub to EQ2 mode tamed the large excursions. This is not to say the sub can’t handle that kind of heavy use, it’s just something you don’t want to put your subwoofer through frequently.

 

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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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