Definitive Technology Demand D15 Tower Speaker Review
- Product Name: Demand D15 Tower Speaker
- Manufacturer: Definitive Technology
- Performance Rating:
- Value Rating:
- Review Date: July 13, 2020 07:00
- MSRP: $ 3,398/pr
- Type: 3-way Tower Speaker
- Tweeter: 1" (2.54 cm) d (Round) Annealed Aluminum Dome and Laterally Offset
- Midrange: 5.25" (13.34 cm) d (Round) Polypropylene BDSS Bass - Midrange
- Woofer: (2) 5.25" (13.34 cm) d (Round) Carbon Fiber woofer - Mid/Woofer
- Passive Radiator: (2) 8" (20.32 cm) d (Round)
- Frequency Response: 39 Hz → 24,000 Hz
- Nominal Impedance: 8 ohms
- Sensitivity (1 watt @ 1 meter): 85.5 dB
- Lower and Upper -3dB Limits: 48 Hz → 22,000 Hz
- Peak Power Handling: 300 watts
- Tweeter/Midrange Crossover Frequency: 2500 Hz
- Midrange/Bass Driver Crossover Frequency: 450 Hz
- Weight: 52 lbs (23.59 kg)
- Dimensions (HxWxD): 40.78" (103.58 cm) x 9.05" (22.99 cm) x 12.86" (32.66 cm)
- Available finishes: Gloss Black, Gloss White
- Warranty: 5 years
Pros
- Very neutral on-axis response
- Excellent imaging ability
- Very good build quality
- Good dynamic range
- Extremely good industrial design
Cons
- Average low-frequency extension of 39 Hz
- Relatively insensitive for floor-standing speaker
Definitive Technology launched their ‘Demand’ series loudspeakers
back in late 2017 with three different bookshelf speakers. Two and a half years
later they have finally expanded their Demand series line with two
floor-standing speakers and a center speaker with the D15, D17, and D5C
respectively. The difference between the two floor-standing speakers is that
the D17 uses slightly larger drivers which should give it a bit more bass
extension and slightly more dynamic range. In for review today, we have the D15.
The Demand towers are unusual in that they occupy a similar price range as
other floor-standing speakers from Definitive Technology, namely the BP-9000
series. It is not often that loudspeaker manufacturers have lines similarly
priced in the same company.
There are two key differences between the BP-9000 and Demand product lines. One difference is that the BP-9000 series use a bipolar design where sound is projected from the rear of the loudspeaker. This should make for a sound infused with more late reflections which have been shown to increase listener envelopment, although that may come at the cost of a wide soundstage and precise stereo imaging. Another difference is that the BP-9000 series uses built-in powered subwoofers. That takes a load off of the user-provided amplifier. However, with the prevalence and flexibility of powerful and affordable subwoofers, built-in powered subwoofers are more of an appeal to those who do not want to devote floor space to stand-alone subs.
In comparison, the Demand series is a much more conventional loudspeaker design. The exclusion of rear speakers may make for a more acoustically predictable speaker with finer imaging and a wider front soundstage. The absence of a powered subwoofer section makes integration with outboard subs less complicated. So while Definitive Technology has two different lines occupying a similar price range, in my opinion, they are different enough to justify their availability. Definitive Technology seemed to want to offer a more conventional alternative to their BP-9000 series, hence the reason for the creation of the Demand tower speakers.
