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Definitive Technology StudioMonitor 55

Bookshelf speaker

29 Reviews | 5 questions - 20 answers


Our take on the Definitive Technology StudioMonitor 55

Don't let the StudioMonitor 55's size fool you — this compact bookshelf speaker belts out big bass that adds depth and richness to your movie soundtracks and stereo music. Each rock-solid cabinet features an advanced 6-1/2" mid/bass driver that's pressure-coupled to a top-mounted bass radiator for high-impact sound. Together, they provide more total bass radiating area than a 10" woofer, but with greater control, definition and speed than a single large cone. A 1" pure aluminum dome tweeter serves up crisp, extended highs that blend in beautifully with the mids and lows. The StudioMonitor 55 is the result of more than 20 years of research and development by Definitive in their quest to create speakers with a perfect balance of style, utility, and performance.

SM55 grille off

Get rich sound from a compact bookshelf design

Don't let the StudioMonitor 55's size fool you — this compact bookshelf speaker belts out big bass that adds depth and richness to your movie soundtracks and stereo music. Each rock-solid cabinet features an advanced 6-1/2" mid/bass driver that's pressure-coupled to a top-mounted bass radiator for high-impact sound. Together, they provide more total bass radiating area than a 10" woofer, but with greater control, definition and speed than a single large cone. A 1" pure aluminum dome tweeter serves up crisp, extended highs that blend in beautifully with the mids and lows. The StudioMonitor 55 is the result of more than 20 years of research and development by Definitive in their quest to create speakers with a perfect balance of style, utility, and performance.

BDSS driver

Definitive's second-generation patented BDSS driver

High-tech driver design for impressive performance

The StudioMonitor 55 is chock full of technology that's also found in Definitive's top-of-the-line speaker models. Its 6-1/2" mid/bass driver uses their latest Balanced Dual Surround System (BDSS) driver design, which places a surround on both the outer and inner edge of the speaker cone. This helps the cone remain more stable as it moves, resulting in clearer, more accurate sound — even at high volume levels. The '55's mid/bass driver also gets Definitive's second-generation Linear Response Waveguide™. This mushroom-shaped post in the center of the cone smooths off-axis frequency response for broad, even sound dispersion and a more realistic sonic "image." That means every listener in the room gets to hear balanced, open sound with lifelike vocals and instruments.

sm55 tweeter

A second-generation pure aluminum dome tweeter yields smooth, extended treble.

Crisp, sparkling highs

Definitive also equipped the StudioMonitor 55 with their latest 1" pure aluminum dome tweeter. This advanced driver is first heat-treated to relax the crystal structure of the metal, then coated with a ceramic that helps produce clear, sparkling highs without a trace of edginess. You'll easily hear the subtle high-frequency details in your music, like the sound of wire brushes gently sweeping the snare head, or the bell-like ring of a brass cymbal.

SM55 bass radiator

A top-mounted bass radiator provides outstanding low-frequency response.

It's all in the details

Definitive paid close attention to other important design elements, too — both visible and hidden. At its heart, the StudioMonitor 55 uses a sophisticated crossover network with audiophile-grade components that include over-sized inductor coils and Mylar film capacitors. These give you a smoother, flatter frequency response, more powerful dynamics, and faster transients, for sound with real presence and immediacy. Sturdy, vault-like cabinet construction also plays a big role in this speaker's performance. The '55's well-damped, cross-braced enclosure features a specially contoured front baffle with tapered sides to minimize diffraction and vibrations that can color your sound and reduce accuracy.

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Did you know?
Your new speakers will probably sound better after several weeks of use than they do right out of the box. That's because the material surrounding the woofers will loosen up, allowing the drivers to move more fully. Definitive Technology estimates a break-in period of 24 to 48 hours of playback before the speakers will deliver optimum sound quality. For more information and helpful tips, check out this article from Definitive's website about conditioning your speakers.

Unbelievably good speakers for the price. Very nice bass extension too. I use them as fronts for a 5.1 system in a medium sized family room. Couldn't be happier.

