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MartinLogan ESL 9 vs Klipsch Forte IV Comparison

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MartinLogan ESL 9

Passive Floor-standing | 34-23k Hz

MartinLogan Masterpiece Classic ESL 9
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Klipsch Forte IV

Passive Floor-standing | 38-20k Hz

Klipsch Heritage Forte IV
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MartinLogan ESL 9 MartinLogan ESL 9
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Klipsch Forte IV Klipsch Forte IV
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MartinLogan ESL 9
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Klipsch Forte IV
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MartinLogan ESL 9 vs Klipsch Forte IV Speaker Comparison

In this review, we will be comparing ESL 9 and Forte IV, two Passive Floor-standing speakers from MartinLogan and Klipsch.

Let's have a brief look at the main features of MartinLogan ESL 9 and Klipsch Forte IV first before getting into our more detailed comparison.

MartinLogan ESL 9 Key Specs

  • 2-way Design
  • 9.2 x 44" curved electrostatic transducer Tweeter
  • 2 x 8" high-excursion paper cone Woofer
  • 34-23k Hz Frequency Response
  • 90 dB Sensitivity
  • Impedance: 4ohms
  • Power Range:20-400watts
  • Weight:35.45kg
  • Dimensions (H x W x D): 1520.0" x 10-7/16" x 25-7/16"( 1520.0 x 266.0 x 647.0mm )

Klipsch Forte IV Key Specs

  • 3-way Design
  • 1" horn-loaded Tweeter
  • 1.75" Midrange
  • 12" Fibercomposite Woofer
  • 1.75" Midrange
  • 38-20k Hz Frequency Response
  • 99 dB Sensitivity
  • Impedance: 8ohms
  • Power Range:up to 100watts
  • Weight:32.73kg
  • Dimensions (H x W x D): 909.0" x 16-5/8" x 13"( 909.0 x 423.0 x 331.0mm )

In the following sections, we will get into more detail in order to better understand how the MartinLogan ESL 9 and Klipsch Forte IV 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 ESL 9 is a 2-way design whereas the Forte IV 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 Klipsch Forte IV
Driver Setup 2-way 3-way
Tweeter 9.2 x 44-inch 1-inch
Midrange - 1 x 1.75-inch
Woofer 2 x 8-inch 1 x 12-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 Forte IV features a 1" titanium-diaphragm compression horn-loaded Tweeter , a 1.75" Midrange and 1 x 12" Fibercomposite Woofer .

Frequency Response

ESL 9 has a frequency range of 34-23k Hz whereas Forte IV has a frequency range of 38-20k Hz. With a minimum frequency of 34Hz, the ESL 9 can go slightly deeper then the Forte IV's min frequency of 38Hz.

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

ESL 9
Forte IV
Min
Average
Max
High Frequency

Floor-standing Speakers

MartinLogan ESL 9
Klipsch Forte IV
Min
Average
Max

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 Forte IV 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 Forte IV's is rated at 99 dB. This 9 dB difference makes the Klipsch Forte IV a more sensitive speaker compared to MartinLogan ESL 9, hence will play louder with the same amount of watts.

Sensitivity

Floor-standing Speakers

ESL 9
Forte IV
Min
Average
Max

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 Forte IV has a max power handling value of 100 watts RMS, 300 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 Forte IV features dual binding post speaker terminals for bi-amping or bi-wiring.

MartinLogan ESL 9 Terminals
MartinLogan ESL 9'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 Klipsch Forte IV'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 Klipsch Forte IV has external dimensions of 909.0 x 423.0 x 331.0mm ( 35-3/4 x 16-5/8 x 13inch) .

Klipsch Forte IV is 611mm shorter and 316mm less deeper than MartinLogan ESL 9 but it is also 157mm wider.

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 Klipsch Forte IV is approximately 1400.1cm2 / 217.0inch2. The ESL 9 requires 23% more surface area than the Forte IV 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 Klipsch Forte IV weighs 32.73kg / 72lbs. This makes the ESL 9 8% heavier than the Forte IV.

Here is a comparison of how ESL 9 and Forte IV's weights compare with the average, max and min weights in Passive Floor-standing class.

Weight
All Floor-standing Speakers
MartinLogan ESL 9
Klipsch Forte IV
Min
Average
Max

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 Klipsch Forte IV?

    Here are the items that come with the Forte IV:
  • 2 Floorstanding loudspeakers
  • 2 Grilles
  • 8 Self-adhesive rubber feet
  • Owners Manual
  • Congratulations letter
  • Klipsch brochure

  • Reasons to choose MartinLogan Masterpiece Classic ESL 9 over Klipsch Heritage Forte IV
    Max Input Power 400 watts vs 100 watts Handle more power from your amplifier
    Number of Woofers 2 vs 1 More woofers
    Low Frequency Response 34 Hz vs 38 Hz Generates deeper bass
    High Frequency Response 23k Hz vs 20k Hz Generates higher frequency

    Reasons to choose Klipsch Heritage Forte IV over MartinLogan Masterpiece Classic ESL 9

    Driver Setup 3-way vs 2-way Have a dedicated mid-range driver
    Sensitivity 99 dB vs 90 dB Play louder with same amount of amplification power
    Nominal Impedance 8 ohms vs 4 ohms Less selective with amplifiers
    Woofer Size 12 inches vs 8 inches Larger woofer
    Passive Radiator rear-firing 15-inch vs None Increases the bass performance
    Height 909mm vs 1520mm Easier to fit in smaller spaces
    Base Surface Area 1400cm2 vs 1721cm2 Takes less floor space
    Price per pair* 4998USD vs 7000USD costs less (*prices may change depending on the seller, location and time)
    MartinLogan ESL 9 vs Klipsch Forte IV Specs Table
    Detailed comparison of specifications
    General MartinLogan Masterpiece Classic ESL 9 Klipsch Heritage Forte IV
    Brand MartinLogan Klipsch
    Speaker Type Floor-standing speaker Floor-standing speaker
    Power Range 20-400 watts up to 100 watts
    Sensitivity 90 dB 99 dB
    Impedance 4 ohms 8 ohms
    Frequency Response 34-23k Hz 38-20k Hz
    Drivers
    Woofer Quantity 2 1
    Woofer Size 8" 12"
    Woofer Composition high-excursion paper cone Fibercomposite
    Woofer Surround Material Rubber Rubber
    Tweeter Size 9.2 x 44" 1"
    Tweeter Type curved electrostatic transducer horn-loaded
    Aimable Tweeter No No
    Midrange Driver No 1.75"
    Firing Direction n/a rear
    Physical Specs
    Height 1520.0mm (59.8") 909.0mm (35.8")
    Width 266.0mm (10.5") 423.0mm (16.7")
    Depth 647.0mm (25.5") 331.0mm (13")
    Weight 35.45kg (78lbs) 32.73kg (72lbs)
    Enclosure Bass Reflex Passive Radiator
    Finish Composite MDF/Wood veneer
    Available Colors Gloss Black Black
    Grille Yes Yes
    Moisture Resistancy No No
    Connections
    Biamp Inputs Yes Yes
    Other
    Parts Warranty 5 Years w/ Registration 10 Years
    Labor Warranty 5 Years w/ Registration 10 Years

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