NSMT Model 15SE

REVIEW
by Steven Stone
May 13, 2022

If you look through a list of the products that I’ve reviewed during the last couple of years you’ll notice that most were newly released. That should not be too surprising since the vast majority of reviews in these pages are focused on new audio components and music. But sometimes there’s a component from a smaller audio firm that eludes our attention when initially released, but after further investigation deserves consideration. The NSMT Model 15SE ranks as one that I missed first time around.

NSMT is a U.S. loudspeaker manufacturer based in North Carolina, whose designer, Erol Ricketts, is also responsible for the designs in the Role Audio loudspeaker lineup. I have reviewed his Role Kayak loudspeaker, and it has been one of my nearfield reference monitors for years.

The $1995 NSMT Model 15SE could be considered a “big brother” to the Role Kayak. Like the Kayak, it is a two-way design, and like the Kayak, the Model 15SE does not use a port. This is part of Mr. Ricketts design philosophy, which you can read about on his NSMT site, where he has posted a series of white papers.

Tech Tour

I mentioned in the last paragraph that the NSMT Model 15SE is a two-way. It is also a first-order, time-coherent design. It uses a 6.5″ paper midrange/woofer combined with a 1″ soft-dome tweeter. According to NSMT, the woofer operates as a “crossover-less woofer with 6dB (first-order) crossover to tweeter consisting of a polypropylene capacitor and non-inductive wire-wound resistor.” In essence the crossover scheme is just complex enough to keep the drivers within their theoretical optimal linearity range. Any time-alignment between the tweeter and midrange/woofer on the 15SE is due to the physical arrangement of the drivers on the front baffle. The soft-dome tweeter is set back into the front baffle approximately 1½” and surrounded by a wide-flanged horn.

The beveled-edge front baffle of the 15SE is satin-black, one-inch-thick, anti-resonant MDF. The rest of the cabinet is three-quarter-inch Formaldehyde-free veneered MDF finished in a soft satin sheen. Like other U.S.-made cabinets, such as those from Omega, the 15SE has a thinner, more organic, more natural finish than the thick gloss I see on Chinese-sourced cabinets. NSMT’s water-based finish is also non-toxic, as is the lead-free solder used internally. With a single pair of five-way, gold-plated binding posts, biwiring is not an option with the 15SE.

Setup

Most of my listening was spent with the 15SE tethered to my nearfield reference system, but they also served time in my main room. I used the 15SE with several amplifiers including the LSA Warp 1, Clones Basic 25, Pass A30 monoblocks, and when I went to a room-based system, the Boulder 866 integrated—all via Audience Au 24SX speaker cable. In the nearfield system, I employed a Velodyne DD10+ subwoofer set to a 60Hz crossover point to mate with the 15SE. Nearfield-system sources included the Topping D90SE, Gustard X-16, and SMSL SU9 DACs. In my main room the Boulder 866 internal DAC and GoldNote DS-10+ were the digital sources. Analog came from a VPI TNT III with a Graham 1.5 tonearm, Clearaudio Victory cartridge, and Vincent PHO-8 phono preamplifier.

Setup on my desktop was simple. I have a series of dense foam risers that I use to adjust loudspeaker height; they allow for incremental alterations of approximately two inches per riser. During setup I immediately became aware of the 15SE’s limited vertical dispersion. With only one riser, the tweeter was too low; with four risers, it was too high; but with three risers, it was perfect. That placed my ears right at the center point of the tweeter horn. In this position I could move freely in my chair without any noticeable change in harmonic balance or imaging. While I usually use pink noise to determine the right speaker position, if you’re tired of that, you could use the “Tayos Caves, Ecuador I” from Jon Hopkins’ Music for Psychedelic Therapy, whose wind sound is an excellent stand-in for pink noise.

When I placed the 15SE in my room-based system, I crossed them over to a pair of JL Audio Fathom f112 subwoofers at 60Hz using the JL’s internal 24dB-per-octave high-cut filter. I used a pair of weighty 24″ Target stands, which placed my ears in approximately the same position vis-a-vis the tweeter’s as the desktop setup.

Sound

If I had to sum up the sound of the 15SE in one word it would be “right.” During first and all subsequent listens, these loudspeakers call attention to the music rather than to themselves. Even nearfield on my desktop, the 15SE soundstage sounds like it is emanating from behind rather than on a plane with the front of the speaker. Combine this with precise lateral image placement and a basically neutral, not overly lush harmonic balance, and you have a transducer that does an outstanding job of just getting out of the way.

The other loudspeakers that I’ve been using in my desktop system are a pair of brand-new, single-driver Omegas. What is surprising about these two transducers is how similar they sound. Both get the midrange right, with no audible crossover distortion. The Omega accomplishes this by not having a crossover! In comparison, the 15SE’s minimalist crossover also exhibits none of the audible tells that indicate its presence. Both also produce a similar soundstage, with its front edge beginning behind the loudspeakers themselves.

