In this review, we will be comparing two different type of speakers . Definitive Technology Demand D15 is a Floor-standing speaker whereas the Q350 is a Bookshelf speaker.
Let's have a brief look at the main features
of Definitive Demand D15 and KEF Q350 first before getting into our more
detailed comparison.
Definitive Demand D15 Key Specs
- 3-way Design
- 1" dome Tweeter
- 5.25" Midrange
- 2 x 5.25" Carbon-fiber Woofer
- 48-22k Hz Frequency Response
- 85.5 dB Sensitivity
- Impedance: 8ohms
- Power Range:30-300watts
- Weight:23.60kg
- Dimensions (H x W x D): 1023.0" x 9-1/16" x 12-3/4"( 1023.0 x 231.0 x 324.0mm )
KEF Q350 Key Specs
- 2-way Design
- 11th Generation Uni-Q Driver
- 1" Dome Tweeter
- 6.5" Aluminum Woofer
- 63-28k Hz Frequency Response
- 87 dB Sensitivity
- Impedance: 8ohms
- Power Range:10-120watts
- Weight:7.60kg
- Dimensions (H x W x D): 358.0" x 8.2" x 12.0"( 358.0 x 210.0 x 306.0mm )
What size room are the Definitive Demand D15 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 D15 |
KEF Q350 |
| Near-field |
Bad |
Poor |
| Small Room |
Poor |
Average |
| Mid-size Room |
Average |
Good |
| Large Room |
Good |
Average |
| Very Large Room |
Average |
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.)
In the following sections, we will get into more detail in order to better understand how the Definitive Demand D15 and KEF Q350 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
**This post contains affiliate links, and I will be compensated if you make a purchase after clicking
through my links. As an Amazon Associate I earn from qualifying purchases.
Drivers
One of the fundamental differences between these two speakers is that Demand D15 is a 3-way design whereas the Q350 is a 2-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.
| Driver |
Definitive Demand D15 |
KEF Q350 |
|
Driver Setup
|
3-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
1 x 5.25-inch |
- |
|
Woofer
|
2 x 5.25-inch
|
1 x 6.5-inch
|
Demand D15 features a 1" aluminum dome Tweeter , a 5.25" Midrange and 2 x 5.25" Carbon-fiber 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 D15 has a frequency range of 48-22k Hz whereas Q350 has a frequency range of 63-28k Hz. With a minimum frequency of 48Hz, the Demand D15 can go significantly deeper on the low side and provide stronger bass compared to the Q350's min frequency of 63Hz.
Below graphs depict how these two speakers compare with the max, min and average values of the Min and Max Frequencies of other speakers in the Floor-standing class in our database.
Low Frequency
Floor-standing Speakers
High Frequency
Floor-standing Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
Demand D15 and Q350 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. Demand D15 sensitivity is rated at 85.5 dB and the Q350's is at 87 dB. This 1 dB difference makes the KEF Q350 a more sensitive speaker compared to Definitive Demand D15, hence will play louder with the same amount of watts.
Sensitivity
Floor-standing Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. While using an amplifier within this range ensures the nominal performance , inputting a power that is higher than the max wattage can result in a damaged speaker.
Demand D15 can handle a max power of 300 watts RMS from the amp the whereas Q350 has a max power handling value of 120 watts RMS, 180 watts less than the Demand D15.
Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker
compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters
such as Impedance, sensitivity and system efficiencies.
Input Type and Bi-Amping / Bi-Wiring
Demand D15 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.
Definitive Demand D15's 5-Way post terminals allows Bi-amping or bi-wiring
KEF Q350's Post terminals
Physical Specs
Size of a speaker can sometimes become 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 D15's and KEF Q350's external dimensions. Definitive Demand D15 has external dimensions of 1023.0 x 231.0 x 324.0mm ( 40-1/4 x 9-1/16 x 12-3/4inch) 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 D15 is clearly the larger of the two speakers. Its body is 21mm wider, 665mm taller and 18mm deeper than KEF Q350.
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 D15 is approximately 748.4cm2 / 116.0inch2 and base area of the KEF Q350 is approximately 642.6cm2 / 99.6inch2. The Demand D15 requires 16% more surface area than the Q350 which gives it a small disadvantage on placement in tight spaces.
What's in the Box of Definitive Demand D15?
Here are the items that are included inside the box of Demand D15:
Left floorstanding loudspeakerRight floorstanding loudspeaker2 Grilles4 Jumper-straps (pre-installed)2 Bases8 Spike feet8 Floor-glides8 Lock-rings8 ScrewsCleaning clothOwners 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 
Driver Setup 
Number of Woofers 
Bi-Amping and Bi-Wiring 
Passive Radiator 
Sensitivity 
High Frequency Response 
Height 
Base Surface Area 
Price per pair*