Test Report: Definitive Technology StudioMonitor SM65 and SM45 Speakers & Supercube 8000 Subwoofer

When I’m looking for speakers to review, I gravitate toward two types: ones that have the potential to sound great, and ones with weird designs. The former offer the potential for hours of joyous listening. The latter offer the potential for either a previously unimagined sonic nirvana or an audio train wreck, both of which are fun to write about.

Definitive Technology’s $899-per-pair StudioMonitor SM65 fits both descriptions.

 Its brand name suggests excellence; I can’t recall hearing a bad DefTech speaker. Yet the SM65 also offers the potential for weirdness because of its huge, top-mounted passive radiator and its unusual new midrange/woofer drivers.

DefTech deployed the 6-by-12-inch passive radiator to give the SM65 deeper bass than most bookshelf speakers can muster. Passive radiators are tuned to resonate below the operating range of a speaker’s woofer, so they extend the speaker’s deep bass. Kind of like a voiceover actor hiring James Earl Jones to come in and do the lowest notes for him.

The midrange/woofer sports one of the biggest phase plugs I’ve ever seen. A phase plug, which sits in the same place as a regular driver dust cap but is attached to the pole piece and not the cone, minimizes interference of high-frequency sound waves inside the driver’s cone. DefTech’s new Linear Response Waveguide phase plug is far bulkier than the usual cone-shaped metal phase plug — and for some reason, it’s rubber-coated.

The midrange/woofer’s cone also has an unusual double surround: an extra butyl rubber ring that attaches the cone to the voice coil and earns the driver its Balanced Double Surround System moniker. The company says this design (which it has used in previous drivers) allows greater cone excursion and lower distortion.

The SM65 is the flagship of the StudioMonitor line, DefTech’s first new bookshelf speakers in nearly 10 years. It contains two 5.25-inch midrange/woofers and a 1-inch aluminum dome tweeter. The middle model, the $599-per-pair SM55, has the same tweeter, a 6.5- inch midrange/woofer, and a 6-by-10-inch radiator. The smallest speaker, the $399-per-pair SM45, uses the same tweeter with just one of the SM65’s 5.25-inch midrange/woofers and a rear-fi ring port instead of the radiator. DefTech makes three center speakers suitable for use with the StudioMonitors: the CS-8080HD, CS-8060HD, and CS-8040HD.

Even though the SM65’s purported 30-Hz bass response should let non-bass-freaks get by without a subwoofer, DefTech hedged its bet by sending me its new top-of-the-line sub, the $1,499 SuperCube 8000. The SC8000 incorporates an 11-inch active woofer, two 12-inch passive radiators, and a 1,500-watt “digital tracking” amp. (I take it that means a digitally controlled Class H amp, not a Class D switching-type amp.) No auto-EQ, but at least it has four EQ presets intended to tailor the sound to your taste.

Okay, now it’s time to find out what we’ve got here: great sound, or...?


DefTech sent me enough speakers so that I could set up a 5.1 home theater system: three SM65s for the front left, center, and right channels; two SM45s for the surround channels; and one SuperCube 8000.

Setup was simple. I plopped the three SM65s on 28-inch-high stands in a line below my projection screen and pointed them all straight at me. Same thing for the surrounds, which also went on 28-inch stands placed along the side walls, slightly behind my listening position. I tried listening with and without the grilles, and ended up doing most of my listening without. One caveat: If you’ve established a habit of leaning on a speaker by placing a hand on top, either break the habit or you’ll break the plastic frame of the grille covering the SM65’s passive radiator.

I put the SuperCube 8000 in my subwoofer sweet spot, the place where most subs sound best from my usual listening position. The large front display and the included remote control made it easy to set level, crossover point, and EQ from my listening chair. Another caveat: The LFE input does not bypass the internal crossover, so if you’re using this sub with an A/V receiver or processor, you have to remember to set the sub’s crossover frequency as high as it’ll go (150 Hz).

CyberAthlete's picture

Thank you very much for the review! I went the same route. 3x SM65 for the fronts and center, and 4x SM45 for the surrounds. Did you get a chance to place the SM65 horizontally? That is the only way I can place the center since the screen is only 9" higher than the AV media table.