This is a review and detailed measurements of the NHT Super Zero 2.1 "Mini Monitor" speaker review. Despite the "monitor" designation, this is a passive speaker needing external amplification. I purchased this unit back in January for US $70 (single unit). Company list price is US $149 but is on sale now for $125 (again, each).
This is a very compact and rather dense speaker:
The back panel shows lack of any kind of port:
The finish is nice and glossy but the corners are very sharp which is not easy on the hand or measurements likely.
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 800 measurement which resulted in error rate of less than 1% throughout the range.
Temperature was 60 degrees F. Measurement location is at sea level so you compute the pressure.
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.
NHT Super Zero 2.1 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:
The most glaring issue he is lack of bass response which is due to lack of port and tiny enclosure. Second issue related to same factors is very low sensitivity. Third is poor directivity due to lack of any mechanism to get the beamwidth of the tweeter and woofer to match at crossover point:
The blue arrow shows the classic response of a tweeter (or any driver) as wavelengths get smaller. The tweeter gets progressively more directional. Same is happening to the woofer so we get a mismatch around 4 to 5 kHz. This then translates into our off-axis response being uneven and not match the direct sound:
Result is a response with a dip in critical range of music:
Combine that with lack of bass and this speaker will likely not sound good.
Directivity plots show what we have seen already:
Distortion story naturally is not good:
Finally here is our impedance and phase:
EDIT: forgot the drive response:
NHT Super Zero 2.1 Speaker Listening Tests
I hooked up the 2.1 to my main system placed on top of a stand for standard far-field listening. The sound was dead on multiple fronts: there was no volume making me crank my powerful amplifier to ungodly levels. Then there was no bass and I mean no bass. The moment the music would rely on bass notes to carry on, the sound level would go way down. Ditto for anything in 2 to 3 kHz range. A 3 dB boost in that region gave the speaker some lift but really, I was so unhappy with the experience that I shut everything off and that was all she told.
Conclusions
Amazing that a company like NHT that had a great reputation in the 1990s into 2000s has fallen by the wayside so much. There is nothing in this design that follows what we know listeners want: bass, even response, even directivity. And oh, some efficiency would be good too as I doubt someone wants to save money on a speaker and then wants to spend more to buy a powerful amplifier/receiver to drive it.
Very disappointing. Needless to say, I can't recommend the NHT Super Zero 2.1. If you need something this small, get a powered monitor as they have a far more optimized design than that is here.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
This is a very compact and rather dense speaker:
The back panel shows lack of any kind of port:
The finish is nice and glossy but the corners are very sharp which is not easy on the hand or measurements likely.
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 800 measurement which resulted in error rate of less than 1% throughout the range.
Temperature was 60 degrees F. Measurement location is at sea level so you compute the pressure.
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.
NHT Super Zero 2.1 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:
The most glaring issue he is lack of bass response which is due to lack of port and tiny enclosure. Second issue related to same factors is very low sensitivity. Third is poor directivity due to lack of any mechanism to get the beamwidth of the tweeter and woofer to match at crossover point:
The blue arrow shows the classic response of a tweeter (or any driver) as wavelengths get smaller. The tweeter gets progressively more directional. Same is happening to the woofer so we get a mismatch around 4 to 5 kHz. This then translates into our off-axis response being uneven and not match the direct sound:
Result is a response with a dip in critical range of music:
Combine that with lack of bass and this speaker will likely not sound good.
Directivity plots show what we have seen already:
Distortion story naturally is not good:
Finally here is our impedance and phase:
EDIT: forgot the drive response:
NHT Super Zero 2.1 Speaker Listening Tests
I hooked up the 2.1 to my main system placed on top of a stand for standard far-field listening. The sound was dead on multiple fronts: there was no volume making me crank my powerful amplifier to ungodly levels. Then there was no bass and I mean no bass. The moment the music would rely on bass notes to carry on, the sound level would go way down. Ditto for anything in 2 to 3 kHz range. A 3 dB boost in that region gave the speaker some lift but really, I was so unhappy with the experience that I shut everything off and that was all she told.
Conclusions
Amazing that a company like NHT that had a great reputation in the 1990s into 2000s has fallen by the wayside so much. There is nothing in this design that follows what we know listeners want: bass, even response, even directivity. And oh, some efficiency would be good too as I doubt someone wants to save money on a speaker and then wants to spend more to buy a powerful amplifier/receiver to drive it.
Very disappointing. Needless to say, I can't recommend the NHT Super Zero 2.1. If you need something this small, get a powered monitor as they have a far more optimized design than that is here.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Last edited:
