Hsu Research ULS-15 mk2 Subwoofer Review

[John Daddabbo]

I would prefer to use the term 'accuracy' rather than musical. 'Musical' can mean anything depending on who you ask. Accuracy is how faithful the subwoofer stays to the source material, which would be what I consider musical since I would rather the system not add or subtract anything to the recording. We don't want our speakers to add overtones to instruments or to miss fundamentals.

While I have heard the e112 and SB-13 Ultra, I don't have the extensive listening experience with them that I do with the ULS-15 mk2. However, extensive measurement sets exist for all three units (e112 reviewed here and SB-13 reviewed here). In terms of linear distortion, they can all achieve a flat frequency response and have good characteristics in the time domain. In terms of non-linear distortion, they all have very low harmonic distortion and noise products. However, the ULS-15 has a slightly wider dynamic range than the e112 or SB13. The e112 and SB13 have a nicer finish and more features, but with respect to performance they are not really more accurate. The premium that you pay for the e112 or SB13 isn't really going toward a higher quality sound, it is going toward a higher-grade finish and more bells and whistles.

That's exactly what I believe I have been hearing about the three of them, and since I do not need the higher-grade finish or any of the bells and whistles, I have been leaning towards multiple HSU ULS-15 MK2's. The only other option I feel worth investigating is that of the SVS PB16-ULTRA, however I very much fear going back to a Ported Subwoofer, even one as good as the SVS PB16-ULTRA. Throwing the SVS PB16-ULTRA into the mix, how do you feel it fairs compared to the other 3 Sealed subwoofers in terms of Musicality / Accuracy (for of course it plays much lower, as well as much louder in the lower octaves) ?

 

[KEW]

As an owner of dual JL audio e112 subwoofers, I would add that I believe much of the expense of these Subs is to pull off what they do with a 12 inch driver and comparatively compact dimensions as compared with the sb13 ultra and the Hsu uls-15.
They are at odds with physics and an expensive solution unless WAF is a concern in my humble opinion.

 

[John Daddabbo]

As an owner of dual JL audio e112 subwoofers, I would add that I believe much of the expense of these Subs is to pull off what they do with a 12 inch driver and comparatively compact dimensions as compared with the sb13 ultra and the Hsu uls-15.
They are at odds with physics and an expensive solution unless WAF is a concern in my humble opinion.

It isn't, I am free to go as large as I desire, which is why I recently added the Rythmik F25 to my short list, however I know so very little of Rythmik and there 'Servo' technology. So either quad HSU ULS-15 MK2 or dual Rythmik F25, assuming of course I am not seriously losing out by not 'upgrading' to either the SVS or JL, which I seem to be hearing that I would not at all be losing out in terms of Musicality / Accuracy. Along with my reluctance of going with the 'ported' SVS PB16-ULTRA, despite dual PB16-ULTRA's being clearly ideal in all 'other' aspects of a Subwoofer. Ps. I am trying to add the foundation to a pair of GoldenEar Triton Reference crossed-over at 40 hz, as well all other speakers of the 9.2.4 Dolby Atmos setup crossed-over at 60 hz, and 80 hz for the 4 Ceiling speakers. With my primary goal being Music over Home Theater, very much so.... hence that reluctance to go with dual PB16-ULTRA's.

 

[speakerman39]

It isn't, I am free to go as large as I desire, which is why I recently added the Rythmik F25 to my short list, however I know so very little of Rythmik and there 'Servo' technology. So either quad HSU ULS-15 MK2 or dual Rythmik F25, assuming of course I am not seriously losing out by not 'upgrading' to either the SVS or JL, which I seem to be hearing that I would not at all be losing out in terms of Musicality / Accuracy. With my reluctance of going with the 'ported' SVS PB16-ULTRA, despite dual PB16-ULTRA's being clearly ideal in all 'other' aspects of a Subwoofer.

