Definitive Technology BP-8040ST SuperTower Speakers

Introduction to the Definitive Technology BP-8040ST SuperTower Speakers

Pssst….want to hear a really cool speaker, but you have to keep it a secret. The voice was familiar but I looked around for the white van, none to be seen. Sure, but they’d better not have fallen out of the back of a truck I replied. Nah he said just come up to my private room in this hotel. Up the exterior stairs we went to his suite, nice. Now I want to show you what’s in this other room behind this curtain. Hmmmm

Well maybe it didn’t quite go like that, and Paul DiComo, the SVP of Marketing and Product Development at Definitive Technology is one of the good guys in this business, but I was intrigued when he invited me to hear an early prototype of the complete-from-the-ground-up bi-polar tower floor speaker. Bi-polar speakers have been the legacy at Definitive Technology since the early days in the 1990’s.

Immediate impressions told me he had something interesting happening as we heard one track after another. We chatted about where the image was coming from and how impressive the bass was. He said I’m really excited about this product and we should be in production soon. About a year later, a pair of stocking-clad speakers arrived from Def Tech.

Typically when there are a variety of sizes available as there are in the bipolar line, I usually ask for the big ones! When I asked Paul what he wanted to send, he said instead of just sending the largest, let me send you the smaller, third from the top in size, the BP-8040T because, well, wow, you just have to hear them!

So the nomenclature should be simple enough; “BP” is Bi-Polar of course and “ST” for Super Tower! Definitive Technology with Paul’s lead developed the 8000 Series to include four sizes from the smallest BP-8020ST through the 8040, 8060 and the 8080. Each by the way has an available corresponding center channel and surround speaker.

So here’s where I need to take a step backwards…

When Definitive Technology sent me a pair of thin Mythos XTR-50’s I wasn’t able to review them in a timely manner but let me include some information about them, and trust me this is going somewhere.

Super thin (or should I say super flat?) and very cool the XTR line comes in 3 lengths as needed for your panel size. The 50’s at 27″ high perfectly matched my 47″ LCD panel. With flat panel TV’s becoming ever thinner and thinner, the bulky on-wall speakers available diminished the sleek styling. Definitive’s response was this amazing 1 ½” deep speaker with an array of drivers.

The unit is beautifully machined and compliments the design of any flat panel elegantly. Its face is slightly curved further exuding the slick style and thin profile. Naturally it was specifically designed acoustically and stylistically to be mounted on the wall next to your TV (wall mounting yields a bass response down to 92 Hz), yet it comes with a smoky glass stand in case you have your TV stand mounted instead.

Two aluminum dome 3.5″ mid-bass drivers coupled with four passive radiators flank a 1″ pure aluminum dome tweeter, the same one found in the Mythos STS Super Towers.

The XTR-50’s yielded an exceptional and balanced sound. So much so that it began a discussion about developing a new bipolar design. Definitive Technology literally took a pair of XTR-50’s and placed them back-to-back. Using a professional mixing board, Definitive’s engineers varied the output of the front to rear speakers to establish the best balance, off axis image and large image size sought for bi-polar designs overcome two issues common with bipolar design, clarity and focus.

The engineers discovered that by varying the output from front to rear, they came up with a formula of a 10 ms delay, or 5 feet from any near wall surface. Secondly varying from traditional bi-poplar design, Def Tech reduced the energy output from the rear speakers by +/-6 dB. This not only enhanced the spacious feeling but also the potential for residual sound.

Hence the true benefits of bipolar design; it will fill your room with sound, ever-increasing the soundstage, or the proverbial “wall of sound”. Whereas front-firing speakers no matter what you do or how you set them up, will tend to “funnel” sound in the mid and higher frequencies narrowing the sweet spot.


  • Design: 2-way Hybrid Tower Speaker
  • Drivers: Two 1″ Aluminum Dome Tweeters, Two 3.5″ Midrange, One 8″ Powered Woofer with Two 8″ Passive Radiators
  • MFR: 25 Hz – 30 kHz
  • Sensitivity: 92 dB
  • Nominal Impedance: 8 Ohms
  • Recommended Amplifier Power: 20 – 300 Watts
  • Internal Amplifier Power for Woofer: 300 Watts
  • Inputs: One pair of 5-way Binding Posts; One LFE Input (optional)
  • Dimensions: 39″ H x 5.6″ W x 11.6″ D
  • Weight: 40 Pounds/each
  • MSRP: $799/each USD
  • Definitive Technology
  • Secrets Tags: Tower Speakers

Design of the Definitive Technology BP-8040ST SuperTower Speakers

The overall design is typical Definitive, understated; it’s literally covered head to toe with a black fabric and pulled tight at the top under a molded gloss black cap. The 8040 is modest in size at about 39″ tall. Because the speaker is unlike me and rather narrow, Def Tech incorporates speaker legs that look like out riggers to keep them from tilting over and can be fitted with either carpet spikes or rubber feed.

