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MartinLogan 15i vs MartinLogan 8i Comparison

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MartinLogan 15i

Passive Bookshelf | 60-25k Hz

MartinLogan Motion 15i
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MartinLogan 8i

Passive Center Channel | 70-23k Hz

MartinLogan Motion 8i
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MartinLogan 15i MartinLogan 15i
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MartinLogan 8i MartinLogan 8i
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MartinLogan 15i
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MartinLogan 8i
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MartinLogan 15i vs MartinLogan 8i Speaker Comparison

In this review, we will be comparing two different type of speakers by MartinLogan. MartinLogan Motion 15i is a Bookshelf speaker whereas the Motion 8i is a Center Channel speaker.

Let's have a brief look at the main features of MartinLogan 15i and MartinLogan 8i first before getting into our more detailed comparison.

MartinLogan 15i Key Specs

  • 2-way Design
  • 1.0 x 1.4" Folded Motion Tweeter
  • 5.25" Aluminum Woofer
  • 60-25k Hz Frequency Response
  • 92 dB Sensitivity
  • Impedance: 5ohms
  • Power Range:20-200watts
  • Weight:5.40kg
  • Dimensions (H x W x D): 290.0" x 6.8" x 9.4"( 290.0 x 173.0 x 240.0mm )

MartinLogan 8i Key Specs

  • 2-way Design
  • 1.0 x 1.4" Folded Motion Tweeter
  • 2 x 4" poly cone woofers with rigid dust caps Woofer
  • 70-23k Hz Frequency Response
  • 89 dB Sensitivity
  • Impedance: 4ohms
  • Power Range:20-180watts
  • Weight:3.86kg
  • Dimensions (H x W x D): 142.0" x 22-1/8" x 5-1/4"( 142.0 x 562.0 x 134.0mm )

Motion 15i and Motion 8i are members of MartinLogan's Motion series of speakers. Below you can find the loudspeakers from this series.

MartinLogan Motion Series History
Model Body Frequency SensitivityImpedance Woofer
MartinLogan 15i
Bookshelf 60-25k Hz 92 dB5Ω 1 x 5.25"
MartinLogan 35XTi
  
Bookshelf 50-25k Hz 92 dB4Ω 1 x 6.5"
MartinLogan 60XTi
  
Floor-standing 35-25k Hz 94 dB4Ω 2 x 8"
MartinLogan 50XTi
  
Center Channel 50-25k Hz 94 dB4Ω 2 x 6.5"
MartinLogan LX16
  
Bookshelf 60-25k Hz 92 dB5Ω 1 x 5.25"
MartinLogan 40i
  
Floor-standing 40-25k Hz 92 dB4Ω 2 x 6.5"
MartinLogan 20i
  
Floor-standing 46-25k Hz 90 dB4Ω 2 x 5.5"
MartinLogan 30i
  
Center Channel 65-25k Hz 91 dB4Ω 1 x 5.25"
MartinLogan 6i
  
Center Channel 120-23k Hz 89 dB6Ω 2 x 3.5"
MartinLogan 8i
Center Channel 70-23k Hz 89 dB4Ω 2 x 4"

What size room are the MartinLogan 15i and MartinLogan 8i 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 15i MartinLogan 8i
Near-field Poor Poor
Small Room Average Average
Mid-size Room Good Good
Large Room Average Average
Very Large Room Poor Poor

(* 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.)

In the following sections, we will get into more detail in order to better understand how the MartinLogan 15i and MartinLogan 8i 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

Both Motion 15i and Motion 8i are 2-way speakers.

Driver MartinLogan 15i MartinLogan 8i
Driver Setup 2-way 2-way
Tweeter 1.0 x 1.4-inch 1.0 x 1.4-inch
Midrange - -
Woofer 1 x 5.25-inch 2 x 4-inch

Motion 15i 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 Motion 8i features a 1.0 x 1.4" Folded Motion Tweeter and 2 x 4" poly cone woofers with rigid dust caps Woofer .

Frequency Response

Motion 15i has a frequency range of 60-25k Hz whereas Motion 8i has a frequency range of 70-23k Hz. With a minimum frequency of 60Hz, the Motion 15i can go significantly deeper on the low side and provide stronger bass compared to the Motion 8i's min frequency of 70Hz.

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

Motion 15i
Motion 8i
Min
Average
Max
High Frequency

Bookshelf Speakers

MartinLogan 15i
MartinLogan 8i
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

Motion 15i is a 5 ohms speaker compared to the Motion 8i which has a nominal impedance of 4 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 8i can provide this impedance level.

These two speakers also have different sensitivity levels. Motion 15i sensitivity is rated at 92 dB and the Motion 8i's is rated at 89 dB. This 3 dB difference makes the MartinLogan 15i a more sensitive speaker compared to MartinLogan 8i, hence will play louder with the same amount of watts.