John, I have owned the ULS 15 MK2 and it was very tight and punchy. Music was very well articulated as I am extremely picky when it comes to bass. The reason being, my preference is on music as HT is not really much of a concern to me. However, the ULS 15 MK2 did very well in my small room as far as HT is concerned.

Mine was a B-stock that I got for ONLY $762 shipped! Hence, duals would be $1524 shipped and would save you $125 for A-stocks. If you are interested in B-stocks, then give Kevin a call @Hsu and he will work with you. Best wishes in your decision.


Cheers,

Phil

BTW, the finish on the ULS 15 MK2 is actually kind of nice. It looked much better in person than on the website.

 

[shadyJ]

That's exactly what I believe I have been hearing about the three of them, and since I do not need the higher-grade finish or any of the bells and whistles, I have been leaning towards multiple HSU ULS-15 MK2's. The only other option I feel worth investigating is that of the SVS PB16-ULTRA, however I very much fear going back to a Ported Subwoofer, even one as good as the SVS PB16-ULTRA. Throwing the SVS PB16-ULTRA into the mix, how do you feel it fairs compared to the other 3 Sealed subwoofers in terms of Musicality / Accuracy (for of course it plays much lower, as well as much louder in the lower octaves) ?

I also have a lot of experience with the PB16-Ultra. Here is a review with extensive measurements. It is a very good sub, but its performance wheelhouse is more in the 16 Hz to 40 Hz range. That is mostly beneath the frequency bands of regular music. Above that range it is not bad, but isn't that much better than the ULS-15 or SB-13. Another potential issue with it is that it is very heavy- 176 lbs. You need at least two adults to carry it, and they have to be in good shape, seriously. What makes it worse is that its finish is a pristine gloss black, so you want to carry it in such a way that does not scuff that fine finish, and this is not an easy task, since it is quite large. By contrast the ULS-15 is only 65 lbs or so and is easy to move around by one person.

The PB16-Ultra will unquestionably give you superior performance for movies. It digs very deep and does so very cleanly. It has excellent non-linear distortion metrics, a tad better than the ULS-15 in the musical range of 40 Hz and above (although they are both so low in distortion that neither would really be audible). I would say that if you have the room for it, and money is not an object, and you will have a lot of help getting it into place, and you won't be moving it around after getting it into place, sure, go for the PB16-Ultra. However, for the same price as the PB16-ultra you could get three ULS-15s and that would be far superior in the music range of 40 Hz and above. You also do not need to be a power lifter to get them in place.

 

[shadyJ]

As an owner of dual JL audio e112 subwoofers, I would add that I believe much of the expense of these Subs is to pull off what they do with a 12 inch driver and comparatively compact dimensions as compared with the sb13 ultra and the Hsu uls-15.
They are at odds with physics and an expensive solution unless WAF is a concern in my humble opinion.

The problem with a sub like the e112 is that in order to make a small driver play well in deep bass, they have to make the moving assembly heavy. But making it heavy diminishes its high-frequency performance. They can kind of compensate for that by giving it a beastly amp, but then they have to give the driver a big voice coil which further adds to the weight and also greatly increases inductance. It's more of a vicious circle than a delicate balancing act when you want deep bass from a small diameter driver in a small enclosure. And it's not even that much smaller than the SB13 or ULS-15.

 

[John Daddabbo]

I also have a lot of experience with the PB16-Ultra. Here is a review with extensive measurements. It is a very good sub, but its performance wheelhouse is more in the 16 Hz to 40 Hz range. That is mostly beneath the frequency bands of regular music. Above that range it is not bad, but isn't that much better than the ULS-15 or SB-13. Another potential issue with it is that it is very heavy- 176 lbs. You need at least two adults to carry it, and they have to be in good shape, seriously. What makes it worse is that its finish is a pristine gloss black, so you want to carry it in such a way that does not scuff that fine finish, and this is not an easy task, since it is quite large. By contrast the ULS-15 is only 65 lbs or so and is easy to move around by one person.

