In this review, we will be comparing Motion 15 and Q150, two Passive Bookshelf speakers from MartinLogan and KEF. Let's have a brief look at the main features
of MartinLogan 15 and KEF Q150 first before getting into our more
detailed comparison.
What size room are the MartinLogan 15 and KEF Q150 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:
In the following sections, we will get into more detail in order to better understand how the MartinLogan 15 and KEF Q150 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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Drivers
Both Motion 15 and Q150 are 2-way speakers.
| Driver |
MartinLogan 15 |
KEF Q150 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1.0 x 1.4-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 5.25-inch
|
Motion 15 features a 1.0 x 1.4" Folded Motion Tweeter and 1 x 5.25" Aluminum Woofer with a Crossover frequency at 2700Hz. On the other hand, the Q150 features a 1" vented aluminum Dome Tweeter and 1 x 5.25" Aluminum Woofer with a Crossover frequency at 2500Hz.
Frequency Response
Motion 15 has a frequency range of 60-25k Hz whereas Q150 has a frequency range of 51-28k Hz. With a minimum frequency of 51Hz, the Q150 can go significantly deeper on the low side and provide stronger bass compared to the Motion 15's min frequency of 60Hz.
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 Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf 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
Motion 15 is a 5 ohms speaker compared to the Q150 which has a nominal impedance of 8 ohms.
These two speakers also have different sensitivity levels. Motion 15 sensitivity is rated at 92 dB and the Q150's is rated at 86 dB. This 6 dB difference makes the MartinLogan 15 a more sensitive speaker compared to KEF Q150, 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. 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.
Motion 15 can handle a max power of 200 watts RMS from the amp the whereas Q150 has a max power handling value of 100 watts RMS, 100 watts less than the Motion 15.
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
Motion 15 features Post type posts and Q150 has a Post type posts. None of these speakers feature bi-amping/bi-wiring.
KEF Q150's Post terminals
Cabinet Type and Port Position
Both Motion 15 and Q150 have rear firing ports. Rear ported speakers generally need more room between the backside of the speaker and the wall compared to sealed and front/bottom ported speakers. Placing the speakers too close to the walls may cause the bass to sound boomy.
If you are limited in space and can't get the speakers away from the backwall, check our Speakers with Front Firing Ports page.
KEF Q150 Port
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 MartinLogan 15's and KEF Q150's external dimensions. MartinLogan 15 has external dimensions of 290.0 x 173.0 x 240.0mm ( 11.4 x 6.8 x 9.4inch) whereas KEF Q150 has external dimensions of 303.0 x 180.0 x 278.0mm ( 11.9 x 7.0 x 10.9inch) .
KEF Q150 is clearly the larger of the two speakers. Its body is 7mm wider, 13mm taller and 38mm deeper than MartinLogan 15.
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 MartinLogan 15 is approximately 415.2cm2 / 64.4inch2 and base area of the KEF Q150 is approximately 500.4cm2 / 77.6inch2. The Motion 15 requires 17% less surface area than the Q150 which gives it a small advantage on placement in tight spaces.
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 MartinLogan 15 weighs 5.40kg / 11.9lbs and the KEF Q150 weighs 5.60kg / 12.3lbs. This makes the Q150 4% heavier than the Motion 15.
Here is a comparison of how Motion 15 and Q150's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of MartinLogan 15?
Here are the items that are included inside the box of Motion 15:
Bookshelf loudspeaker Grille 4 Rubber feet Users Manual Warranty/Registration Information
What's in the Box of KEF Q150?
Here are the items that come with the Q150:
2 Bookshelf loudspeakers 2 Foam port plugs 8 Self-adhesive rubber feet Owner's Manual Warranty Registration Card
 Max Input Power |
200 watts
vs
100 watts
|
Handle more power from your amplifier |
 Sensitivity |
92 dB
vs
86 dB
|
Play louder with same amount of amplification power |
 Height |
290mm
vs
303mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
415cm2 (173x240mm)
vs
500cm2 (180x278mm)
|
Takes less floor space |
 Nominal Impedance |
8 ohms
vs
5 ohms
|
Less selective with amplifiers |
 Low Frequency Response |
51 Hz
vs
60 Hz
|
Generates deeper bass |
 High Frequency Response |
28k Hz
vs
25k Hz
|
Generates higher frequency |
| General |
MartinLogan Motion 15 |
KEF Q150 |
| Brand |
MartinLogan |
KEF |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
20-200 watts |
10-100 watts |
| Sensitivity |
92 dB |
86 dB |
| Impedance |
5 ohms |
8 ohms |
| Impedance |
n/a |
3.7 ohms |
| Frequency Response |
60-25k Hz |
51-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
5.25" |
| Woofer Composition |
Aluminum |
Aluminum |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1.0 x 1.4" |
1" |
| Tweeter Type |
Folded Motion |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2700Hz |
2500Hz |
| Firing Direction |
rear |
rear |
| Suggested Break-in Period |
Allow 72 hours of break-in at 90 dB |
n/a |
Physical Specs |
|
|
| Height |
290.0mm (11.4") |
303.0mm (11.9") |
| Width |
173.0mm (6.8") |
180.0mm (7.1") |
| Depth |
240.0mm (9.4") |
278.0mm (10.9") |
| Weight |
5.40kg (11.9lbs) |
5.60kg (12.3lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Piano Lacquer |
MDF/Vinyl-wrapped |
| Available Colors |
Gloss Black, Matt White, Red Walnut |
Black, Walnut, White |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
24-30" |
18-24" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Yrs w/ Registration |
5 Years |
| Labor Warranty |
5 Yrs w/ Registration |
5 Years |