Brad, Wixom, MI

What's in the Box:

  • Black bookshelf loudspeaker
  • Detachable black cloth grille
  • 2 Jumpers (attached to speaker terminals)
  • 4 Self-adhesive rubber feet
  • Owner's Manual
  • Online Product Registration card

Product Highlights:

  • second-generation Balanced Dual Surround System (BDSS) 6-1/2" mid/bass woofer for clear, accurate sound at high volumes
  • Linear Response Waveguide technology smooths off-axis frequency response provides broad, even sound dispersion and more realistic imaging
  • rigid die-cast aluminum driver basket resists vibration and twisting for lower distortion
  • top-mounted bass radiator for outstanding low-frequency response
  • second-generation 1" pure aluminum dome tweeter delivers clear, extended highs
  • crossover network features oversize inductors and premium Mylar capacitors for audiophile-grade sound quality
  • non-resonant braced enclosure ensures clean, uncolored sound
  • wood grain matte black enclosure with high-gloss, anti-diffraction baffle and detachable cloth grille
  • frequency response: 32-30,000 Hz
  • sensitivity: 90 dB
  • impedance: 8 ohms
  • recommended amplifier power: 20-225 watts
  • dual 5-way binding post speaker terminals for bi-wiring and bi-amping options
  • 12-15/16"H x 7-7/8"W x 12-1/2"D
  • warranty: 5 years
  • Our 60-day money-back guarantee

Definitive Technology StudioMonitor 55 Reviews

Average Customer Review(s):

(29 Reviews)
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Hands-on research

Features and Specs

Enclosure Passive Radiator
Video Shielded No
Tweeter Type Dome
Tweeter Size (inches) 1
Midrange Size (inches) N/A
Woofer Size (inches) 6.5
Woofer Composition Polymer
Woofer Surround Rubber
Power Range 20-225
Sensitivity 90 dB
Impedance (Ohms) 8
Frequency Response 32-30k Hz
Connector Type Post
Bi-amp Inputs Yes
Height (inches) 12-15/16
Width (inches) 7-7/8
Depth (inches) 12-1/2
Weight (pounds) 15.5
Mounting Bracket Included No
Recommended Stand Height (inches) 28.5
Parts Warranty 5 Years
Labor Warranty 5 Years

Product Research

Driver Technology
Enclosure Design
Mounting Options

Driver Technology

StudioMonitor Series: The Definitive Technology StudioMonitor 55 is a compact bookshelf loudspeaker designed for use in audio/video entertainment systems. Because the StudioMonitor 55 is a true full-range speaker with extended low-frequency response, it delivers superb performance both as stand-alone speaker and when combined with a separate subwoofer. Due to its compact size, wide-range, high-power handling, and natural articulate clarity; the StudioMonitor 55 loudspeaker is ideal for use as front, center, or surround speaker in a home theater environment.

2-Way Loudspeaker: Each Definitive Technology StudioMonitor 55 loudspeaker features a 6.5" second generation BDSS cast-aluminum basket midrange driver and a 1" pure aluminum dome tweeter.

  • 2nd Generation BDSS Midrange: The 6.5" cast-aluminum basket midrange driver features Definitive's patented Balanced Double Surround System (BDSS) technology that supports the speaker cone at both the inner and outer edges allowing longer, more linear excursion for greater clarity and finely textured inner detail.
  • Pure Aluminum Dome Tweeter: The 1" tweeter is a pure aluminum dome, which has been heat-treated to relax the crystal structure and then coated with a ceramic to produce smooth, extended highs. A new patent pending Linear Response Waveguide smoothes off-axis frequency response and disperses sound over a wider area for crystal clear intelligibility for every listener in the room.

Pressure Coupled Radiator Design: The 6.5" BDSS midrange driver is pressure coupled to a top-mounted 6"x10" racetrack bass radiator to extend and amplify bass frequencies. The total bass radiating from a StudioMonitor 55 is substantially greater than that of a single 10-inch woofer but with far greater control, definition and speed than a single sluggish large woofer. The StudioMonitor 55 speaker's bass performance offers depth, detail, and musicality.

Note: Due to the top-mounted racetrack bass radiator, there should be at least 2" of space above the bookshelf loudspeaker.

