In this review, we will be comparing Demand D11 and Q350, two Passive Bookshelf speakers from Definitive Technology and KEF.
Let's have a brief look at the main features
of Definitive Demand D11 and KEF Q350 first before getting into our more
detailed comparison.
| Key Specs | Definitive Demand D11 | KEF Q350 |
|---|
| Brand | Definitive Technology
United States · founded 1990 | KEF
United Kingdom · founded 1961 |
|---|
| Design | 2-way | 2-way |
|---|
| Uni-Q driver | — | 11th Generation Uni-Q |
|---|
| Tweeter | 1" Hard-Dome | 1" Dome |
|---|
| Woofer | 6.5" Polypropylene | 6.5" Aluminum |
|---|
| Frequency response | 61-22k Hz | 63-28k Hz |
|---|
| Sensitivity | 90 dB | 87 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 20-200 watts | 10-120 watts |
|---|
| Weight | 8.64kg / 19lbs | 7.60kg / 16.7lbs |
|---|
| Dimensions (H x W x D) | 13-1/16" x 7-5/16" x 12-15/16"
332.0 x 186.0 x 329.0mm | 14.0" x 8.2" x 12.0"
358.0 x 210.0 x 306.0mm |
|---|
What size room are the Definitive Demand D11 and KEF Q350 speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision
factor. Here we have compared their suitability to various sizes of environments considering their size
and max power parameters:
| Listening Environment* |
Definitive Demand D11 |
KEF Q350 |
| Near-field |
Poor |
Poor |
| Small Room |
Average |
Average |
| Mid-size Room |
Good |
Good |
| Large Room |
Average |
Average |
| Very Large Room |
Poor |
Poor |
(* Approximate Room sizes: Small < 100sq. ft / 9 m2,
Mid-size: 100-220 sq. ft / 9-20 m2, Large 220-400 sq. ft / 20-36 m2, Very Large: >
400 sq. ft / 36 m2.
Average Floor Height: 9" / 2.7m. Typical room sizes differ from country to country, and the actual
listening experience changes depending on floor height, room shape, surface materials, listening
position, speaker locations, etc.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both Demand D11 and Q350 are 2-way speakers.
Definitive Demand D11KEF Q350
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Definitive Demand D11 |
KEF Q350 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 6.5-inch
|
1 x 6.5-inch
|
Demand D11 features a 1" Hard-Dome Tweeter and 1 x 6.5" Polypropylene Woofer. On the other hand, the Q350 features a 1" vented aluminum Dome Tweeter and 1 x 6.5" Aluminum Woofer with a Crossover frequency at 2500Hz.
Frequency Response
Demand D11 has a frequency range of 61-22k Hz whereas Q350 has a frequency range of 63-28k Hz. With a minimum frequency of 61Hz, the Demand D11 can go slightly deeper then the Q350's min frequency of 63Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
Neither pair reaches down to 20Hz, the usual definition of full-range, which is normal for speakers of this size. If you want the bottom octave for movies or bass-heavy music, add a subwoofer to whichever you choose. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
Demand D11 and Q350 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. Demand D11 sensitivity is rated at 90 dB and the Q350's is at 87 dB. This 3 dB difference makes the Definitive Demand D11 a more sensitive speaker compared to KEF Q350, hence will play louder with the same amount of watts.
Sensitivity
Bookshelf Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
Demand D11 can handle a max power of 200 watts RMS, whereas Q350 has a max power handling value of 120 watts RMS, 80 watts less than the Demand D11.
Note that higher power handling does not make a speaker louder: that depends mainly on
sensitivity and impedance. The calculator below shows how loud each of these actually plays
on a real amplifier.
Which plays louder on your amplifier?
Starting with a popular amplifier - change it to the one you own, or any you are
considering, and watch both numbers move.
Input Type and Bi-Amping / Bi-Wiring
Demand D11 features 5-Way post posts which make bi-amping or bi-wiring possible. Q350 has a Post which doesn't feature bi-amping/bi-wiring.
KEF Q350's Post terminals
Physical Specs
The size of a speaker can sometimes be an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Definitive Demand D11's and KEF Q350's external dimensions. Definitive Demand D11 has external dimensions of 332.0 x 186.0 x 329.0mm (13-1/16 x 7-5/16 x 12-15/16inch) whereas KEF Q350 has external dimensions of 358.0 x 210.0 x 306.0mm (14.0 x 8.2 x 12.0inch).