Let’s focus on the Demand D15 itself for a moment. At $3,400 a pair, they certainly are not cheap but nor are they extravagantly expensive either. It’s a simpler loudspeaker design than Definitive Technology’s other floor-standing speakers, and if this simplicity is an exchange of complexity for higher quality, that can be a welcome trade. This is not to say that the design is simple, and we will get into the various aspects of its construction in our ‘design analysis’ section, but it is a lot more of a traditional loudspeaker than the BP-9000s. There are a lot of traditional floor-standing loudspeakers in its price range, however, so what does the Demand D15 do to separate itself from the rest? Let’s find out…
Appearance
Upon arrival, the D15 speakers do need a slight amount of assembly by screwing in a metal plinth to the bottom and screwing feet into the plinth, but that is easy and takes less than 5 minutes. Following directions on the box, this should be done before unpacking the speakers. Unboxing the D15’s reveals them to be a strikingly modern design. The boxiness of the cabinet is not at all softened by corner rounding, and, in fact, the design embraces it with hard right angles at all corners. This is an effort to contrast the many circles of the drivers that are emphasized with black cones against the light aluminum front baffle. The all-aluminum front baffle provides a very attractive and high-end element to the appearance, and, to be honest, I am surprised to find something like that in a speaker at a price this low. While the industrial design here is striking, I don’t think it is ‘loud’ in that it will become the center of attention in most rooms. For those who want a tamer appearance, the grille hides the front baffle with a light-silver fabric and gives the speaker a much more minimalist look. The grille uses magnetic adhesion, so it has no grille guides to interrupt the smooth appearance of the front baffle. With the gloss white finish (a gloss black finish can also be had), the grille’d D15 is so minimal that it looks almost like a piece of abstract art. Normally, I think grilles make the speakers just look dull, but that is not the case here. Strangely, there are few images of the D15’s with the grille on posted to Definitive Technology’s product page.
There are 8” passive radiators on both sides of the speaker that have a gloss white cone and are easily the nicest-looking passive radiators I have ever seen. The tweeter is an aluminum dome that is partly obscured by a phase lens and has a mirror-image offset in a large black faceplate. It almost resembles an eye that is looking off to the side. The midrange driver has a large phase plug that Definitive Technology has used in past designs. I have never cared for the way it looks in the past, but somehow it isn’t as visually obtrusive here. The bass drivers have a sleek-looking carbon fiber cone. Altogether, I think it's an interesting looking speaker with or without the grille. I am guessing that even people who normally object to the appearance of speakers will get along with these when the grille is in place. In the Gloss White finish, they would fit right in any brightly colored decor. All-in-all, the Demand D15 speakers look quite nice.
Design Analysis
The Definitive Technology Demand D15 loudspeakers are a three-way floor-standing design that uses passive radiators to augment low frequencies. In such broad strokes, that isn’t a particularly unusual design, but there are a host of design innovations that do set the D15s apart from other tower speakers in its class.
Let’s begin our discussion starting from the top and going down, so let’s talk about the tweeters. The D15 tweeters use a 1” aluminum dome mounted in a shallow waveguide. The aluminum of the tweeter dome is annealed, which means it has been softened by bringing the aluminum close to its melting point and then allowing it to cool slowly. This process dissolves the crystalline structure of the metal, and, in its recrystallization, it becomes softer. In its softer state, it has increased the damping which can tame break-up modes in higher frequencies. It should make for a smoother sound, especially with those people who are sensitive to higher treble frequencies. There is a plastic piece with partly covers the front of the tweeter that is a phase lens that Definitive technology calls the ‘20/20 Wave Alignment Lens.’ Its purpose is to block sound from the tip of the tweeter dome from interfering with sound emanating from the sides. It could also serve as protection for the fragile diaphragm of the tweeter dome.
The midrange driver is a 5.25” polypropylene design that is quite unique to Definitive Technology that they call the ‘BDSS Woofer,’ which stands for ‘Balanced Double Surround System.’ It gets that name because the cone uses two surrounds: one surround on the outer edge of the cone and one in the inner edge that attaches it to the phase plug. Definitive Technology claims that this double surround system allows greater linear excursion. In theory, it should be possible that two surrounds could provide a more controlled excursion from the suspension components, although I can’t imagine that would provide a huge increase in excursion. This particular midrange phase plug is also something only seen in Definitive Technology loudspeakers, and they call it the ‘Linear Response Waveguide.’ It’s the largest phase plug I have seen, and that is probably why Definitive Technology calls it a waveguide, although it certainly does not function as a traditional waveguide. It looks to me like it just does what normal phase plugs do which is blocking wavefronts from the different areas of the cone from colliding and interfering with each other. It just does it a lot more than normal phase plugs.