The rear shares similar design and layout with the Mythos STS; sturdy speaker connections, a line level LFE input with subwoofer volume control, and a detachable power cable.


So what else, and why that giant sock?! Well, if you have a speaker that has drivers on all four sides, it may be a little distracting and probably expensive to build the finished enclosure I suppose and invest the cost on performance. Frankly, I like the design, it’s totally non-assuming.

Although narrow, its depth is sized to hold side-firing sub-woofers by using the wider depth of the speaker, Def Tech places a 300 watt Class D amplified side-firing subwoofer. In addition to the 8″ active driver, 2 passive radiators are placed, one on each side.

When I realized that the each speaker is identical, that is the powered woofer is on the left on both speakers, I wondered why if the intent was to create more ambient sound, why not place them both firing out, using perhaps the side walls? Paul’s answer, well for simplicity – why make setup even harder for the average consumer.

Similarities to the Mythos Series are a plenty, besides powered subwoofers, they share the same woofer and tweeter drivers. The same 1″ pure aluminum dome tweeter in the BP-8040ST’s can be found in the Mythos.

The BP-8040T has 2 front firing (and 1 rear facing) 3 ½” mid-range drivers arranged above and below 1″ tweeter. The drivers are the same found in the Mythos towers. Cast iron baskets used are more rigid and eliminate any interference with the magnetic coil which hopefully reduces distortion and plays cleaner. The mid-range drivers have molded butyl rubber surrounds for longevity and mineral filled polymer cones for natural sound, all especially for voices.

Front without sock

Rear without sock.

Def Tech uses their patent Balanced Double Surround System (BDSS) driver design. The critical part is the cone is supported on both the inner and outer edges. Def Tech designed it to have a longer excursion thereby improving output.

A frequency multi-band digital signal processor (DSP) constantly adjusts the cross-over while monitoring woofer overload and applying compression to prevent distortion.

Care went into the layout of the internal structure. The mid-range drivers are isolated with their own MDF enclosures. This is not new or unusual but Def Tech employed a system of proportions to the volumes. From my architectural background I’m familiar with the principals of golden mean. Used in the Renaissance because it represents the most “pleasant” proportions found over and over in nature golden mean, or rather golden ratio is the relationship of larger to the smaller. The idea that from a perfect square we can mathematically develop a length to width ratio, specifically 1:1.6. (Ever wonder why we find a 16:9 screen more appealing than a 4:3?)

Def Tech further uses Fibonacci mathematical principles of order. Taken the sequence of numbers adding one to the next highest; 0 +1 =1, 1+1=2, 1+2=3, 2+3=5, 3+5=8, and so on, a spiral is created using the resulting numbers, 1,1,2,3,5,13,21, etc. That resulting geometric enclosures might be considered the most important aesthetic principal of proportions.

What does all that mean to sound? By adjusting the volume of the driver enclosures by the size of the driver, in theory the sound should be balanced. Def Tech engineers believe these volumes perfectly proportioned reduce unwanted resonance and vibrations.

Setup of the Definitive Technology BP-8040ST SuperTower Speakers

In the two-channel setup, equipment used included a Rogue Audio Athena tube-preamp fed through a Parasound amplifier and sourced with a Marantz turntable and SACD player, speaker and interconnect cables from Transparent Audio.

So the nature of these bipolar is flexibility. Speakers in general will suffer if not placed specifically the right distance from the rear and side walls effectively sucking breath from a narrowed soundstage, or create blurred definition if not properly toed. Not the BP-8040ST’s, moving them around doesn’t change the sound for better or for worse, it’s simply different.

A smaller room with the speakers placed closer to the rear or side wall will heighten both bass and the low midrange. Likewise, if the room is larger or space is ample, the speaker floating away from near walls gives the speaker a bit more lightness, slight more clarity if not downright sweeter. These are not traits on any speaker; the BP-8040ST’s will adjust to your space nicely. A quick turn of a few degrees on the rear bass gain and the bottom end fills in “to taste”.

