In this review, we will be comparing Motion F20 and R7, two Passive Floor-standing speakers from MartinLogan and KEF. Let's have a brief look at the main features
of MartinLogan Motion F20 and KEF R7 first before getting into our more
detailed comparison.
What size room are the MartinLogan Motion F20 and KEF R7 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 Motion F20 and KEF R7 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 F20 and R7 are 3-way speakers.
| Driver |
MartinLogan Motion F20 |
KEF R7 |
|
Driver Setup
|
3-way
|
3-way
|
|
Tweeter
|
1.0 x 1.4-inch
|
1-inch
|
|
Midrange
|
1 x 5.5-inch |
1 x 5-inch |
|
Woofer
|
2 x 5.5-inch
|
2 x 6.5-inch
|
Motion F20 features a 1.0 x 1.4" Folded Motion Ribbon Tweeter , a 5.5" Midrange and 2 x 5.5" Aluminum Woofer with a Crossover frequency at 230Hz and 2600Hz. On the other hand, the R7 features a 1" aluminum Dome Tweeter , a 5" Midrange and 2 x 6.5" Hybrid Aluminum Woofer with a Crossover frequency at 400Hz and 2900Hz.
Frequency Response
Motion F20 has a frequency range of 35-25k Hz whereas R7 has a frequency range of 48-28k Hz. With a minimum frequency of 35Hz, the Motion F20 can go significantly deeper on the low side and provide stronger bass compared to the R7's min frequency of 48Hz.
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
Motion F20 is a 4 ohms speaker compared to the R7 which has a nominal impedance of 8 ohms. Lower impedance speakers, especially the ones that are rated at 4 ohms may put more pressure on the amplifier unit especially when played at high volume levels, so make sure the amp you pair with the Motion F20 can provide this impedance level.
These two speakers also have different sensitivity levels. Motion F20 sensitivity is rated at 92 dB and the R7's is rated at 88 dB. This 4 dB difference makes the MartinLogan Motion F20 a more sensitive speaker compared to KEF R7, 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.
Motion F20 can handle a max power of 300 watts RMS from the amp the whereas R7 has a max power handling value of 250 watts RMS, 50 watts less than the Motion F20.
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
Both Motion F20 and R7 features dual binding post speaker terminals for bi-amping or bi-wiring.
MartinLogan Motion F20's Custom 5-way bi-wire tool-less binding posts terminals allows Bi-amping or bi-wiring
KEF R7's Binding post terminals allows Bi-amping or bi-wiring
Cabinet Type and Port Position
Motion F20 has a bottom firing port whereas R7 has a rear firing ports. MartinLogan Motion F20's bottom-firing port gives more flexibility in placement in regards to proximity to walls compared to KEF R7 with its rear-firing 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 Motion F20's and KEF R7's external dimensions. MartinLogan Motion F20 has external dimensions of 1127 x 298 x 362mm ( 44-3/4inch x 11-3/4inch x 14-1/4inch ) whereas KEF R7 has external dimensions of 1113.0 x 200.0 x 389.0mm ( 43-13/16 x 8 x 15-5/16inch) .
KEF R7 is 98mm narrower and 14mm shorter than MartinLogan Motion F20 but it is also 27mm deeper.
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 Motion F20 is approximately 1078.8cm2 / 167.2inch2 and base area of the KEF R7 is approximately 778.0cm2 / 120.6inch2. The Motion F20 requires 39% more surface area than the R7 which gives it a small disadvantage 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 Motion F20 weighs 27.20kg / 59.8lbs and the KEF R7 weighs 31.40kg / 69.1lbs. This makes the R7 15% heavier than the Motion F20.
Here is a comparison of how Motion F20 and R7's weights compare with the average, max and min weights in Passive Floor-standing class.
Weight
All Floor-standing Speakers
What's in the Box of KEF R7?
Here are the items that come with the R7:
Floorstanding loudspeakerGrille2 Foam port plugs4 Outrigger feet4 Spikes4 Protective discs4 Screws4 WashersWrenchHex-keyUser ManualWarranty Information
 Max Input Power |
300 watts
vs
250 watts
|
Handle more power from your amplifier |
 Sensitivity |
92 dB
vs
88 dB
|
Play louder with same amount of amplification power |
 Low Frequency Response |
35 Hz
vs
48 Hz
|
Generates deeper bass |
 Price per pair* |
3498USD
vs
4500USD
|
costs less (*prices may change depending on the seller, location and time) |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
| Woofer Size |
6.5 inches
vs
5.5 inches
|
Larger woofer |
 High Frequency Response |
28k Hz
vs
25k Hz
|
Generates higher frequency |
 Height |
1113mm
vs
1127mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
778cm2 (200x389mm)
vs
1078cm2 (298x362mm)
|
Takes less floor space |
| General |
MartinLogan Motion F20 |
KEF R7 |
| Brand |
MartinLogan |
KEF |
| Speaker Type |
Floor-standing speaker |
Floor-standing speaker |
| Power Range |
20-300 watts |
15-250 watts |
| Sensitivity |
92 dB |
88 dB |
| Impedance |
4 ohms |
8 ohms |
| Impedance |
n/a |
3.2 ohms |
| Frequency Response |
35-25k Hz |
48-28k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
5.5" |
6.5" |
| Woofer Composition |
Aluminum |
Hybrid Aluminum |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1.0 x 1.4" |
1" |
| Tweeter Type |
Folded Motion Ribbon |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
5.5" |
5" |
| Crossover Frequency |
230Hz and 2600Hz |
400Hz and 2900Hz |
| Firing Direction |
bottom |
rear |
| Suggested Break-in Period |
Allow 72 hours of break-in |
n/a |
Physical Specs |
|
|
| Height |
1127.0mm (44.4") |
1113.0mm (43.8") |
| Width |
298.0mm (11.7") |
200.0mm (7.9") |
| Depth |
362.0mm (14.3") |
389.0mm (15.3") |
| Weight |
27.20kg (59.8lbs) |
31.40kg (69.1lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
n/a |
MDF/Lacquer |
| Available Colors |
Gloss Black, Walnut, and Satin White |
Black Gloss, White Gloss, Walnut |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
Yes |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |