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Product Review - NHT 2.5i Floorstanding Speakers - September, 1997

James D. Moretti

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NHT 2.5i Floorstanding Speakers; Three-way design; One 1" aluminum dome tweeter, one 6 1/2" polypropylene mid-range driver, one 8" woofer; Crossover frequencies 100 Hz and 3.3 kHz; Vented box design; One 3" flared port on rear; Cloth grille; Frequency response 29 Hz - 25 kHz 3 dB; Sensitivity 86 dB/w/m; Nominal impedance 6 Ohms; Power handling 200 w-rms/ch; Bi-wirable; Size 38"H x 7"W x 15 1/2"D; Weight 46 pounds each; High gloss black: $1,300/pair; Also available in mahogany or sycamore: $1,350/pair; Now Hear This, 535 Getty Court, Benicia, California 94510; Phone 1-800-NHT-9993; Fax 707-747-1252; E-Mail 105277.3662@compuserve.com.

NHT means "Now Hear This", a clever name for a clever speaker manufacturer. Christopher Byrne and Ken Kantor formed the company only 10 years ago, and anyone interested in high end audio is familiar with their quality. The 2.5i is not a brand new speaker, and it was because it has such a nice reputation that we decided to get a pair and see just how good they are.

Our pair arrived in gloss black laminate, which is a welcome alternative to black vinyl. The most unique thing about their appearance is the 210 toe-in angle on the front. In other words, when the back of the enclosure is parallel with the wall, the front is toed in (see photo). This does several things. One is to reduce standing waves inside the enclosure, due to the front and rear being non-parallel surfaces. The other is to allow precise toe in, since all the user has to do is place them so the rear of the enclosure is parallel with the wall.

The mid-range driver is at the top, followed by the tweeter below. There is a vertical bar just to one side of the tweeter to reduce diffraction. The woofer is mounted to fire sideways, and is separated from the tweeter and mid-range by an internal baffle. The woofer enclosure has a 3" diameter flared port on the rear. The speakers have two sets of metal five-way speaker binding posts for bi-wiring or bi-amping. The speakers are very slim, so they have feet that stick out 2 1/2" on each side. Spikes can be attached at the outer edge of the feet.

I auditioned the 2.5is in our home theater lab, with a Yamaha LD Player, Yamaha RX-V990 Surround Sound Receiver, Yamaha DDP-1 AC-3 Decoder, Millennium DTS Decoder, and Carver AV-705 Power Amplifier. I also listened to them with the McCormack CD System, Balanced Audio VK-5i Preamplifier, and LLano SA-3 Monoblock Power Amplifiers. Cables were Tandy Gold Patch, AudioQuest, and Nordost Flatline.

Some speakers with side-mounted woofers allow you to place them with the woofers firing away from or towards center stage, since the speakers are symmetrical. However, the 2.5is are designed so that the speakers must be placed so that the woofers fire towards the center (facing each other). Of course, you can place them whatever distance apart is comfortable, but with the 210 toe-in, geometry determines the optimal placement so that you would be at the exact intersection of two lines drawn perpendicular to the front of the enclosure. What I found is that it is not critical. There was good off axis clarity, so you don't really have to get out that dusty old geometry textbook.

I tried everything from rock to classical, as well as some new laserdiscs and DVDs, and heard a variety of sound staging. The width of the stage was outside the boundaries of the speakers occasionally, but usually was confined side-to-side, between the speakers. However, all the CDs had nice front to back depth.

The 2.5is have modest sensitivity (86 dB/w/m) and intermediate nominal impedance (6 Ohms), so an amplifier with a good power supply is necessary. We did not have any problems driving them with the 125 w/ch Carver AV-705, and of course, the LLano SA-3s, with their 750 w/ch capability, were more than enough to drive them to high SPL. They sounded very neutral, with a slight bump in the 80 Hz - 125 Hz area, which translated to male vocals having a slightly accentuated depth.

I could get the woofer to bottom out with Copland's "Fanfare to the Common Man", but it took quite a bit to do it. I did not hear any tizziness in the highs (normal sibilance), and mids were clean. Bass was very tight, but not as deep as I would have expected. Of course, I love deep bass, and not many speakers, other than subwoofers, can give me the depth that I want (as you know, I play bass guitar for a living). On the other hand, the neutrality of these babies, without deep bass, is far preferable to the difficult-to-correct boominess, nasality, or chirpiness found in some other speakers.

At first, I was put off by the engineered toe-in, thinking this would restrict me from putting them where I wanted. But after hearing how focussed they were (pinpoint, with mono sounding dead center), I changed my mind. Instead of considering the design as having a lack of flexibility, I now think of them as preventing me from screwing up.

Frequency Response (Room Response), left channel only, 1 meter, on-axis, grille cloth on, volume set to 80 dB at 1 kHz :

20 Hz - 56.6 dB
25 Hz - 63.7 dB
31.5 Hz - 67.6 dB
40 Hz - 69.6 dB
50 Hz - 64.4 dB
63 Hz - 75.8 dB
80 Hz - 75.9 dB
100 Hz - 83.5 dB
125 Hz - 73.4 dB
160 Hz - 71.4 dB
200 Hz - 68.2 dB
500 Hz - 67.3 dB
800 Hz - 74.8 dB
1 kHz - 81.0 dB
2.5 kHz - 73.3 dB
5 kHz - 72.3 dB
8 kHz - 73.2 dB
10 kHz - 77.2 dB
12.5 kHz - 78.0 dB
15 kHz - 76.8 dB
18 kHz - 75.2 dB

Frequency Response (Room Response), left channel only, 13 feet, on-axis, grille on, volume set to 80 dB at 1 kHz :

20 Hz - 74.0 dB
25 Hz - 81.9 dB
31.5 Hz - 88.1 dB
40 Hz - 74.3 dB
50 Hz - 67.1 dB
63 Hz - 83.1 dB
80 Hz - 92.9 dB
100 Hz - 87.8 dB
125 Hz - 85.4 dB
160 Hz - 71.0 dB
200 Hz - 84.7 dB
500 Hz - 87.7 dB
800 Hz - 83.6 dB
1 kHz - 81.2 dB
2.5 kHz - 76.6 dB
5 kHz - 79.4 dB
8 kHz - 78.3 dB
10 kHz - 74.6 dB
12.5 kHz - 82.1 dB
15 kHz - 80.4 dB
18 kHz - 77.6 dB

You can see the bump in the 80 Hz - 125 Hz region that I heard. Probably something to do with the crossover. Nice response elsewhere. I have listened to a lot of speakers, and overall, the NHT 2.5is sounded more expensive than their price. My wife thought they were at least two grand for the pair. She is into the looks more than I am, and that piano black sure is great. I would tell you to audition the 2.5is, but you probably already have. If you are waiting for Secrets' official opinion, here it is:
Highly Recommended.

J.D. Moretti


Copyright 1997 Secrets of Home Theater & High Fidelity
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