For the bass drivers, the D15 uses two 5.25” carbon-fiber cones.
They look nice and have a beefy surround and so they should be quite capable in
bass frequencies. They are also used to power the two 8” passive radiators on
the side of the speaker. Definitive Technology claims a lower -3dB limit of 48
Hz for the D15, so these radiators should be very competent down to 50 Hz at
least. I wasn’t able to get a close look at the bare
drivers since a trim ring covers the frame screws, and removing the trim ring can
be a bit risky since it is glued on.
The crossover circuit is a pretty formidable piece that uses a multitude of higher-quality components such as metal-film capacitors and air-core inductors. There is a second-order acoustical crossover between the bass driver and midrange driver at 450 Hz and a third-order crossover between the midrange and tweeter at 2.5 kHz. The D15 has two sets of five-way nickel-plated binding posts for those who want to bi-wire or bi-amp the speakers. This is a feature that most upscale speakers are supposed to have but in reality, it is not very useful. The advantages of bi-wiring or bi-amping a speaker like this are negligible and not worth the potential for problems that can occur for those who attempt those types of connections.
All of this technology is set in a very slick MDF cabinet with the aforementioned aluminum front baffle that is 6mm thick. The side panels and bracing are all 18mm with the bracing designed and positioned with FEA analysis for optimal stiffness of the cabinet. The midrange is enclosed within its own heavily-damped compartment in the cabinet so that back waves from the bass drivers do not affect the cone position. A good amount of polyfill stuffing is placed in the cabinet for internal damping. The speaker is set on a square aluminum bass with the choice of spiked feet or rubber feet. The cabinet feels solid and inert.
The Demand D15 speakers look like a well-designed and competent loudspeaker, but, as with any high-end loudspeaker, its objective is ultimately to sound good. Let’s finally give it a listen to see how it achieves that goal...
Listening Sessions
In my 24’ by 13’ (approximately) listening room, I set up the speakers with stand-off distances between the back wall and sidewall, and equal distance between speakers and listening position. The speakers were set up to face the listening position directly. Listening distance from the speakers was about 9 feet. Amplification and processing were handled by a Pioneer Elite SC-55. No room correction equalization was used. Subwoofers were used for some content that contained deep bass frequencies.
Music Listening
One hi-res 96kbps/24-bit
album that I found to be a superb recording on Qobuz is a recent release of
some Bach works: ‘Magnificat’ and ‘Cantata No. 63, Christen, atzet diesen Tag.’
This release, entitled ‘Bach: Magnificat (Live, Chapelle Royale de Versailles),’
comes from the new classical music label Chateau de Versailles Spectacles,
which, as its name suggests, is tied to performances at the historic Chateau de
Versailles. The music was performed by La Chapelle Harmonique, which is a choir
combined with a period-instrument orchestra that was founded by string
instrument player Valentin Tournet in 2017 (when he was a mere 20 years old).
The musical artistry and production is second to none in this recording, and
anyone looking for some of the finest recorded performances of these pieces by
Bach need look no further.
So how did the Definitive Technology D15 speakers sound with such a talented group of musicians performing these exquisite compositions recorded in such a legendary acoustic space? From the first notes, the sound was enthralling. Each musical section was distinct and crystal clear. The vocals, strings, woodwinds, brass, and percussion were all so vividly rendered that I can’t help but use the word holographic, much as I try to avoid it in my reviews. Now, much of these qualities are matters of the recording, so it’s not as if the speakers can make an unremarkable recording sound amazing, but what I learned right away is that the D15 speakers will allow an exceptional recording to fulfill its potential. The tonal balance across vocals and instruments seemed to be very good. The soundstage was outstanding, and each instrumental section was easily localizable. The lead singers had very well-defined positions throughout the width between the speaker’s placement, and the concert hall ambiance extended well beyond the speaker’s boundaries. Bass was well controlled with extension that easily covered the lower frequencies contained within this album. I’m not sure what more one could ask for from a loudspeaker in the reproduction of ‘Bach: Magnificat (Live, Chapelle Royale de Versailles).’ I suppose that a speaker of this design might struggle in a large room if tasked with playing very loud levels, but for a normal-sized room like my 24’ x 13’ room, they had all the dynamic range I could ask for and would be sufficient in this respect for all but extreme SPL junkies. By the end of this album, I knew that the D15 speakers would be a great choice for any lover of classical music.
