Definitive Technology Bipolar BP-8040ST 5.1-Channel Speaker System (TPV 108)

Definitive Technology BP-8040ST,
Definitive Technology CS-8040HD,
Definitive Technology SR-8040BP
Definitive Technology Bipolar BP-8040ST 5.1-Channel Speaker System (TPV 108)

In pop psychology the term “bipolar” describes a personality disorder, but in loudspeakers it references a design format known to yield giant, spacious soundstages—one of the very qualities we like most about Definitive’s Bipolar BP-8040ST surround system ($2595). Bipolar loudspeakers, as many of you know, feature both forward and rearward-firing driver arrays—an arrangement that offers several benefits, among them more even power response throughout the room, plus a tendency for that rear wave of acoustic energy to reflect off the wall behind the speakers creating a convincing illusion of expanded soundstage width and depth.

Bipolar speakers are as much a part of Definitive Technology’s corporate identity as, well, the word “Definitive,” since the very first speakers that put the company on the map were bipolar models and there have been bipolar models in the lineup ever since. Thus, whenever Definitive chooses to update its bipolar range—as happened just about a year ago—it takes great care to get the designs right, since in a very real sense they tend to be the standard bearers against which the entire company may be judged. Definitive’s newest bipolar lineup centers on four floorstanding models, starting with the diminutive BP-8020ST and ranging on up to the mighty BP-8080ST. In a recent conversation with Definitive’s Senior VP of Marketing and Product Development Paul DiComo, I learned that he commends the one-up-from-the-bottom-of-the-line BP-8040ST as offering exceptionally good bang for the bucks within a product line already known for value. Indeed, DiComo has lived quite happily with a set of BP-804ST’s in his home system, even though he could bring home pretty much any Definitive model he wants.

I explained to DiComo that The Perfect Vision was interested in reviewing either a maximum performance bipolar surround system, or one that in his estimation offered maximum performance per dollar, and without hesitation he suggested the BP-8040ST based system reviewed here. The system consists of a pair of BP-8040ST floorstanders ($1598/pair), a CS-8040HD center channel speaker ($499), and a pair of SR-8040BP surround/FX speakers ($498/pair). No separate subwoofers are needed as each of the BP-8040ST’s contains a built-in, 300-watt powered subwoofer.

Before we jump into the review proper, though, let me summarize some of the technologies used in the BP-8040ST and other Definitive bipolar systems. The main speakers feature both front and rear-firing driver arrays, but unlike earlier Definitive bipolar models, those arrays are now deliberately asymmetrical, meaning that they use similar but not identical arrays on the front and back. Why the asymmetry? Definitive research suggested that it would be a good idea to have more output radiated from the front of the speaker than the back, partly because this arrangement was thought to give the best combination of imaging precision and focus, while still preserving the broad, deep soundstages for which bipolar technology is known.

Next, the BP-8040ST provides a built-in powered subwoofer with user adjustable output level controls—a feature it shares in common with other BP-ST models (where “ST” denotes Super Towers, which by Definitive tradition feature onboard powered subs). In practical terms, this arrangement means that surround systems based on BP-ST models will automatically have not one but two powered subs for more powerful and even distribution of low bass throughout the room.

Finally, all BP-ST models features unexpectedly slender tower-type cabinets, cabinets that in the case of the BP-8040ST offer footprints that takes up less than a square foot of floors area. When most people hear the word “floorstander” they imagine speakers that will be big and bulky, but that isn’t the case at all with the BP-8040ST’s, which seem very slim and compact.

But enough of background information; let’s look at how the BP-8040ST system is made and sounds.