Phase-Coherent Crossover Networks: The crossover network is the real heart of a loudspeaker as it is responsible for perfectly blending together the sound of the various drivers into a musically seamless whole. The sophisticated crossover network design used in the StudioMonitor 55 loudspeaker features premium audiophile-grade components; such as oversized inductors and Mylar capacitors for audiophile-grade sound quality, with linear phase and frequency response. An integrated Zobel network flattens the impedance of the system so that even budget amplifiers will be able to drive the StudioMonitor 55 loudspeaker (although a premium amplifier will bring out all the performance it has to offer). As a result, the audio signal's phase coherence, transient response, and dynamic integrity is preserved for absolutely lifelike music and home theater reproduction in your home.

Enclosure Design

Non-Resonant/Low-Diffraction Cabinet: The Definitive Technology StudioMonitor 55 bookshelf loudspeaker employs a non-resonant MDF braced enclosure that ensures pure, uncolored performance. The specially contoured high-gloss baffle around the drivers and the tapered enclosure sides enhance sound quality by minimizing diffraction distortion.


Bi-amp/Bi-wire Binding Posts: Each StudioMonitor 55 bookshelf loudspeaker has two sets of heavy-duty, all metal binding post speaker terminals (connected by metal jumpers) to attach your receiver's speaker wire. Using the dual binding posts, you can bi-amp or bi-wire the speakers for even better sound. The binding post speaker terminals will accept bare wire (up to 10AWG), pin-connectors, spade-connectors, and banana-plugs (single only).

Color-Coded: The speaker's binding posts are color-coded (red/black) for easy identification between positive and negative.

Mounting Options

Table-Top Mounting: The StudioMonitor 55 loudspeaker can be simply placed on a bookshelf, table-top, or speaker stand (such as the Definitive Technology StudioStand, sold separately ). Four self-adhesive rubber feet are included to protect your furniture's surface.

Wall Mounting: The optional PinPoint heavy duty side-grip wall-mounting bracket (121AM41B, sold separately) can be used to wall mount the speaker.

Note: The speaker does not include any type of wall-mount bracket, threaded inserts, or keyhole slots.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

Superb speakers for a pretty tight space. Replaced (old) large Infinity floor models and sound better in many ways. [ S  Jun 11, 2017 ]
Good product, reviews, support. [ Tim  Apr 19, 2017 ]
Ratings by both customers and audiophile media that match my need for clear articulation of dialog, background and placement of instruments/vocalists. As a bonus, higher efficiency and deep base (thanks Larry for pointing this out). [ Michael  Mar 20, 2017 ]
Sale price and already have a DT sound bar [ duane g.  Mar 13, 2017 ]
I recently purchased one set of DT-Studio 55s for my A/V system. This is the second set for the other end of the room. Next could possibly be a center channel or sub woofer. [ J.  Feb 16, 2017 ]
These speakers seem so much bigger than bookshelf speakers. Crisp highs and warm mids. A surprisingly low db reaching speaker. Would recommend to anyone avoiding the towers. [ Robert  Aug 11, 2016 ]
You used to be able to go into an audio store and actually LISTEN to speakers and make a selection. Today, you have to go by specs and user comments. In the case of the Def Tech 55s, the specs are impressive and user comments, although sparse, were favorable. We'll see when I get them in the house and set up. [ James  Mar 29, 2016 ]
I like the sound of these speakers over others in there price range [ JOHN  Dec 19, 2015 ]
I was searching for bookshelf speakers to fit into a TV storage unit I installed, and these are well regarded speakers that match the sound quality of the speakers I already own. In addition, the discounts running on them helped bring the price down and made the decision easier. [ Eric  Dec 10, 2015 ]
These Monitors offer increased Bass (30 vs44) and Treble ( 30,000 vs 24,000) response to complement by Polk floor standing speakers already in place to widen my marches on.......oh, Joy...and as has been the case for over 25 years, I have complete faith in the Price, Value, and Quality from "The Crutch"! [ Dennis K.  Dec 07, 2015 ]