Definitive Demand D11 is 24mm narrower and 26mm shorter than KEF Q350 but it is also 23mm deeper.
Below you can see the front view size comparison of Definitive Demand D11 and KEF Q350 in scale.
Comparison image of Definitive Demand D11 and KEF Q350 Size and External Dimensions
Base Surface Area Comparison
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base surface area of the Definitive Demand D11 is approximately 611.9cm2 / 94.8inch2 and base area of the KEF Q350 is approximately 642.6cm2 / 99.6inch2. The Demand D11 requires 5% less surface area than the Q350 which gives it a small advantage on placement in tight spaces.
Here is another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:
Size Comparison image of Definitive Demand D11 and KEF Q350 on a Media Console
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The Definitive Demand D11 weighs 8.64kg / 19lbs and the KEF Q350 weighs 7.60kg / 16.7lbs. This makes the Demand D11 14% heavier than the Q350.
Here is a comparison of how Demand D11 and Q350's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Definitive Demand D11?
Here are the items that are included inside the box of Demand D11:
- Left bookshelf loudpseaker
- Right bookshelf loudspeaker
- 2 Grilles
- 4 Jumper-straps (pre-installed)
- Cleaning cloth
- Owners Manual
What's in the Box of KEF Q350?
Here are the items that come with the Q350:
- 2 Bookshelf loudspeakers
- 2 Foam port plugs
- 8 Self-adhesive rubber feet
- Owner's Manual
- Warranty Registration Card
 Max Input Power |
200 watts
vs
120 watts
|
Handle more power from your amplifier |
 Sensitivity |
90 dB
vs
87 dB
|
Play louder with same amount of amplification power |
 Low Frequency Response |
61 Hz
vs
63 Hz
|
Generates deeper bass |
 Bi-Amping and Bi-Wiring |
Yes
vs
No
|
Allows bi-amping and bi-wiring connections |
 Height |
332mm
vs
358mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
611cm2
vs
642cm2
|
Takes less floor space |
 High Frequency Response |
28k Hz
vs
22k Hz
|
Generates higher frequency |
 Price per pair* |
750USD
vs
999USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Definitive Technology Demand Series D11 |
KEF Q350 |
| Brand |
Definitive Technology |
KEF |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
20-200 watts |
10-120 watts |
| Sensitivity |
90 dB |
87 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
n/a |
3.7 ohms |
| Frequency Response |
61-22k Hz |
63-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
Polypropylene |
Aluminum |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Hard-Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
2500Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
332.0mm (13.1") |
358.0mm (14.1") |
| Width |
186.0mm (7.3") |
210.0mm (8.3") |
| Depth |
329.0mm (13") |
306.0mm (12") |
| Weight |
8.64kg (19lbs) |
7.60kg (16.7lbs) |
| Enclosure |
Passive Radiator |
Bass Reflex |
| Finish |
MDF/Aluminum |
MDF/Vinyl-wrapped |
| Available Colors |
Gloss White,Piano Black |
Black, Walnut, White |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
24-28" |
18-24" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
No single best speaker here - they are built to different priorities, and the right one depends on your room, your amplifier and what you listen to.
| Area | Better | Why |
|---|
| Bass | evenly matched | Much the same reach (61Hz vs 63Hz). |
| Amplifier needs | A | Definitive Demand D11 is more sensitive (90dB vs 87dB), so it goes louder on the same amplifier. |
| Headroom | A | Definitive Demand D11 takes more power (200W vs 120W) - more in hand in a big room. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Cabinet | depends | Passive Radiator vs Ported. |
| Expandability | A | Definitive Demand D11: bi-amping. |
| Price | B | KEF Q350 is cheaper - $750 against $999, about 25% less. |
A Definitive Demand D11 B KEF Q350
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Definitive Demand D11 leads across most of the measured areas for a fairly modest premium, which makes it the easier pick if the budget stretches. KEF Q350 is the one to take if it does not. If your amplifier is modest, vintage or valve-based, Definitive Demand D11 is the safer partner - the other will want more current or more watts to sound its best.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.