Many small bookshelves that take their lead from the classic LS3/5A with its ramped up upper-bass response. That’s not the 15SE’s path. The 15SE is more even in the lower midrange and upper bass than the LS3/5A. And while the 15SE does have substantially less midbass than the Alta Audio Allyssa loudspeaker I reviewed in Issue 320, the bass that the 15SE does have is smooth, without obvious irregular emphases. Also, in nearfield, near-wall setups, the 15SE has less tendency to get huffy, thuddy, or acquire excessive room-induced midbass sludge. In its bass response the 15SE is like a Role Kayak, but with an extra octave on its low end.

The upper-range limit of my hearing currently extends to 13kHz. Given my slightly truncated top end, the 15SE’s upper-frequency response managed to be resolving without sounding bright, and airy without sounding shrill. On bright, obviously poorly EQ’d recordings, the 15SE make me aware of their sonic failings without rubbing my nose in them. Because I listen to an extremely wide variety of music with wildly varying levels of sonic excellence, the 15SE’s made me aware of how good (or bad) a recording was, but it did this in a way that didn’t make me reach reflexively for the volume knob to turn things down.

Like any self-respecting audiophile I’m always searching for that extra iota of detail, definition, and sonic information that lies hidden in the back corners of a recording. The 15SE manages to scratch that particular itch nicely. With commensurately performing electronics, I never felt as if I were missing anything. Listening through the Topping D90SE DAC/Tortuga Audio LDR300x V3 passive preamp/LSA Warp 1 power amplifier signal chain got me as close to the music as any system I’ve heard—whether room or nearfield.

Ok, finding any decently designed currently available two-way desktop loudspeaker that doesn’t image well these days is difficult, and the 15SE does image well. But it goes further. To my ears, the 15SE not only gets the lateral placement correct but also delivers the dimensional cues and boundaries of sources in an especially three-dimensional manner. As long as the electronics in the signal chain can deliver sufficient signal to noise to render their electronic grain inaudible, the 15SE will generate an extremely enticing soundfield.

Comparison to an LS3/5A

The BBC-spec’d LS3/5A ranks as the archetypical two-way. It’s been available in one form or another for over 40 years. Since so many audiophiles have heard the LS3/5A, it’s an ideal transducer to compare with any other two-way monitor, so that’s what I did.

My pair of LS3/5As are from Sound Artist, which offers a Chinese-made version for around $600/pr. They are the least expensive and lowest-quality LS3/5As available. That doesn’t mean that they suck; just that when they’re compared to the Falcon or original versions, the Sound Artists are obviously not up to snuff. However, when compared to what else is available at a similar price and for similar applications, the Sound Artists are a competitive offering…and they sound like LS3/5As in terms of positives and negatives.

The 15SE is a far less colored loudspeaker than the Sound Artist. Unlike the LS3/5A, the 15SE doesn’t have the midbass hump that can give music more kick, especially rock-and-roll drum kits. The downside of this bass boost is that the LS3/5A quickly uses up the ability of the mid/woofer to get louder; thus, in essence, the LS3/5A has a built-in limiter. In comparison, the 15SE has much wider dynamic swings from loud to soft with greater contrast.

The LS3/5A has a certain sweetness to its harmonic presentation that makes bad recordings sound not quite as bad. The 15SE has far more of a straight delivery without sweetening. The LS3/5A’s harmonic character makes it a seductive loudspeaker, but between its subtractive dynamic presentation and additive harmonic warmth, it is certainly less accurate than the NSMT 15SE.

Summary

I suspect there are more choices in bookshelf loudspeakers than any other type. So, when it comes to monitors, audiophiles have many options. There are a myriad reasons to place the NSMT 15SE monitors among those that should be within your purview at under $2000 a pair. First, they are a solid, well-made loudspeaker with a classic driver array and a minimalist crossover scheme.

Second, the loudspeaker is designed and assembled in North Carolina by a small shop that does nothing but build loudspeakers. Finally, the NSMT 15SE can deliver reference-level sonics when mated with equally excellent components. So, if you are thinking of creating a system that requires a high-quality two-way monitor, if you don’t give the NSMT 15SE a listen, you’re missing out on an excellent high-value option.

Specs & Pricing

Type: Dynamic-driver, two-way, sealed-cabinet mini-monitor
Driver complement: 1″ soft-dome tweeter, 6.5″ paper-cone woofer
Frequency response: 55Hz–20kHz ±3.5dB (quasi-anechoic)
Impedance: 8 ohms (minimum impedance, 4.5 ohms)
Sensitivity: 87dB
Dimensions: 8″ x 14″ x 9.5″
Weight: 39 lbs. per pair
Price: $1995