The PB16-Ultra will unquestionably give you superior performance for movies. It digs very deep and does so very cleanly. It has excellent non-linear distortion metrics, a tad better than the ULS-15 in the musical range of 40 Hz and above (although they are both so low in distortion that neither would really be audible). I would say that if you have the room for it, and money is not an object, and you will have a lot of help getting it into place, and you won't be moving it around after getting it into place, sure, go for the PB16-Ultra. However, for the same price as the PB16-ultra you could get three ULS-15s and that would be far superior in the music range of 40 Hz and above. You also do not need to be a power lifter to get them in place.

Hmmm, I do agree with much (if not all) that you say, however are you suggesting that the SVS PB16-ULTRA is so Musical and Accurate as to even satisfy folks who put Music first, as well as have switched to only using sealed subwoofers? Is it possible that the SVS PB16-ULTRA is that good? For if the SVS PB16-ULTRA is in fact that good, then Yes going with dual PB16-ULTRAs seems to be the best choice (if as you state, one can both afford them, as well as deal with moving them about).

 

[shadyJ]

It isn't, I am free to go as large as I desire, which is why I recently added the Rythmik F25 to my short list, however I know so very little of Rythmik and there 'Servo' technology. So either quad HSU ULS-15 MK2 or dual Rythmik F25, assuming of course I am not seriously losing out by not 'upgrading' to either the SVS or JL, which I seem to be hearing that I would not at all be losing out in terms of Musicality / Accuracy. Along with my reluctance of going with the 'ported' SVS PB16-ULTRA, despite dual PB16-ULTRA's being clearly ideal in all 'other' aspects of a Subwoofer. Ps. I am trying to add the foundation to a pair of GoldenEar Triton Reference crossed-over at 40 hz, as well all other speakers of the 9.2.4 Dolby Atmos setup crossed-over at 60 hz, and 80 hz for the 4 Ceiling speakers. With my primary goal being Music over Home Theater, very much so.... hence that reluctance to go with dual PB16-ULTRA's.

If your budget permits, I would skip the F25 and just get separate 15" enclosure subs from Rythmik, like a bunch of F15HPs. The reason is the same as with the PB16-Ultra, the F25 is extremely heavy (170 lbs), and you would need a dolly just to get it anywhere. Much better to just get the 15"s in separate enclosures like E15HPs or F15HPs or ULS-15 mks. A LOT easier to move around and setup. One thing I have discovered about subs is that they can be a lot more fun when you can move them around easily and experiment with placement. Of course, that will not be an issue for you if you already have designated places for them and aren't able to put them anywhere else.

One thing I will add is that you might not want to stick with your intended crossover points. Let the measurements dictate crossover points, not the manufacture specs. Calibrate the system to whatever sounds and measures best once you get everything in place.

 

[shadyJ]

Hmmm, I do agree with much (if not all) that you say, however are you suggesting that the SVS PB16-ULTRA is so Musical and Accurate as to even satisfy folks who put Music first, as well as have switched to only using sealed subwoofers? Is it possible that the SVS PB16-ULTRA is that good? For if the SVS PB16-ULTRA is in fact that good, then Yes going with dual PB16-ULTRAs seems to be the best choice (if as you state, one can both afford them, as well as deal with moving them about).

The PB16 is pretty good, but what I would say is if you like your music loud, maybe get something else. They can get loud in music frequency ranges, but they will not compare to a stack of ULS-15s in that range. If you don't listen loud, the ULS-15s don't really have an advantage. As for as accuracy, one-on-one vs a ULS-15, they can get about as loud but had just a bit less harmonic distortion, however both subs are very clean and the audibility of distortion is very unlikely in either one, so I wouldn't worry about that too much. However, two ULS-15s vs one PB16 very much favors the ULS subs in music ranges regarding distortion, extremely low distortion quantities per decibel.

If you decide on the PB16s, you will need to plan out the logistics of getting them into place. That is a more serious matter than most people realize.