BP-8040ST floorstanding speaker system, technical highlights:

•Front-firing driver array: one 1-inch aluminum dome tweeter and two 3.5-inch BDSS mid/bass drivers.
•Rear-firing driver array: one 1-inch aluminum dome tweeter and one 3.5-inch BDSS mid/bass driver.
•The aluminum tweeter is the same design that debuted in Definitive’s Mythos ST and STS models, a design that offers noticeably smoother treble response than Definitive’s earlier aluminum dome drivers did.
•The BDSS midrange driver is new-generation version of the BDSS driver that first appeared in Definitive’s ProCinema and Mythos-series speakers some years ago. The BDSS driver design features a cone-shaped driver diaphragm with a hole in the center and which is supported both by inner and outer surround rings (the inner surround ring anchored to a centrally positioned, fixed pole-piece that doubles as a waveguide). The BDSS design was originally developed with an eye toward improved power handling, but turned out to have other key benefits in terms of a significantly more responsive and open sound than many midrange drivers can produce. New in this second-generation BDSS driver is a large flared, golf tee-shaped central pole piece that is said to dramatically enhance midrange dispersion.
•Woofer driver array: one 8-inch powered woofer and two 8-inch passive radiators, driven by a built-in 300-watt amplifier.
•The woofer amp provides a built-in active crossover and a user-adjustable level control, plus a separate LFE input for those who may wish to drive the subwoofer from the LFE outputs of their A/V receivers or controllers.
•In practical terms, the active woofer system makes the BP-8040ST extremely easy to drive, since the user’s main amplifier never really drives the woofer array in the usual sense of the word. Instead, the user’s amp simply provides what amounts to an input signal so that Definitive’s onboard amp can take over the bass workload from there.
•The BP-8040ST, like all BP-series models, features a slender, black fabric-wrapped enclosure with a gloss-black endcap on the top, and a gloss-black floorplate and trim panel at the bottom. To improve stability (and thus tip-over resistance), Definitive also provides a set of four slim, bolt-on stabilizer feet that can be fitted with included floor spikes.

CS-8040HD center channel speaker, technical highlights:

•Driver complement: one 1-inch aluminum dome tweeter, two 4.5-inch BDSS mid/bass drivers, and one oblong, upward-firing 5-inch x 10-inch passive radiator, which is said to increase bass extension.

SR-8040BP surround/FX speaker, technical highlights:

•Bipolar driver array: two 1-inch aluminum dome tweeter, two 3.5-inch BDSS mid/bass drivers.
•The SR-8040BP feature an angled, almost V-shaped face that provides proper mounting surfaces for the bipolar driver array, with one half of the array angled forward and the other half angled backward.


The BP-8040ST system’s overall sound takes its cues from the voicing of the BP-8040ST super towers, while offering an excellent degree of voice matching from channel to channel within the system.

The sound of the BP-8040ST centers on a midrange that offers a good combination of openness, natural warmth, and surprisingly full-bodied dynamics—qualities that in a very real sense are mirrored by the rest of the speaker system. The midrange array offers good measures of transparency and detail, but its greatest strength may be dispersion and an ability to set midrange frequencies free from the confines of the super tower cabinets. It is aided in this effort by the rear-firing bipolar array, which adds significant width, depth, and balance to the overall presentation.

The aluminum dome tweeter gives unexpectedly smooth and decidedly non-metallic-sounding highs, and it integrates very well with the BDSS mid/bass driver. But with that said, let me add that the tweeter does not seem to me to offer quite the last word in treble transient speed or detail, so that in comparison to some tweeters I’ve heard it does seem to leave small bits and pieces of treble information “on the table,” so to speak. But while the tweeter may leave detail mavens wishing for a bit more, the good news is that its inherent smoothness enables the speaker to work well even with material that might make some competing speakers sound “hard” or “edgy” by comparison.

The woofer system of the BP-8040ST is terrifically well conceived and is a fine performer. If you’re in the habit of setting your performance expectations by visually gauging the volume of the speaker enclosure, then I can pretty much guarantee that the BP-8040ST will blow your mind, because this relatively compact speaker offers bass output that is both vigorous and that offers serious low-frequency extension. Even in moderately large rooms, the BP-8040ST’s had no trouble at all in handling large-scale low-frequency sound effects without apparent distress (well, except for others in the house who might be put off by thunderous sounds emanating from the living room). Credit for the 8040ST’s low frequency clout must go in large part to the speaker’s clever amplifier design, which is capable of selectively applying momentary compression on select frequency bands in real-time, while leaving other frequency bands untouched.

