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Definitive Technology Demand Series D9

Bookshelf speakers

6 Reviews

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Item # 735D9

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C$999.99 pair

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Our take on the Definitive Technology Demand Series D9

Definitive Technology has created something that I think our music-loving customers will really enjoy. Their D9 bookshelf speakers combine an attractive cabinet design with high-tech driver technology for natural, full-bodied sound that looks great in your room.

Great looks and stellar sound

Definitive Technology has created something that I think our music-loving customers will really enjoy. Their D9 bookshelf speakers combine an attractive cabinet design with high-tech driver technology for natural, full-bodied sound that looks great in your room.

These sharp-looking speakers feature an aluminum front baffle, along with a top-mounted passive radiator. They're the mid-sized model in Def Tech's Demand Series lineup.

Definitive Technology D9 bookshelf speaker

Each D9 speaker uses an offset tweeter for precise stereo imaging and a wide sweet spot (right speaker shown with grille removed).

A tweeter designed with music in mind

One of the coolest parts of the D9 is its all-new tweeter design. Each speaker uses a 1" annealed (heated and then slowly cooled) aluminum tweeter for super-smooth, natural highs. Each tweeter is offset from its corresponding woofer by 5°, which helps it deliver a precise center image — a crucial component of the stereo listening experience. 

Def Tech employs its Linear Response Waveguide™ on each tweeter, which helps create a wide "sweet spot" and a lifelike soundstage. Each speaker is labeled as "right" or "left" to optimize stereo playback (and for visual reference, the left speaker's tweeter is offset to the left of the woofer, and vice versa for the right speaker).

Solid midrange and bass

The D9s sport a 5-1/4" Balanced Double Surround System (BDSS) polypropylene woofer in each cabinet. These custom-designed drivers deliver articulate midrange and punchy bass. 

Each speaker also features a 5" x 9" racetrack-shaped passive radiator, and a rear-firing port for increased low-end extension.

Get the most out of your stand-mount speakers

I'm a proponent of using high-quality speaker stands with bookshelf speakers. They help improve the sound by giving your speakers a stable, vibration-free platform. When shopping for stands, remember that the ideal height will place the tweeters roughly level with your ears, for maximum clarity.

Speaker stands also give you more placement flexibility, since you won't be limited to a space on your shelf or table. Keeping your speakers away from the wall or the corner of a bookshelf can also prevent excessively boomy bass. Many stands even offer built-in cable management for a neat, clean install.

The Sanus SF22 steel stands are an excellent choice to use with the D9s, but feel free to contact one of our Advisors for a specific recommendation for your setup.

Product Highlights:

  • pair of high-performance bookshelf speakers for music or home theater
  • 1" aluminum dome tweeter with 20/20 Wave Alignment Lens™ for excellent high-frequency performance
    • laterally offset tweeter assembly helps creates a precise center stereo image
  • 5-1/4" BDSS™ (Balanced Double Surround System) polypropylene woofer for smooth midrange and punchy bass
    • Linear Response Waveguide provides smooths off-axis frequency response and even sound dispersion
  • 5" x 9" racetrack-shaped passive radiator for increased bass extension
  • frequency response: 64-22,000 Hz (-3dB)
  • recommended amplifier power: 20-150 watts
  • sensitivity: 88 dB
  • impedance: 8 ohms
  • 5-layer piano black high-gloss finish
  • aluminum front baffle
  • removable magnetic grille
  • two sets of 5-way binding posts for bi-amping or bi-wiring
  • 6-9/16"W x 11-13/16"H x 12-7/16"D each
  • warranty: 5 years
  • Our 60-day money-back guarantee

What's in the Box:

  • Left bookshelf loudpseaker
  • Right bookshelf loudspeaker
  • 2 Grilles
  • 4 Jumper-straps (pre-installed)
  • Cleaning cloth
  • Owner's Manual

Featured Video

Been playing them for two weeks now.Have them in a middle sized bedroom.All I can say WOW......Wow!, Very full sound!!!!!!!!!!!,i'm 65 and still like to rock out, these speakers do that,Have a least 100w system.Bad Ass speakers.

gary ridenour, Martinez,California


Definitive Technology Demand Series D9 Reviews

Average Customer Review(s):

(6 Reviews)

Definitive Technology Demand Series D9

Michael from St Louis, MO on 2/1/2019

Crutchfield Customer Review (What's this?)

