• 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.

NHT SB2 Speaker Review

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
25,948
Likes
57,776
Location
Seattle Area
#1
This is a review and detailed measurements of the NHT SB2 bookshelf speaker. It is kindly sent to me by a member. I think the SB2 came out back in 2002 when NHT was a different company than it is now (it closed and re-opened as a direct to consumer company). At the time, the SB2 cost US $400 for a pair.

The fit and finish of the SB2 is quite nice:

NHT SB2 Bookshelf Speaker Audio Review.jpg


This is a super sturdy cabinet with no ports. It has a "piano black" coating which gives it a higher-end feel. The tweeter is a bit cheesy looking though and lacks a waveguide for good integration with the woofer.

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.

At the risk of creating grief for people using my spinorama measurements :), this is a higher resolution (in frequency domain) scan.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

NHT SB2 Bookshelf Speaker Spinorama CEA2034 Frequency Response Audio Measurements.png


Sadly we have a lot of flaws. Frequency response is anything but flat with share of both peaks and dips and elevated high end. Not a good idea to apply this EQ to everything you play.

Above is similar to a much more crude measurement by another site:https://www.soundandvision.com/content/war-little-worlds-first-place



Sensitivity is all over the place (depending on frequency) but is probably around 82 dB which is pretty low. Company says it is 86 dB.


The SB2 is the purple graph which shares the same ups and downs as my measurements. As an aside, they gave it the best score of the speakers they had rounded up for their testing.

Off-axis response is also odd-shaped:
NHT SB2 Bookshelf Speaker Spinorama CEA2034 Early Reflections Frequency Response Audio Measure...png


Leading to a predicted in-room response with an uneven response:

NHT SB2 Bookshelf Speaker Spinorama CEA2034 Predicted In-room Response Frequency Response Audi...png


Directivity plot shows how the woofer and tweeter don't meet each other with the same sound cone size at crossover frequencies:

NHT SB2 Bookshelf Speaker Horizontal Directivity Frequency Response Audio Measurements.png


The larger sin though is the uneven response.

Vertical response is bad but that is more often than not the case:
NHT SB2 Bookshelf Speaker Vertical Directivity Frequency Response Audio Measurements.png


NHT says the nominal impedance is 8 ohm but your amp better be able to drive 4 ohm load:

NHT SB2 Bookshelf Speaker Phase and Impedance Audio Measurements.png


Distortion when compensated for room effects is higher than I like to see in mid-frequencies where our hearing is very sensitive:

NHT SB2 Bookshelf Speaker THD distortion percentage Audio Measurements.png


Note that per suggestion from members, I ran these distortion tests at 86 dB instead of 96 dB that I use for larger speakers.

NHT SB2 Bookshelf Speaker THD distortion Audio Measurements.png


Interesting that distortion rises around the same peaking of 700 to 900 Hz. Is that the woofer breaking up? Or is tweeter playing down that low and doing it?

Some sign of the same is in the CSD/waterfall:

NHT SB2 Bookshelf Speaker CSD Waterfall Audio Measurements.png


Speaker Listening Tests
I immediately cringed when I played the first track on SB2. It was bright and just not right. I then dialed in a quick, single filter in Roon player to pull that peak around 800 to 900 Hz:

NHT SB2 Bookshelf Speaker Corrective Equalization.png


Wow, that was transformative! Detail immediately increased due likely to removal of the distortion/resonance causing that peak.

The sound was still bright but I did not want to keep messing with it. With just that one filter, the speaker went from bad to, "hey, this is not half bad!" I enjoyed my next few tracks until I stopped to post this review.

Note that the SB2 is extremely inefficient. I had to turn up the volume to levels on my 1000 watt amplifier that I rarely ever use with any speaker. Practical efficiency is probably less than 80 dB. Good news is that there was no break up. The bass was unclean at higher levels but it was livable.

Conclusions
NHT had quite a good reputation in its original incarnation when this speaker was release. It is sad to see it have such poor objective performance out of the box. Fortunately with a bit of EQ it becomes reasonable. Build quality and sturdiness of the cabinet is likely better than anything you can get for $400 today.

