In this review, we will be comparing ESL 9 and R7, two Passive Floor-standing speakers from MartinLogan and KEF. Let's have a brief look at the main features
of MartinLogan ESL 9 and KEF R7 first before getting into our more
detailed comparison.
What size room are the MartinLogan ESL 9 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 ESL 9 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
One of the fundamental differences between these two speakers is that ESL 9 is a 2-way design whereas the R7 is a 3-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 |
MartinLogan ESL 9 |
KEF R7 |
|
Driver Setup
|
2-way
|
3-way
|
|
Tweeter
|
9.2 x 44-inch
|
1-inch
|
|
Midrange
|
- |
1 x 5-inch |
|
Woofer
|
2 x 8-inch
|
2 x 6.5-inch
|
ESL 9 features a 9.2 x 44" curved electrostatic transducer Tweeter and 2 x 8" high-excursion paper cone Woofer . 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
ESL 9 has a frequency range of 34-23k Hz whereas R7 has a frequency range of 48-28k Hz. With a minimum frequency of 34Hz, the ESL 9 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
ESL 9 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 ESL 9 can provide this impedance level.
These two speakers also have different sensitivity levels. ESL 9 sensitivity is rated at 90 dB and the R7's is rated at 88 dB. This 2 dB difference makes the MartinLogan ESL 9 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.
ESL 9 can handle a max power of 400 watts RMS from the amp the whereas R7 has a max power handling value of 250 watts RMS, 150 watts less than the ESL 9.
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 ESL 9 and R7 features dual binding post speaker terminals for bi-amping or bi-wiring.
MartinLogan ESL 9's Binding post terminals allows Bi-amping or bi-wiring
KEF R7's Binding post terminals allows Bi-amping or bi-wiring
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 ESL 9's and KEF R7's external dimensions. MartinLogan ESL 9 has external dimensions of 1520.0 x 266.0 x 647.0mm ( 59-13/16 x 10-7/16 x 25-7/16inch) whereas KEF R7 has external dimensions of 1113.0 x 200.0 x 389.0mm ( 43-13/16 x 8 x 15-5/16inch) .
MartinLogan ESL 9 is clearly the larger of the two speakers. Its body is 66mm wider, 407mm taller and 258mm deeper than KEF R7.
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 ESL 9 is approximately 1721.0cm2 / 266.8inch2 and base area of the KEF R7 is approximately 778.0cm2 / 120.6inch2. The ESL 9 requires 121% 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 ESL 9 weighs 35.45kg / 78lbs and the KEF R7 weighs 31.40kg / 69.1lbs. This makes the ESL 9 13% heavier than the R7.
Here is a comparison of how ESL 9 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 MartinLogan ESL 9?
Here are the items that are included inside the box of ESL 9:
Floorstanding hybrid electrostatic loudspeakerAC power adapter (w/ attached 10-feet DC cord)Grille4 Spike FeetUsers ManualProduct Registration Card
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 |
400 watts
vs
250 watts
|
Handle more power from your amplifier |
 Sensitivity |
90 dB
vs
88 dB
|
Play louder with same amount of amplification power |
 Woofer Size |
8 inches
vs
6.5 inches
|
Larger woofer |
| Low Frequency Response |
34 Hz
vs
48 Hz
|
Generates deeper bass |
 Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 High Frequency Response |
28k Hz
vs
23k Hz
|
Generates higher frequency |
 Height |
1113mm
vs
1520mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
778cm2 (200x389mm)
vs
1721cm2 (266x647mm)
|
Takes less floor space |
 Price per pair* |
4500USD
vs
7000USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
MartinLogan Masterpiece Classic ESL 9 |
KEF R7 |
| Brand |
MartinLogan |
KEF |
| Speaker Type |
Floor-standing speaker |
Floor-standing speaker |
| Power Range |
20-400 watts |
15-250 watts |
| Sensitivity |
90 dB |
88 dB |
| Impedance |
4 ohms |
8 ohms |
| Impedance |
n/a |
3.2 ohms |
| Frequency Response |
34-23k Hz |
48-28k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
8" |
6.5" |
| Woofer Composition |
high-excursion paper cone |
Hybrid Aluminum |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
9.2 x 44" |
1" |
| Tweeter Type |
curved electrostatic transducer |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
5" |
| Crossover Frequency |
n/a |
400Hz and 2900Hz |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
1520.0mm (59.8") |
1113.0mm (43.8") |
| Width |
266.0mm (10.5") |
200.0mm (7.9") |
| Depth |
647.0mm (25.5") |
389.0mm (15.3") |
| Weight |
35.45kg (78lbs) |
31.40kg (69.1lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Composite |
MDF/Lacquer |
| Available Colors |
Gloss Black |
Black Gloss, White Gloss, Walnut |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
Yes |
Other |
|
|
| Parts Warranty |
5 Years w/ Registration |
5 Years |
| Labor Warranty |
5 Years w/ Registration |
5 Years |