Wonderful speakers for a small space. I'm using them in my 15x15 home office and they provide room filling sound. Work well with everything from classical to jazz to rock to electronic. You will need a decent receiver or amp to drive them, but if you're looking at these speakers I expect you already have that. I usually run them between 40 and 60 watts. Staging is excellent, bass is more than adequate without a sub. I have a computer driven equalizer that is very convenient for adjusting between different types of music. Simply wonderful speakers!

Pros: Attractive Design Good Staging Room filling sound Excellent Bass (not overpowering)

Cons: Really need an equalizer to tune properly. They sound a little flat on anything but choral music without the EQ.

Definitive Technology Demand Series D9

Crutchfield customer from Santa Cruz, CA on 12/29/2018

Crutchfield Customer Review (What's this?)

Amazing sound. You can hear each instrument so distinctly and clearly. Highly recommend.



Great at 500 and competes all the way to 1000.

Jimmy from Seattle, WA on 12/15/2018

Better then the elac ub5 better build quality and sound, preferred these to similar price kef, klipsch, elacs, didn't hear vs the dynaudio emits. To get as good a build quality and performance raise you a ls50 and dynaudio excite at 1000. Great speakers at 500 n up till a thousand dollars. Sound superb with instrumental and jazz and even the spin of iron maiden if it fancies you.

Pros: build quality fit and finish

Cons: need good stands

Definitive Technology Demand Series D9

Crutchfield customer from Boynton Beach, FL on 11/6/2018

Crutchfield Customer Review (What's this?)

Excellent sound for a small speaker. Very happy with purchase.




gary ridenour from Martinez,California on 10/22/2018

Crutchfield Customer Review (What's this?)

Been playing them for two weeks now.Have them in a middle sized bedroom.All I can say WOW......Wow!, Very full sound!!!!!!!!!!!,i'm 65 and still like to rock out, these speakers do that,Have a least 100w system.Bad Ass speakers.

Pros: Worth the money.

Cons: Got to have the power to tighten them up!!!!!!

Definitive Technology Demand Series D9

Guest from Ashburn, VA on 1/15/2018

These are great-sounding speakers. Crisp, clear sound and a surprising amount of bass from a small package. They are sharp looking too, and the magnetic grille covers are a great feature. I am very impressed with the sound quality.




Hands-on research

Features and Specs

Enclosure Passive Radiator
Video Shielded No
Tweeter Type Dome
Tweeter Size (inches) 1
Midrange Size (inches) N/A
Woofer Size (inches) 5.25
Woofer Composition Polypropylene
Woofer Surround Rubber
Power Range 20-150
Sensitivity 88 dB
Impedance (Ohms) 8
Frequency Response 64-22k Hz
Connector Type 5-way Post
Bi-amp Inputs Yes
Height (inches) 11-13/16
Width (inches) 6-9/16
Depth (inches) 12-7/16
Weight (pounds) 17
Mounting Bracket Included No
Recommended Stand Height (inches) 24-28
Parts Warranty 5 Years
Labor Warranty 5 Years

Product Research


Demand Series Bookshelf Loudspeakers: The Definitive Technology Demand Series D9 high-performance bookshelf loudspeakers deliver full-range, room-filling sound and precise imaging in a modern, elegant styling. Featuring technology advancements to both Definitive's aluminum dome tweeter and midrange/woofer sections, these speaker deliver an unrivaled sweet spot, smoother high-frequency reproduction, and three-dimensional imaging for a technically-advanced, premium bookshelf listening experience.

1" Aluminum Dome Tweeter: The 1" annealed aluminum tweeter is precision engineered to articulate nuance and detail in the high-frequency bands for a crystal-clear listening experience. Offsetting the tweeter by 5° delivers a more precise center stereo image by eliminating undesirable symmetric diffraction off the corners of the front baffle.