The BP-8040ST’s bass is slightly, but only slightly, more warmly voiced than the bass you might hear from, say, Definitive’s excellent Mythos ST or STS speakers. I suppose this might be attributable to the fact that the BP models use cabinets made of MDF, while the Mythos models use exceptionally rigid extruded aluminum enclosures. In a strict, textbook sense (and in a pursed lips, furrowed brows, “let’s concentrate like crazy on what we’re hearing” audiophile sense), the Mythos approach to bass is arguably more accurate, but my sense is that a great many listeners will actually prefer the BP’s bass because it sounds more immediately hearty, powerful and accessible.

Just for the record, let me add that the CS-8040HD is a real corker of a center channel, too, in that it A) matches the voicing of the super towers well, and B) provides—as do the super towers—a sense of effortless, free-flowing dynamics. In theory you could probably overload the center if you really pushed things to the limit, but this would likely occur at volume levels most households would find intolerable in the first place.

Finally, the SR-8040ST’s do what you would want any good surround speaker to do, which is to convey surround channel information without drawing much if any attention to themselves, and without messing up the voicing of the rest of the system.

But in a big picture sense, what the BP-8040ST does better than it has any right to for its size or price is to produce huge, wraparound surround soundstages without—and this is the hard part—losing imaging specificity or focus. I really think Definitive is on to something good with its asymmetrical bipolar arrays, as this system (as compared to the last Definitive bipolar speakers I reviewed some years back) offers stable, well focused images while at the same time creating the illusion of superb stage width and depth. As a result, your ears are never drawn the super towers themselves, but rather are drawn to the three-dimensional wall of sound unfolding across and behind the front wall of your listening space. This big, seamless “wall of sound” is really one of the main reasons people buy bipolar speakers for in the first place, but with the new BP design the sheer size and scope of the stage is complemented by levels of imaging precision the earlier BP models could not match.


To give the BP-8040ST system a dynamic workout, I played the “Games” chapter of the Blu-ray version of Tron Legacy. The BP-8040ST’s did a very nice job with the throbbing synth bass passages heard in the beginning of the scene as white-clad female “programs” dress young Sam Flynn to prepare to do battle with other “programs” in the games on the grids. But as one of the robot-like programs observes while preparing Flynn’s armor, “he is different” (because, of course, Flynn is not a program at all but rather a human “user”). Yet on that particular bit of dialog, and also in the general sound effects that accompany the scene as the programs dress Flynn, astute observers will notice that the Definitive system’s upper midrange/treble detailing is not quite as focused as one might wish.

For example, the sound of the program’s voice saying “he is different” should sound unmistakably phase-shifted, a fact that is not at first as clear as it might be through the Definitive rig owing to the system’s slightly subdued-sounding highs. Similarly, as the four white-clad programs approach Sam Flynn, the click of their footsteps should plainly echo and reverberate through the dressing room, emphasizing Sam’s isolation and aloneness. But while those echoes are audible through the Definitive system, they are not as distinct as they could be, and in some systems would be. The good news, however, is the once the games begin, the sheer dynamic swagger and spatial presentation of the BP-8040ST comes to the foreground, making it easy for the viewer/listener to suspend disbelief and to buy into the otherworldly techno-environment of the Grid, which is the setting for almost all of the action in the film.

I also turned to one of my favorite (and most demanding) surround sound test films; namely, the academy award-winning picture, The Hurt Locker. The movie allows the full spectrum of the BP-8040ST’s to shine, but also exposes those areas where the speaker system’s performance could be even stronger. In the film’s opening chapter, for example, where we see an attempted bomb disposal mission go horribly wrong, the spatial characteristics of the BP-8040ST do a good job of capturing the swirling, shifting turns of events where a tense situation quickly unravels as a shopkeeper-turned-terrorist appears out of nowhere, methodically thumbing the buttons of his cellphone to trigger the bomb before Sergeant Thompson can get clear of the blast area. You sense, as this threat suddenly appears from the side of the sound stage, how even a moment’s hesitation can prove deadly. Specialist Eldridge shouts out one last warning when ordered to shoot the terrorist, and that split-second of hesitation costs Sergeant Thompson his life. The Definitive’s also do a good job of handling the bomb blast itself, which can potentially overload some systems. The punchiness and control of the Definitive woofer system really helps here.

