• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

HSU HB-1 MK2 Review (Horn Speaker)

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
34,986
Likes
130,321
Location
Seattle Area
This is a review and detailed measurements of the HSU HB-1 MK 2 bookshelf speaker. It is on kind loan from a member and costs US $169 each as of this writing (normal price $199).

I can't say I am a fan of the industrial looking horn but otherwise, the HB-1 looks fine:

HB-1 MK2 Review Horn Bookshelf Speaker.jpg


As you see, it uses a horn-loaded tweeter. Not much to see on the back:

HB-1 MK2 Review back panel binding posts Horn Bookshelf Speaker.jpg


Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

I performed over 1000 measurement which resulted in error rate of less than 1%. Temperature was 78 degrees F.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

Reference axis was the tweeter center. The front baffler is slanted back. I measured it however as if it were not.

HSU HB-1 MK2 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

HB-1 MK2 Frequency Response Measurements Horn Bookshelf Speaker.png


At first glance the on-axis response looks pretty messy but it is mostly so above 4 kHz. Below that, it is more or less flat within context of a budget speaker. We can see the responsible actors for the frequency response in our near-field measurements of each radiating surface:

HSU HB-1 MK2 near-field driver  Frequency Response Measurements Horn Bookshelf Speaker.png


The cabinet resonance radiating through the port is kept at a lower frequency so that it doesn't interfere with the crossover region as much as it does on many other speakers. Woofer could use a sharp filter to not let it resonate in the 2 to 4 kHz. And tweeter/horn could be more well behaved above 10 kHz.

Directivity has some kinks here and there but overall, it is good enough that the off-axis response is similar to on-axis:

HSU HB-1 MK2 Early Window Frequency Response Measurements Horn Bookshelf Speaker.png


Thankfully the tweeter response narrows in the upper registers which reduces the on-axis resonance we saw at > 10 kHz. So combined the predicted response looks better than our original spin graph shows:

HSU HB-1 MK2 Predicted in-room Frequency Response Measurements Horn Bookshelf Speaker.png


What do you think this sounds like? Too bright? What about that dip around 4 kHz? Listening tests will answer.

Distortion at 86 dBSPL is kept in check but naturally gets much worse at 96:

HSU HB-1 MK2 Distortion Percentage Measurements Horn Bookshelf Speaker.png


HSU HB-1 MK2 Distortion THD Percentage Measurements Horn Bookshelf Speaker.png


I mentioned earlier that the tweeter beam width narrows in higher frequencies which we clearly see that in our beam width graph:
HSU HB-1 MK2 Horizontal Beam width  Measurements Horn Bookshelf Speaker.png


So best to point the speaker at you like the manual suggests.

HSU HB-1 MK2 Horizontal directivity Measurements Horn Bookshelf Speaker.png


At the extreme of the frequency range though, we see a widening which I wonder if it is caused by diffraction at various corners of the horn.

Here is the vertical directivity:

HSU HB-1 MK2 Vertical directivity Measurements Horn Bookshelf Speaker.png


There is an "eye" (hole) in response around 2.5 kHz so best to sit at or (slightly) above tweeter axis.

Finally, here is our impedance and phase graphs:

HSU HB-1 MK2 Impedance and phase vs Frequency Measurements Horn Bookshelf Speaker.png


HSU HB-1 MK2 Listening Tests
Anyone who thinks you don't need to listen to speakers in objective reviews, should listen to the HSU. Despite the large variations in on-axis response, the overall tonality is almost correct. There is hardly anything to complain about. I took out the EQ tool to see if fixing the response errors make the experience better:

HSU HB-1 MK2 Equalization EQ Paramtric  Horn Bookshelf Speaker.png


It took fair bit of doing to create a subjective experience that was better than stock tuning. Filling the hole around 3.5 to 4 kHz took some effort to make sure the overall tonal character wasn't too bright. The upper filters have very subtle effects due to our hearing dropping off rapidly as we get older. Still, I thought the sound was a bit more open and highs a bit more controlled with EQ.

Once there, or even without EQ, this is a very listenable speaker. It handles tons of power. It essentially doesn't bottom out on deep bass. Instead, it makes some noises and has tonal shifts which I prefer to sudden onset of the driver running out of excursion. That horn loading must enable the tweeter to better keep up with the woofer as once again, I am experiencing something slightly unique here in dynamic capability with a horn tweeter as opposed to normal waveguide.

Despite using a single speaker, I could fill my entire large space with sound but it took tons of power. I think the company advertises sensitivity of 92 dB which is a fantasy likely measured like Klipsch at the peak of tweeter resonance. I used almost every bit of my 1000 watt amplifier to drive it at highest playback level.

As an interesting aside, I could see creases in the woofer surround as I pushed it with deep bass but the audible results was not nearly as bad as the visual inspection would predict.