One more thing, don't put too much stock into the idea that sealed necessarily has finer sound quality than ported. Sealed designs have their own sound quality compromises.

 

[John Daddabbo]

If your budget permits, I would skip the F25 and just get separate 15" enclosure subs from Rythmik, like a bunch of F15HPs. The reason is the same as with the PB16-Ultra, the F25 is extremely heavy (170 lbs), and you would need a dolly just to get it anywhere. Much better to just get the 15"s in separate enclosures like E15HPs or F15HPs or ULS-15 mks. A LOT easier to move around and setup. One thing I have discovered about subs is that they can be a lot more fun when you can move them around easily and experiment with placement. Of course, that will not be an issue for you if you already have designated places for them and aren't able to put them anywhere else.

One thing I will add is that you might not want to stick with your intended crossover points. Let the measurements dictate crossover points, not the manufacture specs. Calibrate the system to whatever sounds and measures best once you get everything in place.

Before my very light and easy to move around 120 lbs each GoldenEar Triton Reference speakers, I owned 185 lbs each Legacy Audio Focus speakers, so I am used to dealing with weight and have no problems doing so... and therefore size and weight simply do not factor in for me, but Thank you.

 

[shadyJ]

Before my very light and easy to move around 120 lbs each GoldenEar Triton Reference speakers, I owned 185 lbs each Legacy Audio Focus speakers, so I am used to dealing with weight and have no problems doing so... and therefore size and weight simply do not factor in for me, but Thank you.

If size and weight are not a hindrance for you, that is enviable! However, if sound quality is your paramount concern, another reason to go with the Rythmik single 15" subwoofer cabinets is that the HP versions are using a better driver and more powerful amp then the F25 subwoofer. The F25 is using the lower end DS1501 drivers while the F15HP is using the DS1520 drivers I believe. You will have to talk to Rythmik about the specific driver versions, but I don't think the F25 would perform as well as a stack of ULS-15 mk2s or Rythmik F15HPs.

However, again, this would all only make a difference if you intended to listen loudly. If you aren't going to push this stuff hard, they will all operate extremely cleanly and won't sound very different after you calibrate their response curve.

 

[John Daddabbo]

The PB16 is pretty good, but what I would say is if you like your music loud, maybe get something else. They can get loud in music frequency ranges, but they will not compare to a stack of ULS-15s in that range. If you don't listen loud, the ULS-15s don't really have an advantage. As for as accuracy, one-on-one vs a ULS-15, they can get about as loud but had just a bit less harmonic distortion, however both subs are very clean and the audibility of distortion is very unlikely in either one, so I wouldn't worry about that too much. However, two ULS-15s vs one PB16 very much favors the ULS subs in music ranges regarding distortion, extremely low distortion quantities per decibel.

If you decide on the PB16s, you will need to plan out the logistics of getting them into place. That is a more serious matter than most people realize.

One more thing, don't put too much stock into the idea that sealed necessarily has finer sound quality than ported. Sealed designs have their own sound quality compromises.

Hmmm, interesting... and as I mentioned above I will crossing-over my GoldenEar Triton Reference to whatever Subwoofer at 40 hz, just as I have my Legacy Audio Focus before them (room placement and all taken into account). So it is only for Movies that any dual Subwoofer setup I decide on will be playing up to 60 hz due to my GoldenEar Triton Five (Wide, Side & Rear Surrounds) and up to 80 hz due to the smallish GoldenEar Invisa HTR-7000 ceiling speakers. So IF in fact the 'ported' SVS PB16-ULTRAs are really that good, and therefore will do justice to Music below 50, 40, 30, and even 20 hz (since the Music that I listen to does quite often dip below 50 hz), then it sounds like I need to seek out an audition of these 'ported' SVS PB16-ULTRAs for they 'may' just serve my Music quite well, and for sure they will serve up my Movies in spades! Ps. The GoldenEar Triton Reference's crossed-over at 40 hz can easily produce > 115 dB cleanly from 20 kHz down to the 40 hz crossover and powered by my Emotiva XPA-1 GEN2 600 watts into 8 Ohm amplifiers. Anyone who likes there Music LOUD, as I do, will Love the GoldenEar Triton Reference (even with only half the rated power of my Emotiva XPA-1 GEN2s).

