To be perfectly candid, until recently I hadn’t really given Definitive Technology speakers much consideration, primarily because I have not been in the market for a pair of speakers retailing for under $2000, but also because the only place I had seen them had been at CEDIA, where they blended in with dozens of other speakers on the trade show floor. That changed a couple of months ago when I set out to document to state of two channel audio in my hometown. If you are interested in the results of my research project, you can read them here.
While on my little adventure, I saw Def Tech speakers on display at the one remaining hi-fi shop in Nashville, decided to give several models a listen, and thought they might make a good choice for a full-range speaker at the entry-level. So I got in touch with Paul DiComo, Senior Vice President of Marketing and Product Development at Definitive Technology, and in no time at all, a pair of BP-8060STs ($1998/pair), which Paul describes as being at the sweet-spot in the line, arrived at my door. Actually, they arrived in a freight truck at the end of my driveway for curbside delivery. At nearly 100 pounds each, I wasn’t about to schlep them 200 feet to my front door, so I backed my station wagon down the driveway and cajoled the freight delivery guy into helping me load them in for the ride up to the house. After a quick trip to Home Depot for a hand truck, I had them in my secondary listening room in no time.
Unboxing them took a while longer. They are very well packed in double boxes with foam supports protecting them from the inevitable bumps and bruises of transit. Mine were in flawless condition. Once I got the outrigger-style support and leveling brackets screwed on, I flipped them right-side up, walked them into position, and sat down and had a look. I was kind of scratching my head about all the effort required to get these tall and svelte loudspeakers set up for listening. I mean really; they are only 6” wide. If you toe them in, they practically disappear. No diffraction worries here. They are nearly 14” deep and a bit over 44” tall, with the tweeter at 37” – just about ear level for me. Except for a glossy black top plate they are covered entirely in a black fabric sock like many of the Vandersteen speakers. They are quite elegant looking and met with quick spouse approval.
As you can see from the transparent view of the speaker above, the Def Tech BP-8060STs are of quite complex design. I think they are best described as bipolar mini-monitors on dedicated stands with built-in powered subwoofers. Let’s address the mini-monitor aspect first. On the top front are two 4.25” midrange drivers and a 1” aluminum dome tweeter arranged in a vertical D’Appolito configuration. No other speakers are placed on the front panel. At the top rear are an identical 4.25” midrange driver and 1” tweeter. A bipolar arrangement poses special challenges and benefits as we will see in a moment. At the bottom on one side is a 10” high-excursion subwoofer powered by a 300 watt Class D amplifier, underneath which is a 10” passive radiator. A companion 10” passive radiator sits opposite it on the other side. No indication is given as to whether the powered subwoofer should be facing outward or inward. In my setup, I had them facing outward. The rear panel has the usual five-way binding posts, as well as an IEC inlet, volume control and indicator lamp for the powered subwoofer. One clear advantage to the powered subwoofer arrangement is that the mini-monitor section, which has a sensitivity of 92db, can easily be powered by an integrated amplifier, even a low-powered tube model.
I first set up the BP-8060STs in an equilateral triangle with my listening position. I gradually moved them closer together, then farther apart, to attempt to simultaneously achieve both a strong central image and a wide soundstage. I ultimately ended up with them slightly closer together than the distance to the listening position. I also found that a moderate amount of toe-in really anchored the center image. In addition, I pulled them slightly closer to the listening position than I normally do to increase the depth of the soundstage, and to lengthen the arrival time of the front wall reflections from the rear mounted speaker drivers. This arrangement gave a spacious soundstage extending well beyond the bounds of the speakers.
As a side note, I purposely left the front wall of my listening room untreated, other than bass traps in the corners, knowing that I would be auditioning bipolar loudspeakers like the BP-8060STs, as well as planar-magnetic and electrostatic designs. As shown in this sketch from Art Noxon’s white paper on ASC TubeTraps, which can be referenced here, high frequencies are disbursed in a cardiod pattern, meaning that reflections from the wall behind a front-firing tweeter are not typically a problem.
The wall behind speakers is usually treated with diffusion to address reflections from the wall behind the listening position. In my case, the wall behind my listening position is heavily treated with absorption panels to prevent the slap echo so prevalent in small rooms. Adding diffusion to my front wall might have a slight beneficial effect, but those benefits are outweighed by the detrimental effects it would have when listening to bipolar loudspeakers.
Having positioned the speakers optimally, it was now time to address the subwoofers. Actually, they are not subwoofers in the traditional sense. There are no adjustments for crossover point or phase. The crossover point has been optimized for the mini-monitor section of the speaker, and because the low frequencies emanate from the same distance to the listening position as the mid and high frequencies, no phase adjustment is necessary. So what you are left with is simply adjusting the volume of the bass. This is a blessing as well as a curse. The blessings are three-fold: first, being able to adjust overall bass volume to accommodate boundary reinforcement (or lack thereof); second, being able to adjust bass volume for each speaker individually to accommodate an asymmetrical speaker arrangement with differing boundary bass reinforcement; and third, being able to adjust bass to preference. The curse is that, unless you just want to leave the bass level at “normal” by setting the volume control at the 12 o’clock position, you are in for a long and arduous process of fine tuning, and, without room measurement software, at the end of the day you are just guessing at the optimal level. But that’s no different than with any subwoofer, so no negative marks are awarded.