Conclusions
At first glance, the objective measurements of the HSU HB-1 MK 2 indicates a number of problems but a more learned look shows near flat response up to 3+ kHz where most of the spectrum of music is. So no wonder that the subjective experience was mostly positive. It seems that weaknesses of the designs are in areas where it audibly matters less and strength such as very high SPL playback ability are presented front and center. I can't say that we have enough research to objectively quantify everything that is going on in this package. Some interesting compromises were made here to produce a package that performs better than it should "on paper."

My preference is for speakers that objectively leave no question about their performance. But I have to make an exception here and go with my overall experience and a more specific analysis of the objective measurements to put the HSU HB-1 MK 2 on my recommended list.

------------
As always, questions, comments, recommendations, etc. are welcome.

Man, it has been hell around the house. The wife smelled a bit of sewage in our drain field. Long story short, roots had grown into the distribution box and I spent the entire day with my head inside the stupid box cutting them out and cleaning up the thing. It was one of the hottest days of the week of course causing me to sweat like nobody's business. On top of that, I tested a couple of products that were defective so couldn't publish their reviews. Hence the slow pace of reviews.

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Attachments

  • HSU HB-1 MK 2.zip
    88.7 KB · Views: 34

MZKM

Major Contributor
Forum Donor
Joined
Dec 1, 2018
Messages
3,801
Likes
9,431
Location
Land O’ Lakes, FL
I wonder if measuring it as-is (not accounting for baffle slope) would have been better.

They used to offer a wood finish for an uncharge, but I no longer see that option.
s_hsu.jpg


Also, they spec it 92dB in half space. Not sure if that means +6dB or +3dB. The measured sensitivity using my parameters is almost 87dB.

They also spec it 60Hz-20kHz +/-2dB, very bold of them but turns out to be false advertising.

They also spec it as 8ohm but with a 4.1ohm minimum the IEC spec would call that 6ohm.

Note the $169 is without $30 shipping, so $398/pair shipped plus applicable tax (they are based in California).

As for MKI vs MK II, they state this:
"The second generation (MK2) HB-1 boasts flatter frequency response, improved horn, and more powerful Neodymium magnet for the tweeter, and greatly improved looks"

Some measurements of the first gen can be found here:
https://hometheaterreview.com/hsu-research-hb-1-mk2-bookshelf-loudspeaker-reviewed/
 
Last edited:

q3cpma

Major Contributor
Joined
May 22, 2019
Messages
2,981
Likes
4,004
Location
France
Interesting for the price, but still flawed in many ways. Never seen such a horn shape before, but it doesn't seem to have constant directivity as a goal.
 

Billy Budapest

Addicted to Fun and Learning
Forum Donor
Joined
Oct 11, 2019
Messages
845
Likes
1,000
Hsu Research takes pride in being an engineering-based company so I am surprised the measurements aren’t better than what the Klippel revealed. Still, I am not surprised they sound good given the large and loyal following they have.
 

MZKM

Major Contributor
Forum Donor
Joined
Dec 1, 2018
Messages
3,801
Likes
9,431
Location
Land O’ Lakes, FL
Never seen such a horn shape before, but it doesn't seem to have constant directivity as a goal.
HSU & BIC America share an unknown relationship with Dr. Hsu contracted for design on some models. BIC’s contact page is the same building as HSU, but BIC’s address on their footer states another city…

The BIC FH-65B has the same horn design and is ~$110/each on Amazon ($105 at Home Depot & Lowe’s):
https://www.amazon.com/BIC-America-Formula-FH-65B-175/dp/B004157XZA
5000052367.jpg

BIC also has towers of this model (HSU has no tower speakers, odd).
 
Last edited:

ClosDeLaRoche

Active Member
Joined
Jun 21, 2019
Messages
107
Likes
87
I bought a pair of these for $300 on craigslist once. I loved them for the price. I bought a Klipsch 600M as an upgrade but returned the Klipsch as I liked these more for less money. I think that's where the HB-1 MK2 shines: a better option for those on a budget and considering the 600M.

Eventually I settled on the LS50 which is a step up from both the HB-1 MK2 and 600M. I did pair the LS50 with HSU's ULS-15 MK2 sub :)
 

DWPress

Senior Member
Forum Donor
Joined
May 30, 2018
Messages
349
Likes
412
Location
MI
Long story short, roots had grown into the distribution box and I spent the entire day with my head inside the stupid box cutting them out and cleaning up the thing.

Must be going around - the line from my secondary liquid tank to septic field (river waterfront so pumped 100 yards up the driveway with a 10' lift) has been fouled by roots. I've spent way too much time on the stupid end of a shovel and head in gastly places. Good luck Amir!
 

Helicopter

Major Contributor
Forum Donor
Joined
Aug 13, 2020
Messages
2,462
Likes
3,370
Location
Michigan
Thanks Amir.