Sensitivity

Bookshelf Speakers

Motion 15i
Motion 8i
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.

Motion 15i can handle a max power of 200 watts RMS from the amp the whereas Motion 8i has a max power handling value of 180 watts RMS, 20 watts less than the Motion 15i.

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 15i features Spring post type posts and Motion 8i has a Spring post type posts. None of these speakers feature bi-amping/bi-wiring.

MartinLogan 15i Terminals
MartinLogan 15i's Custom 5-way tool-less binding posts terminals

MartinLogan 8i Terminals
MartinLogan 8i's Spring post terminals

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 15i's and MartinLogan 8i's external dimensions. MartinLogan 15i has external dimensions of 290.0 x 173.0 x 240.0mm ( 11.4 x 6.8 x 9.4inch) whereas MartinLogan 8i has external dimensions of 142.0 x 562.0 x 134.0mm ( 5-9/16 x 22-1/8 x 5-1/4inch) .

MartinLogan 8i is 148mm shorter and 106mm less deeper than MartinLogan 15i but it is also 389mm 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 15i is approximately 415.2cm2 / 64.4inch2 and base area of the MartinLogan 8i is approximately 753.1cm2 / 116.7inch2. The Motion 15i requires 45% less surface area than the Motion 8i which gives it a small advantage on placement in tight spaces.

What's in the Box of MartinLogan 15i?

Here are the items that are included inside the box of Motion 15i:
  • Bookshelf loudspeaker
  • Grille
  • 4 Rubber feet
  • Users Manual
  • Warranty/Registration Information
  • What's in the Box of MartinLogan 8i?

    Here are the items that come with the Motion 8i:
  • LCR loudspeaker
  • Grille
  • 2 Wall-bracket
  • 2 Shoulder bolts
  • 4 Rubber bumpers
  • Cleaning cloth
  • User-feets Manual (En/Fr)
  • Installation template
  • Product Registration Card

  • Reasons to choose MartinLogan Motion 15i over MartinLogan Motion 8i
    Max Input Power 200 watts vs 180 watts Handle more power from your amplifier
    Sensitivity 92 dB vs 89 dB Play louder with same amount of amplification power
    Nominal Impedance 5 ohms vs 4 ohms Less selective with amplifiers
    Woofer Size 5.25 inches vs 4 inches Larger woofer
    Low Frequency Response 60 Hz vs 70 Hz Generates deeper bass
    High Frequency Response 25k Hz vs 23k Hz Generates higher frequency
    Base Surface Area 415cm2 vs 753cm2 Takes less floor space

    Reasons to choose MartinLogan Motion 8i over MartinLogan Motion 15i

    Number of Woofers 2 vs 1 More woofers
    Height 142mm vs 290mm Easier to fit in smaller spaces
    Price per pair* 450USD vs 900USD costs less (*prices may change depending on the seller, location and time)
    MartinLogan 15i vs MartinLogan 8i Specs Table
    Detailed comparison of specifications
    General MartinLogan Motion 15i MartinLogan Motion 8i
    Brand MartinLogan MartinLogan
    Speaker Type Bookshelf speakers Center channel speaker
    Power Range 20-200 watts 20-180 watts
    Sensitivity 92 dB 89 dB
    Impedance 5 ohms 4 ohms
    Frequency Response 60-25k Hz 70-23k Hz
    Drivers
    Woofer Quantity 1 2
    Woofer Size 5.25" 4"
    Woofer Composition Aluminum poly cone woofers with rigid dust caps
    Woofer Surround Material Rubber n/a
    Tweeter Size 1.0 x 1.4" 1.0 x 1.4"
    Tweeter Type Folded Motion Folded Motion
    Aimable Tweeter No No
    Midrange Driver No No
    Crossover Frequency 2700Hz n/a
    Firing Direction rear n/a
    Suggested Break-in Period Allow 72 hours of break-in at 90 dB Allow 72 hours of break-in at 90 dB
    Physical Specs
    Height 290.0mm (11.4") 142.0mm (5.6")
    Width 173.0mm (6.8") 562.0mm (22.1")
    Depth 240.0mm (9.4") 134.0mm (5.3")
    Weight 5.40kg (11.9lbs) 3.86kg (8.5lbs)
    Enclosure Bass Reflex Passive Radiator
    Finish MDF/Lacquer n/a
    Available Colors Gloss Black, Matt White, Red Walnut Gloss Black, Matt White, Red Walnut
    Mounting Bracket No No
    Recommended Stand Height 26-28" n/a
    Grille Yes Yes
    Moisture Resistancy No No
    Connections
    Biamp Inputs No n/a
    Other
    Parts Warranty 5 Years 5 Yrs w/ Registration
    Labor Warranty 5 Years 5 Yrs w/ Registration

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