For something more focused on
a single voice, I found a great choice in the album ‘Birds on a Wire’ by the
duo Dom La Nena and Rosemary Standley who perform together under the name
Ramages. This was another hi-res new release that I found on Qobuz. This is
folk music that is mostly sung in French but there are a handful of songs sung
in English, Spanish, Russian, and Italian. The instrumental accompaniment is
fairly simple and mostly only consists of a cello and guitar but occasionally
other instruments will make a contribution. This is simpler music and gentle
music. Some of the tracks are cheerful and celebratory, but others are
sorrowful, and the cello is a great instrument to evoke sadness. Rosemary
Standley’s smooth voice is the star of this show, and her singing is relaxed
and melodic. Her vocal range may be limited but her control within her range is
excellent.
Standley’s voice sounded lifelike and radiant on the D15 speakers. Her voice was squarely imaged in the center between the speakers. There is no ambiguity in the soundstage of the D15s. The accompanying instruments also had very well-defined positioning. Bass from the plucked cello was strong without being overbearing at louder volumes. The clarity of the individual instruments was terrific even as they took a backseat to the vocals within the recording. These are pretty speakers, so one thought that occurred to me was: were the pretty looks of the speaker biasing my perception of the sound? Maybe, but usually, I suspect pretty speakers put aesthetics and industrial design first and sound reproduction performance second (if even that high up the list in design priorities), however, the overall sound was excellent while listening to ‘Birds on a Wire.’ These aren’t incredibly expensive speakers either. I would have figured that speakers with smooth aluminum front baffle and base with a gloss finish combined with a seriously good sound would cost more than the $3,400 MSRP for the D15s. The speakers that I have heard at audio trade shows that looked and sounded this good were far more expensive than these. How is it that Definitive Technology is able to pull off high-end looks and a high-end sound without a high-end price tag? I would guess the answer is clever design combined with very efficient manufacturing practices (the lack of curvature in the cabinet may be a real advantage in making these speakers affordable). However Definitive Technology accomplished this feat, I am glad they did.
Some years ago I had heard
some songs from Roberto Fonseca that I quite enjoyed, and I had always intended
to further explore more music by him but it just kept slipping my mind. While
browsing through Qobuz’s library, I noticed Fonseca’s latest release, ‘Yesun,’
was available in hi-res, so I finally decided to dive into more of his music to
get a better sense of him as an artist and also to hear what the D15’s could do
with his tunes. Fonseca is a Cuban jazz pianist who borrows styles and sounds
from many different kinds of music but runs them through his Afro-Cuban sensibilities.
There is a wide variety of musical moods and styles on ‘Yesun,’ and some stray
further from Cuban Jazz than others, but the music is always lively, and the
diversity of sound and different instruments here makes this a great album to
demo on a high-fidelity sound system.
As with previous music, the D15s give a clear and lucid presentation of each instrument, so much so that I was able to discern microphone setup with respect to many of the individual instruments. Again, the soundstage was sensational; it imaged over a wide breadth of space yet not at the cost of precision. On certain moments during the album, I cranked the volume loud, and the speakers did not lose their composure. The percussion hit with a visceral snap and thud, and the bass scaled with the mids and treble without compressing. The two bass drivers were capable of more output than I would have expected of 5.25” woofers, and I was duly impressed. This is a percussion-rich music which is great for demonstrating the transient character of sound systems, and each percussive instrument was distinct on the D15s, whether that be snares, congas, cymbals, hi-hats, or bass drums. There was no vagueness or overhang that I could detect, and this immediate response made for a lifelike presentation. As with so much else that I had heard on the D15 speakers, I was not left wanting for any aspect of sound in listening to ‘Yesun.’