5 questions already asked

@LeoD I have these speakers and they are fantastic. Great bass and mids for a bookshelf. As far as hanging them on the wall I dont think this would work well, they are pretty hefty and heavy. Plus, the sub thats built in needs some wall to get the reflection. I have mine on a bookshelf (ironically) and with a Definitive sub and center channel its perfect for a 5.1 system in a normal living room. If you want to hang/mount these I would go with smaller satellite speakers if you have bass covered with a cube already. [ Dominic  Apr 28, 2017 ]
No sir, no problem because these are full bodied speakers and that's exactly where i have mine. Great sound. But uf tou really want to do something special with your home theater, add a definitive tech powered center speaker [ DORAN L  Apr 28, 2017 ]
My SM55 speakers are only 8 inches away from my TV on both sides. I had the same concern when I bought mine. I've no problem at all. I am completely happy with the performance. [ James  Dec 21, 2015 ]
I have these as front speakers in a wood cabinet under my TV and there is zero impact on the picture. [ Andrew  Dec 21, 2015 ]
You shouldn't have interference problems at all unless you have an older CRT model.My StudioMoniters are only 8" from our LCD TV and work great.Im sure you will be very happy with choosing the StudioMoniters,great speakers! [ Dolan  Dec 21, 2015 ]
I have a Def Tech Super cube that sounds great! [ Andrew  Dec 21, 2015 ]
I have an older Polk Audio Subwooferr which works extremely well with this speaker [ JULIO C  Jul 17, 2015 ]
The answer to your question is base on your room size and bassholic level. Go to svsound and use their merlin tool to match a svs sub with the SM55. I used my SM55 as surround speakers so they don't have to work as hard compare to a stereo setup. In conclusion, listen to the SM55 before you buy them to judge if they generate enough bass for you. [ DAVID  Jul 17, 2015 ]
Bi Amping: It only makes sense if you have an amplifier that allows you the ability to separate the output in two sections, one for the tweeter and the other for the woover, otherwise it's just so to speak adding bigger gauge speaker cables. [ MusicHeaven  Sep 13, 2015 ]
Hello, I do not know. I h e not used bi amping. [ Terry  Mar 11, 2015 ]
Sorry, I have no idea what "bi-amping" is. [ JAMES EDWARD  Mar 09, 2015 ]
It works great bi-amped. Is a great option for this Def Tech. I love it!!! [ VictorAriel  Mar 09, 2015 ]
The speaker does provide extra terminals for this purpose. However I really am not convinced that the extra effort and expense is worth any perceived benefit, which I suspect may be imaginary. Perhaps a more elaborate speaker system might warrant it. I would put the money in a better sub woofer or amplification. That said I find the performance of this speaker to be superb' and not in need of bi- wiring, or bi-amplification. [ Thomas R.  Mar 09, 2015 ]
George, I have not bi-amped the 55's yet, but I plan to, just have to spring for the right receiver/amp. I have read all the literature and the 55's are set up for bi-amping and should benefit from it. Bi-amp the 55's then add the Definitive Tech super cube bass. That sound would be outstanding. [ JOHN  Mar 08, 2015 ]
I would venture to say: Yes, it's a good option. I am driving mine with an Onkyo receiver (which doesn't allow for bi-amping) because it has the ability to receive radio streams via its Vtuner function. But, having owned audiophile speakers (Maggies) and C-J electronics, I can sense that these speakers could deliver much more satisfying sound if only they were provided with better-defined signals. So, if you can bi-amp the speakers, I would advise you to go for it. [ PHILIP S  Mar 08, 2015 ]
I never tried it and they sound great. I use them as my front speakers [ KYLE  Mar 08, 2015 ]
"Definitive ProCenter 2000 (BK) Center Channel Speaker Item #: 735PCTR2KB" This is the speaker I used. I like it. Definitive may have some better speakers, but this is all my pocket book would stand at the moment. I use a Yamaha receiver to run my speakers. [ JAMES EDWARD  May 06, 2014 ]
As you should always match brands on all speakers for a multi-speaker setup, I suggest going to the Definitive Technology website and check out their center channel speakers. Something like the CS-8080HD, CS-8060HD, or CS-8040HD should blend nicely with the SM55 speaker, all which are available at Crutchfield. [ PHILIP  May 05, 2014 ]
I am using the Def Tech CS 8040 HD in my set up. I have SM 65's for the mains and SM 55's for surround. All work in perfect unison. [ ERIC  May 05, 2014 ]
Use the SM-65 in horizontal position. That's what I do and it sounds perfectly matched. [ Grisha Goryache  May 05, 2014 ]