I initially tried to set the bass volume by ear, which was, in essence, frustrating folly. What sounded good on one recording sounded either weak or overblown on another. In addition, the volume control is continuously variable, so there is no going back to exactly where you were before you made an adjustment. The way I overcame that problem was to put strips of painter’s tape behind the volume control with a series of markings from 8 o’clock to 4 o’clock so I could have relatively close repeatable settings. I have discussed this issue with Paul DiComo, and he is looking into incorporating a stepped volume control in the future. I didn’t want to have to adjust bass volume on a disc-by-disc basis so, being somewhat obsessive, particularly in the context of a review, I finally simply ordered a calibrated Behringer ECM8000 measurement microphone and downloaded Room EQ Wizard (REW) software here.
I plugged the ECM8000 into my trusty Digidesign MBox2 microphone preamplifier, then into the input of my laptop to record the frequency response of the speakers. I also ran a USB cable from my laptop to the USB input of the Benchmark DAC1 HDR to playback the test tones from REW. With those tools in hand, I was able to set the subwoofer level on each BP-8060ST independently, and then together, to achieve as flat a low frequency response as possible for my room. After listening to several discs, I thought the speakers sounded a little lean, so I bumped up the bass somewhat.
Since the BP-8060STs throw such a spacious soundstage, I thought I would start of with a recording from a large venue – Anonymous 4 performing Hildegard von Bingen’s 11,000 Virgins – Chants for the Feast of St. Ursula on Harmonia Mundi. It was recorded in 1996 in the Holy Spirit Chapel at the Jesuit-sponsored Campion Center in Weston, Massachusetts (shown below). There are 18 chants divided into three sections: Vigil, Lauds and Vespers. The purity and clarity of the four women’s voices was striking, as was the enormous ambiance retrieval. In my small listening room, the effect was virtually surround sound. This is late night listening music at its finest. Unless you are fluent in Latin, you won’t have a clue what they are singing, so the religious aspects of the recording are a bit beside the point. You will simply be awash in harmony and polyphony. It has the most wonderful calming effect.
As I mentioned in a previous review, Bach’s Cello Suites are among my favorite classical compositions. One version I have has been transposed by Edgar Meyer for double bass, the effect of which is to reduce the lowest note played from the open C of a cello (65Hz) to the open E of the double bass (41Hz). The transposition gives the Cello Suites a distinctly lugubrious feeling, which is accentuated by Edgar’s slower tempos. The BP-8060STs reproduced the low-end without strain and in a fulsome manner, and at the same time, the sound of the bow on the string is crisp and distinct. There is no muddying of the tones. By using a sealed box approach with passive radiators instead of a ported design, any possibility of honking is eliminated. The BP-8060STs will, of course, go much lower that 41Hz, with a specified low frequency response of 20Hz. As quick spin of Daniel Chorzempla playing various Bach organ works confirmed that the speakers will plumb the depths. I did not play Saint-Saen’s Organ Symphony, however, to put them to the ultimate 16Hz test.
The violin is a tough test for the upper midrange and treble for, among other reasons, its fundamental frequency response (approximately 200Hz to 4200Hz) transcends at least one and often two crossover points, as is the case with the BP-8060STs. Reproducing the violin coherently is no small challenge for a speaker designer. Time for a trip to the turntable to listen to Tchaikovsky’s Violin Concerto played by Eugene Fodor in concert with the New Philharmonia Orchestra led by Erich Leinsdorf. Fodor, who studied under Jascha Heifetz, won the International Paganini Competion in 1972, the first American to do so in over 20 years. No doubt his recording contract with RCA was a direct result of that accomplishment.
The first movement of the Tchaikovsky violin concerto starts softly, building to a crescendo, and after a brief transition, the violin enters with a lyric passage. The dynamics of such an opening were well handled. I would describe the violin tone as sweet, but entirely natural. Low notes resonate and high notes exhibit no etched quality, indicating a smooth transition from midrange to tweeter, with no intentional emphasis on “detail.” The orchestra is assertive between violin solos, but pizzicato strings passages are not lost in the mix, and woodwinds are distinct and well reproduced. Overall, the recording, and its presentation by the BP-8060STs, was balanced and engaging.
The Definitive Technology BP-8060STs, and the other models in Bipolar and Bipolar SuperTower series, are, to my knowledge, unique in incorporating a bipolar speaker design with a powered subwoofer. Although requiring painstaking effort to set up optimally, you will be rewarded with a remarkably wide and deep soundstage and a bottom-end which reproduces the lowest octave of recorded music, all in a tall, slim and elegant enclosure coming in at under $2000. It is quite an achievement. The speakers are relatively neutral, if a bit on the lean side, so if you prefer a warmer sound, you might consider pairing them with a tube amp. The BP-8060STs are a must audition for the music lover. I think you will be both as surprised and impressed as I was.
- Frank Berryman
Analog Source: VPI Scout; Dynavector 20X2; Musical Surroundings Phonomena II
Digital Source: Windows 7 music server with ESI Juli@ soundcard, Arcam FMJ CD17
Preamplifier: Meridian G68ADV; Benchmark DAC1 HDR
Power Amplifier: Meridian 557; Arcam FMJ A18
Loudspeakers: Meridian DSP5500
Cables: Digital: Meridian; Analog and Speaker: Audience Conductor “e”; Power: Volex/Marinco
Headphones: Etymotic ER-4S
Accessories: GIK acoustic treatments; dedicated 20 amp circuit