One new release on Qobuz that
caught my eye from its title is the compilation ‘Music for Containment.’ It is
33 tracks of abstract and experimental ambient music from artists on the roster
of the French electronic music label Mille Feuilles. This music can be quite
challenging at times and can range from soothing and calm to harsh and grating.
It is strange stuff and certainly not for everyone’s tastes, but I appreciate
the exploration of different sounds that the artists engage in. There is such a
variety of different sounds here that I thought it would be a good show of the
range and ability of the D15 speakers. The title of this album makes it all the
more apt since, as of the time of this writing, I am was under a
Stay-At-Home order in my state thanks to COVID-19. This often dissonant music
is a good reflection of the anxiety of the era of COVID-19, although I am sure
most people would prefer more escapist music in these times, and I can’t blame
them.
The stereo effects employed in many of the tracks in ‘Music for Containment’ are not supposed to be an imitation of a natural audio event, and, instead, they are used for a more conceptual aural space. The D15 speakers adroitly conveyed this use of imaging as a vehicle for an idea rather than a mere reproduction of a traditional soundscape. I have to imagine that the artists of this album probably expected most listeners would listen on headphones, but the atmospheres created by a set of good high-fidelity speakers like the D15s are so much more palpable. The true-to-life imaging, as well as the more tactile bass of loudspeakers, make the listening experience far more concrete than with headphones. It’s not easy to discern the intended sound of many of the tracks on ‘Music for Containment’ owing to their ‘Acousmatic Sound’ philosophy. Nonetheless, the D15s did realize this music with a good sense of coherence and articulation. However puzzling the musical compositions were, the sound itself was always unambiguous, and the D15s offered a clear translation of the source. Each layer of sound remained distinct on the D15s, and each sound was given a detailed rendering. I’m not sure how many people would enjoy ‘Music for Containment,’ but those who do ought to give it a listen on speakers on the level of the D15s; I think it is a much richer experience than headphones can provide.
Movie Watching
One movie I watched with the
Definitive Technology Demand D15 speakers was the 2018 comic book movie
‘Venom.’ I had not seen it before, but I knew it would be an effects-laden
movie, and I wanted to see what the speakers could do with a wide dynamic range
sound mix. I also wanted to see what it could do in terms of bass without a
subwoofer. ‘Venom’ is a major studio production about a guy that gets possessed
by a crazy alien demon thing which gives him superpowers, so it looked like it
would have a pretty far-out sound mix that would be a good demonstration of
dynamic range and low-frequency extension. I cranked the volume and let ‘Venom’
rip on the D15 speakers, and it wasn’t long into the movie when I could hear
the passive radiators overloading. I quickly learned that the D15 speakers are
not happy in deep frequencies at high volumes. While I could crank music to the
same loudness levels and not worry, most music bass does not dig as deep as
modern movie bass. Music, especially acoustic recordings, don’t really dig much
below 40 Hz at high levels, but a lot of modern action and science fiction
movies do. Deep frequencies are far more taxing on bass drivers than stuff
above 40 Hz. I turned on subwoofers and used an 80 Hz crossover point for the
rest of the movie. Once relieved of deep bass duty, the D15 speakers shined.
The Venom characters' acrobatic moves sounded vibrant, and all of the car
crashes, explosions, and gunfire were potently rendered. Dialogue
intelligibility was good as well, and to ensure that was a quality of the D15s,
I had set my processor for two-channel operation, and no center speaker was
used. ‘Venom’ was a wild ride as far as sound mixes go, and the D15 speakers
can certainly take the listener on that journey- as long as their low-frequency
limitatio
ns are understood.
