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.
| Key Specs | MartinLogan ESL 9 | KEF R7 |
|---|
| Design | 2-way | 3-way |
|---|
| Uni-Q driver | — | 12th Generation Uni-Q |
|---|
| Tweeter | 9.2 x 44" curved electrostatic transducer | 1" Dome |
|---|
| Midrange | — | 5" |
|---|
| Woofer | 2 x 8" high-excursion paper cone | 2 x 6.5" Hybrid Aluminum |
|---|
| Frequency response | 34-23k Hz | 48-28k Hz |
|---|
| Sensitivity | 90 dB | 88 dB |
|---|
| Impedance | 4 ohms | 8 ohms |
|---|
| Power range | 20-400 watts | 15-250 watts |
|---|
| Weight | 35.45kg / 78lbs | 31.40kg / 69.1lbs |
|---|
| Dimensions (H x W x D) | 59-13/16" x 10-7/16" x 25-7/16"
1520.0 x 266.0 x 647.0mm | 43-13/16" x 8" x 15-5/16"
1113.0 x 200.0 x 389.0mm |
|---|
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:
| Listening Environment* |
MartinLogan ESL 9 |
KEF R7 |
| Near-field |
Are you nuts? |
Bad |
| Small Room |
Poor |
Poor |
| Mid-size Room |
Average |
Average |
| Large Room |
Good |
Good |
| Very Large Room |
Good |
Average |
(* 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.
**This post contains affiliate links, and we will be compensated if you make a purchase after clicking
through our links. As an Amazon Associate I earn from qualifying purchases.
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.
MartinLogan ESL 9KEF R7
TweeterMidrangeWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| 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.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Floor-standing class in our database.
Low Frequency
Floor-standing 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
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. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
ESL 9 can handle a max power of 400 watts RMS, whereas R7 has a max power handling value of 250 watts RMS, 150 watts less than the ESL 9.
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
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
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 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.
Below you can see the front view size comparison of MartinLogan ESL 9 and KEF R7 in scale.
Comparison image of MartinLogan ESL 9 and KEF R7 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 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 loudspeaker
- AC power adapter (w/ attached 10-feet DC cord)
- Grille
- 4 Spike Feet
- Users Manual
- Product Registration Card
What's in the Box of KEF R7?
Here are the items that come with the R7:
- Floorstanding loudspeaker
- Grille
- 2 Foam port plugs
- 4 Outrigger feet
- 4 Spikes
- 4 Protective discs
- 4 Screws
- 4 Washers
- Wrench
- Hex-key
- User Manual
- Warranty 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
vs
1721cm2
|
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 |
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 |
A |
MartinLogan ESL 9 digs deeper - 34Hz against 48Hz. |
| Amplifier needs |
A |
MartinLogan ESL 9 is more sensitive (90dB vs 88dB), so it goes louder on the same amplifier. |
| Amplifier match |
B |
KEF R7 is the easier load at 8 ohms; the other is 4 ohms and wants an amplifier rated for it. |
| Headroom |
A |
MartinLogan ESL 9 takes more power (400W vs 250W) - more in hand in a big room. |
| Size |
depends |
KEF R7 is easier to place; MartinLogan ESL 9 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability |
depends |
MartinLogan ESL 9: bi-amping; KEF R7: bi-amping. |
| Price |
B |
KEF R7 is cheaper - $4,500 against $7,000, about 36% less. |
A MartinLogan ESL 9
B KEF R7
depends neither is better in the abstract - it turns on your room, placement 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?
The usual trade-off: MartinLogan ESL 9 measures better, KEF R7 costs about 36% less. Whether that gap is worth the money is the call only you can make - and in a normal room it is often smaller than the numbers suggest. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 48Hz anyway, which makes the cheaper KEF R7 much easier to justify. Match it to your room: we rate MartinLogan ESL 9 the better fit for a very large room; elsewhere the two are rated the same.
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.