Overall, I can't recommend the NHT SB2. It clearly was not designed with best goals of produce a neutral and transparent sound.

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

Had to plant my corn transplants in the garden. With none of you volunteering to do the digging and fertilizing of the soil before planting them, I had to hire my helper again and am out another $100. And he has to come back tomorrow for planing tomatoes. Needless to say, I am feeling poor and hence, depressed. I hope you can cheer me up by donating as much as you can using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Attachments

Trouble Maker

Active Member
Joined
Jan 6, 2020
Messages
133
Likes
84
Location
Japan via Ohio
#3
I wonder if these are the same drivers as the ST4. I demoed, I think around 2001 and really liked them. My dad ended up buying and still has them.
If so, that shows what my ears know. :) I've tried to find measurements for the ST4 to no avail.
I also always really liked the finish on the ST4s, which I would assume is the same across the lineup.

EDIT: Maybe the same line, but looks like the same drivers as the SB3 (bigger than SB2).
"Inside the Super Tower are two separate chambers, one containing the same high-quality midrange and tweeter drivers as the NHT SB3..."
https://cdn.connectsites.net/user_files/nht/downloads/000/003/116/st4.pdf?1427144638
The differences, and also lack of between the SB2 and SB3 seem strange in the same lineup.
 
Last edited:

ferongr

Member
Forum Donor
Joined
Mar 27, 2019
Messages
43
Likes
98
#4
Note that per suggestion from members, I ran these distortion tests at 86 dB instead of 96 dB that I use for larger speakers.
I know that this subject has been done to death, but in my opinion, if a speaker cannot cope with 96dB at 1 meter it shouldn't be called a speaker but a headphone. The change in test protocol is a bit disappointing.
 

wwenze

Active Member
Joined
May 22, 2018
Messages
249
Likes
275
#8
I can see the internal conflict inside a reviewer's soul as this is typed.
Trying to be polite while remaining objective is always hard.

NHT had quite a good reputation in its original incarnation when this speaker was release. It is sad to see it have such poor objective performance out of the box. Fortunately with a bit of EQ it becomes reasonable. Build quality and sturdiness of the cabinet is likely better than anything you can get for $400 today.
 

Billy Budapest

Active Member
Forum Donor
Joined
Oct 11, 2019
Messages
193
Likes
165
#13
I’ve never heard anything good about the SB2. The SB3, on the other hand, has received lots of raves. It’s driver complement is inverted, with the tweeter below the mid-woofer.
 
Joined
Nov 22, 2018
Messages
416
Likes
219
#14
I'm curious of the SuperOne now...
 

Ron Texas

Major Contributor
Joined
Jun 10, 2018
Messages
2,731
Likes
2,784
Location
Under House Arrest
#15
At least we don't have to run out and worry about buying one of these. Is there any chance the unit degraded due to it's age?
 
Joined
Feb 23, 2019
Messages
12
Likes
3
#17
I am very curious about the SuperZero / SuperOne. The woofers on those models are still shielded to this day, which would mean that they may be usable in the retro gaming setup I'm putting together (near a CRT video monitor). It would be great if they measured well, I would definitely pounce for them in that case. Otherwise I'm stuck with something a lot cheaper or with putting my speakers in an awkward placement.
 

jhaider

Addicted to Fun and Learning
Joined
Jun 5, 2016
Messages
793
Likes
824
#18
Surprising. NHT at the time was as said quite highly thought of. (This was the Jack Hidley era?) I think their flagship of the era (the 4 way Evolution T6) was Stereophile’s least expensive “class a” speaker. As previously mentioned at least their current 3-way standmount is outstanding. The previous one was very good too.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
25,948
Likes
57,776
Location
Seattle Area
Thread Starter #19
At least we don't have to run out and worry about buying one of these. Is there any chance the unit degraded due to it's age?
Measurements are similar to one that was measured in that magazine new. So I think it is working as designed.
 
Top Bottom