NHT Model 1.3 loudspeaker Measurements

Sidebar 2: Measurements

I drove the Model 1.3s with a sinewave oscillator with my hand on the cabinet to detect resonances. They exhibited very few resonances, the loudest being at 140Hz and 330Hz. The 140Hz resonance produced a buzz, but was not as severe as the Tannoy E11's 220Hz peak.

The 1.3's impedance (fig.1) was lower than those of the Dana Model 1 or E11, at about 6 ohms through most of the low- to mid-frequency band. The narrow impedance peak at 66Hz reveals the 1.3's sealed-enclosure design. The Model 1.3's impulse response is very clean, with a minimum of ringing (fig.2). The step response (fig.3) rveals that both drive-units are connecetd in negative acoustic polarity, ie, the speaker inverts abolute polarity.

Fig.1 NHT 1.3, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

Fig.2 NHT 1.3, impulse response on tweeter axis at 48" (5ms time window, 30kHz bandwidth).

Fig.3 NHT 1.3, step response on tweeter axis at 48" (5ms time window, 30kHz bandwidth).

Fig.4 shows the Model 1.3's FFT-derived frequency response, averaged over a 30° lateral window. The nearfield woofer response, measured separately, is shown in the left side of the graph. This curve correlates with the listening impressions: good LF extension, smooth midrange, and a bright treble. The crossover-related dip between 3kHz and 4kHz is much less apparent off the direct axis, as is the rising response in the high treble. I preferred listening to the Model 1.3 about 20° off-axis. Fig.5 shows how the speaker's response changes to its sides, while fig.6 shows how it changes 15° and 15° below the tweeter axis. A suckout in the crossover region develops above the top of the speaker's cabinet, so don't audition these speakers on low stands.

Fig.4 NHT 1.3, anechoic response on tweeter axis at 48", averaged across 30° horizontal window and corrected for microphone response, with nearfield responses of woofer plotted below 300Hz.

Fig.5 NHT 1.3, lateral response family at 48", from back to front: responses 10–5° off axis on acute-angled side, reference response on tweeter axis, responses 5–15° off axis on obtuse-angled side.

Fig.6 NHT 1.3, vertical response family at 48", normalized to response on tweeter axis, from back to front: difference in response 15° above axis, reference response, difference in response 15° below axis.

The Model 1.3's in-room response, measured in JA's listening room for consistency with the speakers that he has reviewed, and spatially averaged to minimize the effects of room standing waves (fig.7), shows a very smooth midrange, good LF extension, slightly reduced energy through the mid/upper bass (100–500Hz), and a slightly tilted-up treble response. This correlates exactly with my listening impressions in my own room. Finally, the cumulative spectral decay plot (fig.8) is exceptionally clean and free from overhang, apart from the 1kHz region. The signal dies away very quickly in the treble, with only a few very minor ridges at about 4kHz and 7kHz. This is one of the better waterfall plots I've seen, regardless of price. (The dark ridge just below 16kHz is the computer monitor's scanning frequency, and not part of the loudspeaker response.)

Fig.7 NHT 1.3, spatially averaged, 1/3-octave response in JA's listening room.

Fig.8 NHT 1.3, cumulative spectral-decay plot on tweeter axis at 48" (0.15ms risetime).

Overall, this is excellent measured performance. The measurements also correlate very closely with what I heard during the auditioning.—Robert Harley

140 W. Industrial Way
Benicia, CA 94510
(800) 648-9993

TheAnalogkid's picture

I know mine look exactly like these but are the 1.5's. Maybe a diff tweeter or something.

4 NHT 1.5's, NHT SuperCenter, and my old trusty Velodyne ULD-15. Sounds great! Probably worth around $1k but would cost a lot to replace.

I had NHT 3.3's for 10 years until I finally upgraded to the GoldenEar Triton Ones. I loved the imaging, dynamics, and soundstage of the 3.3's but the GE Triton Ones do all of that and more. I waited a long time for a "bang for the buck" speaker to compete and I am not disappointed.

My wife says I traded a couple monoliths for a couple more monoliths, just a bit less imposing.

These are great times for the audio lover!!

DaveinSM's picture

I had the NHT 2.9 and it was a good speaker with very good bass that could play effortlessly very loud. But when I switched to Thiel CS 22, it was immediately apparent that they were better in flat frequency response, open, airy soundstaging, pinpoint imaging, and, to me, musicality. Those Thiels were just sweet speakers. The only area in which they could not match the NHTs was in max SPL and low bass slam. No contest there.

Anon2's picture

I appreciate the old reviews. It sometimes shows that a bargain might be had, if even to upgrade with new drivers from two of the excellent suppliers that we have in the US.

I would ask, when we will get more reviews of new stand-mounts? I don't mind having a German or Swedish or Polish translation lesson, because it's often what you have to do to get more reviews on new speakers.

The superb B&W 685 was never tested in this publication; the S2 is now two years old with no Stereophile review. The Amphion Argon has been around for over a decade; it now has a new upgrade. No review to be found in this publication. There is a new Dynaudio Excite X18 (to your credit you did review the X14); I hope a review is forthcoming. Sonus Faber has had the Olympica I out for a couple of years; I enjoyed what I heard from a brief listen. The exiting Dynaudio Focus 160 (and, yes, the non-amped Focus line is going away) got a blog/blurb, but never a full review.

I know you can't review everything. But there are some products that your competitors have reviewed--to high accolades--that never reach these pages.

Maybe mobile audio and hi-rez are now more prominent than speakers. Still, for many of us, speakers, and wide-ranging new speaker reviews, is an area of prime interest for any publication of our hobby. Please, we need more speaker reviews, preferably of new products. We don't mind the linguistic education we get from European websites to learn terms like "Spitzenklasse" and "überragend," and "Kvalitetsintryck," with help from Google. It's what I find myself doing more and more often when it comes to speaker reviews.

Fortunately, our British friends provide some relief with their more prevalent reviews of English-language stand-mount speaker reviews, some of which now have video content.

Please help, or explain what we're missing.

androman's picture

...Dynaudio excite x18 ,Amphion Argon 3s and Acoustic Energy reference 1, wonderful Air Tight Bonsai 2 are the kind of speakers this publication should be reviewing and not just to label them with A,B,C rankings but rather to arm readers with useful information on their character to make their purchase easier. That's what your audio readership is all about, Mr. Atkinson if you haven't figured out that one, yet. Then perhaps audio magazines wouldn't have to merge in order to survive on the market if you gave readers what they expect from an audio publicaton.