This is much better than I expected. I had considered these, figured RP-600M was better, and determined RP-600M was not good enough. Too bad they don't have famous horn efficiency. I am sure the tweeter is padded down for that aluminum cone.

Sorry to hear about the roots, hot weather, and defective units. At least you put things in perspective for me. ;) I will count my blessings trying to work and care for a sick toddler here. I hope things turn around for the better soon.
 

abdo123

Major Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
3,685
Likes
3,201
Location
Brussels, Belgium
@amirm

Do you think this Speaker would be an outlier if it were to be included in Olive's Preference studies? It doesn't look super pretty.
 

Robbo99999

Major Contributor
Forum Donor
Joined
Jan 23, 2020
Messages
2,925
Likes
2,451
Location
UK
What I'm surprised about re this little speaker is what Amir said here:
Despite using a single speaker, I could fill my entire large space with sound but it took tons of power. I think the company advertises sensitivity of 92 dB which is a fantasy likely measured like Klipsch at the peak of tweeter resonance. I used almost every bit of my 1000 watt amplifier to drive it at highest playback level.

I find it so surprising that something so small required so much power to drive. Isn't this an issue with the design.....I mean who would buy a tiny speaker like this (which is not a bass monster nor an absolute SPL ear splitter) and expect to have to drive it with one of the most powerful amps on the planet.....isn't this a practical problem for usage of this speaker? (I'm not really familiar with passive speakers, so maybe I'm missing something.) Also this speaker is not an expensive speaker, so there's a bit of a mismatch if it requires an uber expensive powerful amp to drive them effectively.
 

abdo123

Major Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
3,685
Likes
3,201
Location
Brussels, Belgium
What I'm surprised about re this little speaker is what Amir said here:
Despite using a single speaker, I could fill my entire large space with sound but it took tons of power. I think the company advertises sensitivity of 92 dB which is a fantasy likely measured like Klipsch at the peak of tweeter resonance. I used almost every bit of my 1000 watt amplifier to drive it at highest playback level.

I find it so surprising that something so small required so much power to drive. Isn't this an issue with the design.....I mean who would buy a tiny speaker like this (which is not a bass monster nor an absolute SPL ear splitter) and expect to have to drive it with one of the most powerful amps on the planet.....isn't this a practical problem for usage of this speaker? (I'm not really familiar with passive speakers, so maybe I'm missing something.) Also this speaker is not an expensive speaker, so there's a bit of a mismatch if it requires an uber expensive powerful amp to drive them effectively.

Actually the trend has been that the smaller the speaker the less sensitive it is.

‘Big speakers’ have been mostly advertised as home cinema speakers and for that purpose they need to get loud, and without difficulty.
 

Robbo99999

Major Contributor
Forum Donor
Joined
Jan 23, 2020
Messages
2,925
Likes
2,451
Location
UK
Actually the trend has been that the smaller the speaker the less sensitive it is.

‘Big speakers’ have been mostly advertised as home cinema speakers and for that purpose they need to get loud, and without difficulty.
Ah, ok. But why would you want to buy a $200 speaker and have to match it with a $10,000 uber powerful amplifier? (Amir's costs something like that right). I mean 1000W of amplifier power isn't going to be cheap is it, ever? How does that marry to pairing it with a $200 speaker?
 

abdo123

Major Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
3,685
Likes
3,201
Location
Brussels, Belgium
Ah, ok. But why would you want to buy a $200 speaker and have to match it with a $10,000 uber powerful amplifier? (Amir's costs something like that right). I mean 1000W of amplifier power isn't going to be cheap is it, ever? How does that marry to pairing it with a $200 speaker?

I don’t get where this 1000W is coming from, sensitivity is 86.8 dB and that’s fairly common.

Perhaps there is severe compression?
 

MZKM

Major Contributor
Forum Donor
Joined
Dec 1, 2018
Messages
3,801
Likes
9,431
Location
Land O’ Lakes, FL
I don’t get where this 1000W is coming from, sensitivity is 86.8 dB and that’s fairly common.

Perhaps there is severe compression?
Amir stated he used his 1000W amp near to the max with these. However, that was to obtain the high playback levels. But many bookshelves cannot get to this high playback level in his space. So, I think it's just telling of good power handling.

Amir stated the Emotiva B1+ could get "very loud" and that is 1dB less sensitive than this HSU. Would be interesting to know which has higher max SPL.
 

maverickronin

Major Contributor
Forum Donor
Joined
Jul 19, 2018
Messages
1,947
Likes
2,306
Location
Midwest, USA
Ah, ok. But why would you want to buy a $200 speaker and have to match it with a $10,000 uber powerful amplifier? (Amir's costs something like that right). I mean 1000W of amplifier power isn't going to be cheap is it, ever? How does that marry to pairing it with a $200 speaker?

Who says you have to go with ML's TOTL model for a 1kW amp? There's always Crown or Behringer.
 
Top Bottom