  • 20/20 Wave Alignment Lens: Coupled with Definitive's new 20/20 Wave Alignment Lens, the 1" annealed aluminum dome tweeter delivers smoother high frequency response and improved dispersion for a rich and balanced listening experience.
  • Linear Response Waveguide: A patented Linear Response Waveguide extends both on and off axis frequency response, while improving dispersion for more natural mid-range timbre and more precise imaging.
Note: Because the tweeters are offset, the bookshelf speakers are labeled for left (L) and right (R) on back of the cabinet.

5.25" BDSS (Balanced Double Surround System) Midrange/Woofer: A patented 5.25" Balanced Double Surround System (BDSS) polypropylene midrange/woofer provides greater excursion and output that results in superior midrange detail and punchier bass compared to drivers of similar size. The speaker's balanced double surrounds support the cone at two points to provide better mechanical stability for longer, more linear excursion, and improved damping to suppress cone resonance.

Passive Bass Radiator: A top-mounted oval 5" x 9" passive bass radiator in each bookshelf speaker produces superior low-end extension. Plus, the addition of a larger spider reduces rocking and increases linearity for deep, tight, clean bass response.

Hand Crafted Cabinet: The speaker cabinets are constructed from MDF with an extruded natural bead-blasted aluminum front baffle. The cabinets are hand-crafted, meticulously sanded, painted with five layers of premium black gloss paint, and then buffed for a near-mirror finish (Level 6) for an uncompromising look in your home.

Acoustically Transparent Magnetic Grille: Each bookshelf loudspeaker also comes with an acoustically transparent black magnetic grille. The included acoustically transparent magnetic black speaker grilles provide natural, uncolored sound when placed on the speaker, and remove easily when you want to enjoy looking at them fully uncovered.

Gold-Plated, Dual Binding Posts: Each bookshelf speaker has two sets of gold-plated, 5-way binding posts connected by jumper-straps. The gold-plated binding posts will accept bare wire (up to 10AWG), pin connectors, spade-lugs, & banana plugs (single or dual). Using the dual posts, you can bi-wire or bi-amp the speakers. Bi-wiring or bi-amping the speaker provides improved bass & treble performance.

  • Bi-Wiring: Bi-wiring can provide noticeable improvements in the overall transparency of your loudspeakers. Run separate speaker wires to the low & high frequency drivers from a single amplifier (the upper set of binding posts are for the high frequency drivers; the lower set of binding posts are for the low frequency drivers).
  • Bi-Amping: Bi-amping allows you to use separate amplifiers for the high & low frequency sections of your loudspeaker for greater dynamic range & lower distortion. We recommend that your separate amplifiers have identical gain to preserve the speaker's voicing balance.
  • If you decide to bi-wire or bi-amp, you must remove the jumper-straps between the terminal posts on both speakers (failure to do this could result in damage to your amplifier and loudspeakers).
  • In order to use banana plugs, you must completely unscrew the binding-post terminals and remove the rubber caps. Once you have removed the rubber caps, you can fully screw down the binding-post terminals and connect your banana plugs (sold separately).

Mounting Options: The Demand Series D9 bookshelf speakers can simply be placed on a speaker stand, desk, table or shelf. Definitive offers a speaker stand (735DST1, sold separately) specifically designed for the Demand Series bookshelf speakers. Integrated rubber pads on the bottom of the speakers provide stability and protection. You can use the Pinpoint side-clamping brackets (sold separately - see Accessories tab) to wall mount the speakers.

Note: This speaker does not offer a threaded insert or keyhole slot for wall-mounting.

Placement: The D9 bookshelf loudspeakers and your main listening position should be setup in an equilateral triangle that measures 7-10' from each speaker and the listening position. The speakers should be placed approximately 2-6' from side walls and 2-4' from back walls. The speakers should be mounted as close to ear level as possible with the listening position. Toeing the speakers in slightly, toward your listening area will provide stronger stereo imaging.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.