The scene, like several others in this powerful film, is designed to use sonic cues to highlight the dramatic difference between life as experienced within the sweltering heat and relative isolation (and even serenity) of the bombproof suit vs. the swirling cacophony and imminent danger without. Ideally, the soundtrack presents tons of small yet significant upper midrange and treble details (or the pointed absence thereof) to dramatize and contrast the world of the suit vs. the world of the lawless streets of Baghdad. But the Definitives tend to underplay those details to some degree, suppressing some of the gripping immediacy of the soundtrack as a result. So, the Definitive gets high marks for dynamic punch and composure, and very high marks for spatial presentation, yet comes up just a bit short in terms of retrieving very low-level details that add emotional and sonic vividness to soundtracks such as this one.


To assess the system’s musical I chops I turned to two of my favorite multichannel reference recordings, first the Marriner/Academy of St. Martin in the Fields recording of Orchestral Works by Gordon Getty (Pentatone Classics, multichannel SACD) and then jazz-inflected First Impressions from Blue Chamber Quartet (Stockfisch, multichannel SACD).

On the Getty recording, I focused in particular on the roughly 12-minute long Overture: “Plump Jack”, which provides a compact sampler of orchestral moods and voices. What caught my ear was the ease with which the BP-8040ST system precisely positioned individual orchestral sections in believable locations on the stage, while at the same time conveying a larger sense of the whole orchestra and of the volume and acoustics of the recording venue. Low percussion sounded appropriately powerful and full of impact, while brass (and especially low brass) had a beautiful and sumptuous burnished glow. Strings, in turn, had appropriate warmth with just a hint, in the case of high strings, of incisive edges (but not unpleasantly incisive edges, thanks to the smoothness of the Definitive tweeters). But the main overarching impression left by the system was one of appropriate scale; when big orchestral moments came along, the system seemed to draw a deep breath and to expand to meet the requirements of the musical situation—something not many systems in this size or price range could do so convincingly.

On First Impressions, I found myself draw, as is often the case, to the quartet’s interpretations of small-scale works by the composer Astor Piazolla. In particular, I was drawn to Blue Chamber Quartet’s rendition of the delicate piece “Tanti Anni Prima”. On this piece, the four instruments that comprise the quartet are beautifully showcased, so that you have time to savor the upper register playing of bassist Holger Michalski, the ringing and downright tubular voice of Thomas Schindl’s vibraphones, the wide-ranging sonorities and lilt of Angelika Siman’s harp, and the vigorous yet never overpowering sound of Julia Bartha’s piano. But frankly, many speakers do a good job with the tonalities of the instruments on the carefully made recording. What made playback through the BP-8040ST system special, was the truly exceptional manner in which it captured (and I mean vividly captured) the placement of the instruments within the soundstage. On some systems, the four instruments can sound a bit “crowded together,” but through the Definitive system the size and scope of the soundstage became more fully apparent, so that I could hear each instrument occupying a distinct piece of “real estate” within the larger stage. This not only gave a heightened sense of realism, but helped to convey a sense of place—reminding the listener that in really good recordings the sound of the instruments become, in a very desirable way, intertwined with the sound of the room in which the performance unfolds. This sense of place is something the Definitive system gives you in spades, which is pretty remarkable in light of its modest size and price.

