Used Definitive Technology Demand D15 Floorstanding Speaker, Left, Piano Black

Tall, slim speakers are certainly in fashion, and it's hard to imagine many slimmer than Definitive Technology's new Demand Series D15 towers. Despite housing three 5.25-inch drivers (two carbon fiber woofers and a polypropylene midrange), a 1-inch aluminum dome tweeter, and not one but two 8-inch side-firing passive radiators, the D15 measures just 6.5 inches wide and thus indeed requires its bolt-on aluminum bottom plinth to achieve stability.

Def Tech has always balanced serious value with serious performance, and the Demand series clearly maintains the tradition. But while the firm's top-range calling card has from inception been bipolar designs, with both forward- and rearward-radiating drivers and on-board powered "subwoofer" bass sections, the Demand series breaks rank, placing conventional, monopole (forward-only), fully passive designs at the top, price-wise at least, of Def Tech's offerings for the first time.
The D15 is the second of two Demand series tower designs; the slightly larger and costlier D17 employs 6.5-inch drivers and 10-inch passive radiators yet specifies bass extension only a few Hertz lower with a modest 2 dB gain in sensitivity. To fill out our test system, the company included the Demand D5C center-channel unit and a pair of D9s, the middle of three bookshelf speaker offerings, for the surround channels, all in the gloss-white lacquer that is one of two finish options (piano black's the other).

Tall, slim towers producing smooth octave-to-octave balance across the house, resonance-free response; broad, gradually falling-off dispersion; and smoothly contoured, generally similar off-axis responses.
These once-rare virtues are encountered ever more frequently, thanks at least in part to the computer-aided engineering, modeling, and measurement that have become common practice. This leads in turn to what many might characterize as a boring sameness of result. Boring, that is, only in the sense that most airline flights, thanks to aviation's own advanced technologies, produce similar results: reliably smooth, crash-free trips.
The Demand Series D15 towers, in short, are very fine reproducers, and in any room they sound considerably fuller-range than their fairly modest 48 Hz (-3 dB) bass extension spec suggested. The track "Royals" (24-bit/48kHz FLAC, Qobuz) by Lorde opens with a loose orchestral bass-drum strike (real or synthesized—I can no longer tell these days), with fundamentals probably around 40 Hz or so and dipping lower on the decay that obligingly repeats every downbeat.

D15 Tower Speaker - Spacious Expansive Sound
Demand Series D15 loudspeakers deliver smooth high-frequency reproduction, formidable lows, and room-filling three-dimensional imaging for expansive audio.

• Full-Range, Room-Filling Sound: 3-Way Configuration and Audiophile-quality Crossovers
• High-Frequency Performance: Laterally Offset Tweeters for a Precise Soundstage
• Superior Midrange and Punchier Bass: Balanced Double Surround System and 6.5" Mid/Bass Woofers

Room-filling Sonic Performance

Lose Yourself In Sound
The D15 tower speaker features an exclusive 3-way driver configuration with a 1" annealed aluminum dome tweeter, a 5.25" BDSS midrange woofer, and dual 5.25" carbon fiber bass drivers, complemented by dual 8" side-firing passive radiators, for a full-range, room-filling sonic performance.

Proprietary Drivers detailed, balanced audio
Definitive Technology designed the drivers in the Demand Series to deliver a perfectly balanced, precise, musical sound.

Tweeters - Clear, Precise Highs
The D15 couples a laterally offset 1" Aluminum Dome Tweeter with our 20/20 Wave Alignment Lens. We offset the tweeters by 5 degrees, minimizing wave cancellations off the front baffle to deliver a more precise center stereo image and ensure clear, detailed high-frequency performance.

Midrange - Superior Detail & Natural Midrange
The D15's 5.25" patented Balanced Double Surround System (BDSS) mid/bass driver provides greater excursion and output for superior midrange detail and punchier bass compared with other drivers of similar size.

Woofers - Deeper, Cleaner Bass
The D15's 5.25" custom-woven carbon fiber woofers produce superior cone rigidity for deep, evenly extended bass notes while preventing distortion-causing cone deformation that can occur with less rigid materials.

Dual 8" Passive Bass Radiators for visceral bass response
Twin integrated 8" passive bass radiators in each speaker produce superior low-end extension for highly controlled, highly impactful bass.

Audiophile-Quality Crossovers for beautifully balanced audio
Demand Series crossovers are built with the latest premium audiophile-quality parts, including polypropylene metal-film capacitors and air-core inductors. These high-end components meticulously manage frequencies for clean and crystalline treble, refined and articulate midrange, and linear, low-distortion bass. This ensures that every detail comes through within a clear, balanced presentation that never sacrifices power.

Linear Response Waveguide for natural, precise imaging
Our patented Linear Response Waveguide extends both on-axis and off-axis frequency dispersion for more natural midrange timbre and precise imaging.

Masterful Sound

Award Winning Home Cinema
True audiophiles are obsessive about all sound, not just their music. The meticulous attention to detail that enables the D15 Tower Speaker to beautifully reproduce music also enables it to flawlessly reproduce home theater audio.

Artistry to the eye and ear
Extruded aluminum front baffles capture a clean, modern aesthetic with a bead-blasted finish to fit any decor.

Each speaker is meticulously sanded and painted with five layers of premium gloss paint, then buffed to a near-mirror finish for an undeniably fashionable look in your home.