Type: Tower speaker
Configuration: 4-way bass reflex
Woofer: 10″ aluminum cone, 6.5″ aluminum cone
Midrange: 2″ aluminum dome
Tweeter: 3/4″ aluminum dome
Frequency Response: 27Hz – 20kHz
Crossover Frequency: 125Hz, 800Hz, 3.2kHz
Crossover Slopes: 12dB LP, 12dB HP 12dB LP, 12dB HP, 18dB LP, 18dB HP
Sensitivity: 86dB (2.83v@1m)
Impedance: 6 ohms nominal
Inputs: 2 each professional grade, with nickel-plated jumper straps
Tower Dimensions: 41″/1042mm x 5.5″/191mm x 16″/407mm (H x W x D)
Weight: 64-lbs./29.2 kg each
Finish: High Gloss Black or Special Dark Finish
[*For even better performance, the Four can be bi-amplified with NHT’s
optional A1 amplifier and X2 crossover]
I first requested the NHT Evolution 4000 for review about 10 months ago. They were the least expensive class A speaker in Stereophile’s recommended components list. I got an email that they would prefer me to review the top of their Classic speaker line. I agreed since it would fit into my quest to find good speakers to review for under $3000. I had not heard anything for about nine months, when I got a surprise call from the shipping department of the company I work for, saying that a pair of speakers had arrived for me. I took the speakers home and unpacked them. I received the special dark finish that was the color of dark cherry wood stain. I think that the cabinets are of a molded resin material. The finish quality was very nice and the speakers were of high build quality. Their small footprint makes them very useful for AV use. The tops of the speakers are curved down to the sides.
I was a little hesitant about aluminum drivers – they have sounded bright and brittle on other speakers. One of my prime considerations in the sound of a speaker is that they sound crisp and have a good sense of life. To me, most dynamic speakers sound slow, and take away from the live sound of music. The only dynamic tweeters that I have liked are the Avalon Diamond Tweeter and the beryllium tweeter used by Focal-JM labs. These are very expensive tweeters only included on expensive speakers. The NHTs were a big surprise. The sound is crisp and clean. The high frequencies have good extension. This is the biggest surprise – most dynamic speaker’s highs are neither extended nor detailed. The NHT are both. Most speakers are said to go to 20,000 hertz. This is usually +/- 3 or 6 dB. Minus 3 dB is one half of the volume. Most frequencies above 5000 Hertz are harmonics, which are usually lower in volume than the primary harmonic. This makes half or quarter volume have even a greater effect. I had a super-tweeter on top of the NHTs when a friend came over to listen to them – he thought the super-tweeter must be running. It was not connected, however. The bass is solid and reasonably deep. In my room the NHTs were very solid down to 40 to 50 cycles. You might say that that’s not that good, a lot of speakers say they go down to 30 to 40 cycles. Again specifications are very misleading. The measurements are taken at a one-meter distance, in a dead sound room and are usually +/- 3 to 6 dB. Most speakers are only good down to between 50 to 70 cycles in a real room. Smaller woofer speakers have even less extension in the lows. The imaging was solid and had power. The general presentation is smooth, yet having fairly good detail. The speakers have very good macro dynamics.
I will compare the NHTs to my reference under $5000 speakers and my reference speaker system. My reference speakers are the Eminent Technology LFT-8s. The NHTs have slightly better macro dynamics. They probably go down solidly about 15 to 20 hertz lower than the ETs. You do not have to worry about playing them really loud as you do with the ETs. The NHTs are much easier to deal with as far as space needed and room interferences. The ETs have better micro dynamics and detail. They also have a little quicker sound. The highs are slightly airier on the ETs. If the Thorough Bass (TB) subwoofers I use are added into the ET system, the system goes about 15 to 20 hertz lower than the NHTs alone and has better bass tonality. This is really an unfair comparison because the TB’s are what I consider the most tonally correct subwoofer I know of. They and their amps alone cost nearly twice as much as the NHT References Fours.
This is one of very few dynamic speakers under $5000 dollars that I would listen to for very long. Its small footprint and very good macro dynamics make it great for video use. I do not think you will get much better highs in a dynamic speaker without spending much more money on a pair. As for the bass, unless you spend thousands on a really good subwoofer or buy a much more expensive speaker, you will probably not get better bass. The speakers do take a while to break in – I would say a least 50 hours. Because of the rounded top I could not mass-load the speakers, which would have probably brought even more out of them. I also did not use the Tekna Sonic Speaker Dampeners on the speakers because I did not want to glue them on a speaker that I was not keeping. The Tekna Sonics would have also brought more out in the speakers. [Tekna Sonics just closed their doors; a real shame since their tweaks really worked!…Ed.] With these two tweaks, which I use on the ETs, the NHTs would have been even better. I can easily suggest listening to this speaker for anyone looking at speakers under $5000 a pair. The fact that it is a good-looking speaker is also a bonus. The build quality, sound and price make this speaker one of high dollar value.
— Clay Swartz