Finally, as a bit of an over-the-top exercise, I put on one of the new Naxos audio-centric Blu-ray (24-bit/96 kHz) recordings, this one the Wit/Warsaw Philharmonic Choir and Orchestra performance of Gustav Mahler’s Symphony No. 8 (the famous ‘Symphony of a Thousand’). Candidly, the sheer scale of this piece—and especially the scale of its concluding minutes—is so large and demanding that I’m not convinced that any music playback system can fully do it justice, let alone one selling for a tick under $2600. Nevertheless, the BP-8040ST system gave the symphony one heck of a college try, and in the process it won my admiration for maintain its composure in the face of towering sonic demands. While I won’t tell you the system sounded completely realistic during the concluding minutes of the symphony, which would be a stretch even for five-figure or six-figure systems, it did a great many things right. In particular, it did an astonishingly good job of delineating individual vocal lines and passages from individual chorus sections, while keeping all of the orchestral action more or less straight (something that, on the very demanding piece, is much easier said than done). Specifically, the Definitive system sound focused and appropriate ethereal (even mystical) on the haunting passage highlighting the lyric “Blicket auf zum Retterblick, alle rueig Zarten.” What was revealing, I felt, was that the system not only achieves definition in the usual ways, via textures and timbres, but also achieves definition through careful emphasis of stage position. There is no tendency with this system, as there sometimes can be with other systems, for the soundstage to become an ill defined, homogenized mish-mash of voices. Instead, performers and choir/orchestral sections stay put, and are appropriate spread out upon the canvas of a big, broad stage that perfectly complements the scale of the composition.


Consider this system if:

•You want a well-priced system that offers a hearty, full-bodied sound with potent dynamics, and that produces huge soundstages with well-focused images of performers (or sound effects) upon that stage.
•Consider this system, too, if you prize speakers that offer natural and almost “organic” warmth (as over and against strict textbook accuracy).
•Finally, note that this particular system strikes many that see it as being an almost perfect size—big enough to handle large living rooms, yet compact enough not to register as being bulky or visually overbearing.

Look further if:

•You are a true, strict-interpretation accuracy maven or are seeking the highest levels of detail and transparency possible (in which case you may want to save up for Definitive’s excellent, but also more costly, Mythos ST or STS systems).
•But be careful what you ask for, since few speaker systems in this price range can match this Definitive rig’s expansive soundstaging capabilities.

Ratings (relative to comparably-priced surround speaker systems)

Transparency and Focus: 8.5
Imaging and Soundstaging: 10
Tonal Balance: 8.5
Dynamics: 9
Bass Extension: 10
Bass Pitch Definition: 9.5
Bass Dynamics: 9.5
Value: 9.5


The BP-8040ST offers an immediately likable and accessible sound with great natural warmth, expansive soundstaging, well-focused imaging, and really impressive bass output.


Definitive BP-8040ST 3-way, six-driver bipolar floorstanding speaker
Driver complement: Two 1-inch aluminum dome tweeters, three 3.5-inch BDSS mid/bass drivers, one 8-inch bass driver, and two 8-inch passive radiators.
Frequency response: 25Hz – 30 kHz
Sensitivity: 92 dB
Impedance: 8 ohms
Dimensions (HxWxD): 39” x 5.625” x 11.625” (main speaker without stabilizer feet installed)
Weight: 40 lbs. each
Warranty: Speaker components 5 years parts and labor, active electronic components 3 years parts and labor
Price: $1498/pair

Definitive CS-8040HD 2-way, three-driver, center-channel speaker
Driver complement: One 1-inch aluminum dome tweeter, two 4.5-inch BDSS mid/bass drivers, one 5-inch x 10-inch passive radiator
Frequency response: 40Hz – 30 kHz
Sensitivity: 92 dB
Impedance: 8 ohms
Dimensions (HxWxD): 5.75” x 21.125” x 12”
Weight: 20 lbs. each
Warranty: 5 years, parts and labor
Price: $499 each

Definitive SR-804BP 2-way, four-driver, bipolar surround speaker
Driver complement: Two 1-inch aluminum dome tweeters, two 3.5-inch mid/bass driver
Frequency response: 50Hz – 30 kHz
Sensitivity: 92 dB
Impedance: 8 ohms
Dimensions (HxWxD): 9.5” x 7.812” x 5.375”
Weight: 8 lbs. each
Warranty: 5 years, parts and labor
Price: $498/pair

System Price: $2595 as tested

Definitive Technology
(800) 228-7148

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