 

[Foxrox]

I’m sure PB-16’s are truly amazing, and i would never dis SVS, but I think there may be better value for your application. If I had your setup and the money to buy dual PB-16’s, I’d be looking at dual JTR Captivator S1’s. More bang for the buck without all the frills. Great for low crossovers if the rest of your speakers are near full range. I’ve got no experience to back this recommendation. Just going off the specs. Those S1’s look like fun.

http://www.jtrspeakers.com/captivator-s1.html

 

[shadyJ]

I’m sure PB-16’s are truly amazing, and i would never dis SVS, but I think there may be better value for your application. If I had your setup and the money to buy dual PB-16’s, I’d be looking at dual JTR Captivator S1’s. More bang for the buck without all the frills. Great for low crossovers if the rest of your speakers are near full range. I’ve got no experience to back this recommendation. Just going off the specs. Those S1’s look like fun.

http://www.jtrspeakers.com/captivator-s1.html

Above 40 Hz, the JTR S1s promise to be far more powerful than the PB16-Ultras, however the PB16-Ultras are definitely going to have greater performance from 16 to 30 Hz, so it all depends on what frequency range you want to put emphasis on. At 12 Hz and below I would expect the S1 to have more output. Interestingly, the ULS-15 mk2 looks like it would keep up pretty well with the captivators when you break performance down into $/dB, so for the same price as one of the captivators, you can get multiple Hsus and have essentially the same level of performance.

 

[Touchez au grisbi]

I am sorry for thread necromancy, but since this conversation is attached to a very thorough and data-rich review, and since I'm thinking about making the ULS-15 mk2 my first sub (only one of them to begin with), I'd like to ask about a demurral---from principle rather than direct experience with the sub---from user 'Kyhl' in a thread over at the Steve Hoffman forum.

I'd eliminate the HSU from the list because I do not see an adjustable phase control. It will be nearly impossible to integrate even if you can place it anywhere in the room. If placement is limited this will be impossible to integrate without good bass management software.

Another SHF user 'avanti1960', in his his subwoofer integration tutorial, is equally emphatic:

...Many [subwoofers] do not have the continuous phase adjustment. This one happens to be critical for smooth integration. I would not recommend a subwoofer without this feature.

I use an AVR with Audyssey MultEQXT32, but this might not always be the case; I intend to get a mic/REW and do the work, but how much of a disadvantage would this be for someone just feeling his way into the sub game? In place of continuous phase adjustment on the sub itself, how do you make these adjustments to the ULS-15 mk2? It looks like a great deal and a piece of gear that I could "grow into"; but if I end up ditching an AVR as amplication, I'm not sure I'd know how to address the phasing issue, and with the Hsu I wonder if I'd have one less tool than if I purchased a sub with that control. Sorry if it's a question that belongs elsewhere.

 

[everettT]

I am sorry for thread necromancy, but since this conversation is attached to a very thorough and data-rich review, and since I'm thinking about making the ULS-15 mk2 my first sub (only one of them to begin with), I'd like to ask about a demurral---from principle rather than direct experience with the sub---from user 'Kyhl' in a thread over at the Steve Hoffman forum.


Another SHF user 'avanti1960', in his his subwoofer integration tutorial, is equally emphatic:


I use an AVR with Audyssey MultEQXT32, but this might not always be the case; I intend to get a mic/REW and do the work, but how much of a disadvantage would this be for someone just feeling his way into the sub game? In place of continuous phase adjustment on the sub itself, how do you make these adjustments to the ULS-15 mk2? It looks like a great deal and a piece of gear that I could "grow into"; but if I end up ditching an AVR as amplication, I'm not sure I'd know how to address the phasing issue, and with the Hsu I wonder if I'd have one less tool than if I purchased a sub with that control. Sorry if it's a question that belongs elsewhere.