One movie I had been itching to see since its announcement was ‘Once Upon a Time in Hollywood,’ Quinten Tarantino’s fictional saga concerning Hollywood’s brush with Charles Manson. I figured this would be a great way to gauge dialogue intelligibility since Tarantino’s movies are heavily dialogue-based and the production quality would be as good as it gets. Tarantino also fills his movies with loads of music, so they are typically a great way to hear some good tunes as well as Tarantino’s often brilliant dialogue. ‘Once Upon a Time in Hollywood’ did not disappoint me regarding my expectations of its sound mix. One aspect that surprised me was the pervasive use of diagetic music sources as an element of the sound mix. The music often comes through authentic period radio broadcasts or record players that the characters are listening to, complete with commercial breaks and station identification plugs. I did notice that soundtrack fidelity of the music sources would not have sounded as good as the equipment they were ostensibly being reproduced on (I doubt that a 1950’s MG sports car’s radio sounded that good, assuming it even had a radio). However, it was just a clever and perhaps more immersive way to get music to accompany the visuals. The D15 speakers performed superbly in my viewing of ‘Once Upon a Time in Hollywood.’ The music sounded great and dialogue intelligibility was never less than excellent. This movie was alive with constant music sources, so it was good to listen to it on some speakers that didn't inhibit the sound quality. Even though the music was mostly older recordings, I would implore viewers to use a good sound system for films like this. The sound is so much richer than anything a soundbar or home-theater-in-a-box could have managed.
See also:
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Recent Forum Posts:
ILO, post: 1437482, member: 71419In terms of objective measurements, I believe these new D15 towers measure better than any DefTech speakers ever made.
I own Mythos Super Tower STL front speakers (and Gem rear speakers). As I understand Demand series is the replacement for Mythos series. Mythos series were also good looking speakers. Mythos STLs are low distortion modern speakers while the rest of Mythos series were outdated and were rightfully discontinued. Does anyone know how Demand D17 or D15 compare with Mythos STL? I mean does it make sense to replace STLs with D17s (if stay in DefTech family).
These new Demand towers have less bass than the DefTech speakers with built-in powered woofers. But these new Demand towers are more accurate. I think the D15 on-axis response is approximately +/- 1.6dB.
ryanosaur, post: 1405372, member: 86393Is Outlaw doing another 3-Fer for the newer monos? I know they had something going on a few weeks ago…
If you decide you want to go with an external amp, I would recommend something that runs around 200w into 8 ohms/300w into 4 Ohms. Anything less seems foolish, especially considering the lower sensitivity of those speakers. In the end, it's not so much about SPL potential as it should be about having adequate headroom to handle dynamic peaks.
I only bring these up as they are often overlooked… mind, I am a very happy owner of the previous generation… but the Outlaw Monoblock 2220s are reasonably priced and solid performers.
Now, that aside, any amp in your budget that can deliver good clean power without coloring the sound is worthwhile. I am not a fan of Emotiva, but their owners swear by them and say they are great. I cannot speak to their quality or customer service other than to potentially offer some less than stellar hearsay.
Others here like the Crown XL Amps… 1502 and higher would be the usual recommendation. QSC cinema amps are highly regarded as well. (Both are Pro Models and very capable.)
I'm certain others will chime in.
https://outlawaudio.com/shop/index.php?id_product=45&rewrite=model-2220&controller=product
Yes! Not quite a good as the previous 2200 series bundle, but still not bad. 3 x 200 watts for under a grand.
I only bring these up as they are often overlooked… mind, I am a very happy owner of the previous generation… but the Outlaw Monoblock 2220s are reasonably priced and solid performers.
Now, that aside, any amp in your budget that can deliver good clean power without coloring the sound is worthwhile. I am not a fan of Emotiva, but their owners swear by them and say they are great. I cannot speak to their quality or customer service other than to potentially offer some less than stellar hearsay.
Others here like the Crown XL Amps… 1502 and higher would be the usual recommendation. QSC cinema amps are highly regarded as well. (Both are Pro Models and very capable.)
I'm certain others will chime in.