Placement hardly alters those traits of sound space. In fact I spent most of my time reviewing the speakers about 6 feet apart before Paul suggested placing them further apart and toed in significantly. What was the difference? Well, breadth and space remained but the near, rear and side walls, entered into play. What about soundstage, instrument and voice presence? Well here is where the BP is forgiving, in the best possible way.

Definitive Technology BP-8040ST SuperTower Speakers In Use

My experience with the BP-8040ST’s has been extremely positive and I begin by saying I’ve had many “ah ha!” moments. Expect a smooth, rich and detailed presentation from the 8040’s. Since having the Mythos STS in my system for awhile now, I’m familiar with the drivers employed. I’m not surprised in the least from what I heard.

My first listening was using the BP-8040ST as left/right mains in a theater setup. I ran the system as 2-channel first and setting the speakers as full allowing the built-in powered subs handle the low end. My room isn’t large at about 12 ft by 16 ft, but wow, the bass rocked the house like I had a pair of outboard independent subwoofers. The rear output adjustment allowed a very balanced presentation, both for movies and music on Blu-Ray of which I’ve become a huge fan.

Sting’s Live in Berlin is more than his “hits” but also a wonderful collaboration with the Royal Philharmonic Concert Orchestra. You do have to be a Sting fan to appreciate the music however, the full breath of a live orchestra is enchanting especially with Jo Lawry singing subtle but superb backup. The pair of 8040’s alone performed remarkably given this is a DTS-HD Master meant to be heard in full surround. I truly appreciated the depth and fullness of the stage.

Many of the tracks were in full orchestra mode, but I appreciated the superb individual performances from the likes of Branford Marsalis. On several tracks, his saxophone was elegant, earthy and throaty.

For those who say opera is irrelevant today, watch and listen to any of the stunning Blu-rays from Opus Arte. Mozart’s Cosi Fan Tutti performed by the Orchestra of the Age of Enlightenment with The Glyndebourne Chorus and conducted by Ivan Fischer is beyond visually stunning. Broadcast live on the BBC, the performers amply expressed through the 8040’s by allowing the weaving of female and male voices across the stage, yet the clarity of each voice distinguishable. I’m actually surprised by the distinct warm tones of each performer rendered by the Def Tech bi-polars.

Balanced, that’s a good word for the 8040’s. Although the 8040’s are full range, punchy and dynamic, I very much like the aluminum dome tweeter; the treble is clean and natural smoothness. Having said that, I wasn’t expecting razor-edged definition and not that I wanted it. Yet what I did hear was not bright and brittle, but rather mellow and listenable for hours.

Monster is well known for their cable line but Noel Lee is a big music fan, especially of well engineered music. Their “High Definition” MonsterMusic recordings are actually excellent. Although limited in musical range, I have several of the discs. George Benson and Al Jarreau present a wonderful duet on giving it up. Listening to this recording is like a hot cup of cocoa: familiar, warm and puts a smile on your face. Each track is a new interpretation of original music and not all from Benson or Jarreau. Perhaps this recording is too “smooth jazz” for purists but the 8040’s make you sit back and enjoy all the nuisances present, with the ease of the voices and instruments in a perfect blend.

And finally, a few words about bass, the 8040’s deliver oodles of it and at whatever volumes you’d like. I found myself over time turning it down via the rear bass volume control ever so slightly and settling for about 1/3 the potential output for my modest-sized room.

The bi-polar Def Tech’s delineated a range from deep rich low bass to full mid-bass up to articulated upper bass/lower midrange. Pipes Rhode Island is a series of recordings taken around the state at various churches and their pipe organs. The tracks range from sweet and delicate to powerful and bold. The 8040’s render the expressive organs in their natural and spatial settings. The echoes and resonance of the churches have you looking up to the rafters. The sub 20Hz tones fill your gut like 2 pounds of spaghetti.

Conclusions About the Definitive Technology BP-8040ST SuperTower Speakers

The BP-8040ST’s performance far exceeds their more than reasonable price, and will be my strong nomination for recognition in our annual awards program. Although the size is modest for a floorstanding speaker, it certainly is a full-range speaker, indeed. The BP-8040ST hit the mark that make a speaker special; tone, speed, dynamics, and balance.

Placement was forgiving and amplifier power needed to get the most of these speakers was minimal, making these an ideal choice for even a modest receiver.

I’d have followed you anywhere to hear these speakers Paul, bravo for a great project.