From Audyessey :
The phase controls on the back of the subwoofer are basically useless and should be left at 0. The reason for that is that the phase varies with frequency, but the control does not. So, when you set it at some value it is only adjusting the phase for one frequency and probably causing all kinds of artifacts at other frequencies. You could get lucky and have only one frequency with a problem that you catch with the phase control, but that would be pretty rare.

 

[shadyJ]

I am sorry for thread necromancy, but since this conversation is attached to a very thorough and data-rich review, and since I'm thinking about making the ULS-15 mk2 my first sub (only one of them to begin with), I'd like to ask about a demurral---from principle rather than direct experience with the sub---from user 'Kyhl' in a thread over at the Steve Hoffman forum.


Another SHF user 'avanti1960', in his his subwoofer integration tutorial, is equally emphatic:


I use an AVR with Audyssey MultEQXT32, but this might not always be the case; I intend to get a mic/REW and do the work, but how much of a disadvantage would this be for someone just feeling his way into the sub game? In place of continuous phase adjustment on the sub itself, how do you make these adjustments to the ULS-15 mk2? It looks like a great deal and a piece of gear that I could "grow into"; but if I end up ditching an AVR as amplication, I'm not sure I'd know how to address the phasing issue, and with the Hsu I wonder if I'd have one less tool than if I purchased a sub with that control. Sorry if it's a question that belongs elsewhere.

Continuous phase controls are only beneficial in certain situations, pretty much only when there is a lot of processing being done on the main speaker sound but none done on the sub. That would be a rare situation. If you don't use use Audyssey, you will want the sub set at zero degrees so it is in sync with the speakers if the speakers don't have a lot of processing. If you do use Audyssey, it doesn't matter what the phase is set to, since Audyssey will align the phase with the speakers regardless. Subwoofer placement will be a much greater variable toward integration than phase control limitations.

 

[Touchez au grisbi]

Thanks very much for the help, guys. I don't know if there are special challenges in placement of this particular sub (the Hsu), or for that matter just a sub of this size; but even if placement wisdom can be generalized, I'd appreciate a pointer to a reliable tutorial on integration. I mean, they are all over the place, but it sounds like I just shared a link to one with bad info. I am too new at this...I don't know the difference!

Hsu's own suggestions in the quick-guide/manual seem pretty casual and worry-free. Maybe I am making too much of it.

 

[everettT]

Thanks very much for the help, guys. I don't know if there are special challenges in placement of this particular sub (the Hsu), or for that matter just a sub of this size; but even if placement wisdom can be generalized, I'd appreciate a pointer to a reliable tutorial on integration. I mean, they are all over the place, but it sounds like I just shared a link to one with bad info. I am too new at this...I don't know the difference!

Hsu's own suggestions in the quick-guide/manual seem pretty casual and worry-free. Maybe I am making too much of it.

The sub crawl is an easy method. Place the sub in the main seat then go around the room vent over or crawl and see which part of the room sounds the best, then put the sub there. More intensive is REW measurements and simulations. You can start with mid wall placement as quick method.

 

[John Parks]

Touchez, it is entirely possible to get way too caught up in the whole process and believe you may be missing out or be lacking something if you do not “tune” to the nth degree. I have the ULS-15 MK2 in a simple, 2.1 setup with no equalization other than what is provided on the back panel of the sub and my ears and you know what? It sounds completely awesome! The ULS is a fantastic subwoofer and offers more performance than I could possibly use in my current configuration (yeah, it is a bit of overkill…). Due to it being sealed, it is extremely fast and there is no bass “bloat” whatsoever – I can only imagine how much better it would be with some sort of EQ program.

TL/DR – Go for it and have fun!