Definitive Technology SM45 Review

High Performance Bookshelf Speakers

It´s not every day we get to review a pair of studio monitors, and if the name is anything to go by, that is exactly what we´re dealing with here. But, the fact that the Definitive Technology SM45 uses a passive design makes them more suitable for use in a more traditional hi-fi system (with an amplifier) than a studio. Anyway, we hooked them up to a variety of amps to see and hear what they can do.

Design and Look

The price for a pair of SM45 is less than $400, which by high-quality bookshelf speaker standards must be considered quite cheap. With dimensions (H x W x D) of 11 11/16″ (29.69cm) x 6 3/4″ (17.14cm) x 11 11/16″ (29.69cm) they are small enough for a variety of situations and will look very nice on both shelves or stands. Despite being small, the fact that they are as deep as they are tall provides more volume inside the internally braced cabinet and should improve bass performance. The speakers does not include feet or spikes, but they do come with bumpers if you wish to protect the bottom surface of the speaker.

The cabinet is made of MDF and finished in a black vinyl wood veneer. Black is the only color available but the look and finish should complement the interior of most modern homes. The baffle is the only thing that visually stand out while also providing some acoustic benefits; the rounded edges help minimizing diffraction and reflections.

Definitive Technology SM45 bookshelf speaker
Definitive Technology SM45 baffle

Build Quality

Definitive Technology SM45 is a very well built speaker, something we wouldn´t expect at this relatively low price. The cabinet has internal bracing to reduce vibration and resonance, and although the speaker is a bit lighter than more expensive speakers of the same size it still feels stable and sturdy. A quick knock on the side of the speaker reveal that any dampening of the cabinet is well implemented, and the amount of vibration felt when placing a hand on the cabinet while playing music was minimal.

On the back of the speaker you´ll find a large reflex port and a single-wire terminal that can take the most common connector types. Thanks to the reflex port the lowest frequency limit is set to 35 Hz, which is very impressive for a speaker of this size.

The grille is removable to access the baffle and drivers. The holes that holds the grille in place are clearly visible when it´s removed, but the visual impact is reduced by the black finish.

Definitive Technology SM45 price

Under The Hood

The upper frequencies are handled by a heat-treated 1" (2.54cm) Pure Aluminum Dome coated with a ceramic and the lower frquencies are handled by a 5 1/4" (13.34cm) second generation BDSS (Balanced Double Surround System) midrange driver with a Linear Response Waveguide that smoothes off-axis frequency response and disperses sound over a wider area.

Definitive Technology SM45 speaker terminals

In short, Definitive Technology SM45 is a 2-way bookshelf speaker, not a studio monitor as the name suggests. Sure, you can use it for music production in a studio if you want to, but there are other speakers better suited for that job.

Sound Quality

The first time we listened to the SM45 we were surprised by how unremarkable they sounded - it was almost on the verge of boring. None of the music we played sounded as convincing or engaging as we were used to. So, we let the speakers play for a couple of days before returning to see (hear) if they perhaps needed some break-in. They did, and now they sounded a lot more appealing and captivating.

Definitive Technology SM45 bass reflex port

It took a few more days for them to loosen up completely, and after about a week we actually started to enjoy the laid-back yet natural sound. The sober presentation may come off as unimpressive to some, but we frankly prefer this type of speaker instead of one that´s always in your face and get tiresome to listen to after a while.

The bass, midrange and treble all play cohesively together without any particular frequency sticking out too much. Instead, the SM45 focuses on the music and provides good spatial information, making it easy to localize the specific instruments. The size of the stereo image is actually quite impressive for such a small speaker, and probably a result of the waveguide. The sound image remain fairly consistent even if you move out of the sweetspot, indicating that the SM45 would do a good job as part of a sourround sound system.

Compared to bigger and more expensive speakers, the bass obviously lack some power and weight, but on the other hand it is well balanced and never sound too much or boomy. This natural and neutral character makes the SM45 suitable for more 'mature' music, like classical and jazz for example, and the combination of great stereo imaging and details is what sets it apart from speakers trying to impress you with an overblown and aggressive playing style.

The neutral character is kept in check even when playing very loud, and although speakers of this size has obvious limitations when it comes to sound pressure and dynamics, it will take a hefty amount of volume before it starts to distort and sound bad.


For less than 400 dollars it is really hard to find anything wrong with the Definitive Technology SM45. With stellar build quality and a natural and honest sound they impressed us more than any other speaker we´ve listened to under $500.


  • IN ThE bOX
  • Second generation patented 5-1/4" BDSS mid/bass driver with Linear Response Waveguide technology for flat, accurate response with micro-detail retrieval and three-dimensional imaging
  • Second generation pure aluminum dome tweeter for smooth, extended highs
  • Non-resonant braced enclosure ensures pure, uncolored performance
  • High-gloss anti-diffraction baffle and shaped enclosures reduce diffraction for open and spacious imaging
  • Crossover network features oversize inductors and premium Mylar capacitors for audiophile-grade sound quality
  • Integrated Zobel network makes the SM45 easy for amplifiers to drive
  • Double-flared bass vent for extended bass response with low distortion
  • Heavy-duty 5-way binding posts ensure convenient and secure wire termination

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Old Price: $199.00
Current Price: $199.00