In this review, we will be comparing two different types of speakers by MartinLogan. MartinLogan Motion 4i 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 Motion 4i and MartinLogan 8i first before getting into our more
detailed comparison.
| Key Specs | MartinLogan Motion 4i | MartinLogan 8i |
|---|
| Brand | MartinLogan
United States · founded 1982 | MartinLogan
United States · founded 1982 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1 x 1.4" Folded Motion Ribbon | 1.0 x 1.4" Folded Motion |
|---|
| Woofer | 4" | 2 x 4" poly cone woofers with rigid dust caps |
|---|
| Frequency response | 70-23k Hz | 70-23k Hz |
|---|
| Sensitivity | 90 dB | 89 dB |
|---|
| Impedance | 4 ohms | 4 ohms |
|---|
| Power range | — | 20-180 watts |
|---|
| Weight | 2.72kg / 6lbs | 3.86kg / 8.5lbs |
|---|
| Dimensions (H x W x D) | 12-11/16" x 5-11/16" x 5-11/16"
322.3 x 144.5 x 144.5mm | 5-9/16" x 22-1/8" x 5-1/4"
142.0 x 562.0 x 134.0mm |
|---|
Motion 4i 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
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both Motion 4i and Motion 8i are 2-way speakers.
MartinLogan Motion 4iMartinLogan 8i
Woofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
MartinLogan Motion 4i |
MartinLogan 8i |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1 x 1.4-inch
|
1.0 x 1.4-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 4-inch
|
2 x 4-inch
|
Motion 4i features a 1 x 1.4" Folded Motion Ribbon Tweeter and 1 x 4" Woofer. 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 4i and Motion 8i has exactly the same frequency range of 70-23k Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf 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
Motion 4i and Motion 8i have the same Impedance of 4 ohms but where they differ is the sensitivity levels. Motion 4i sensitivity is rated at 90 dB and the Motion 8i's is at 89 dB. This 1 dB difference makes the MartinLogan Motion 4i a more sensitive speaker compared to MartinLogan 8i, hence will play louder with the same amount of watts.
One thing to keep in mind that the lower impedance speakers, especially the ones that are rated at 4 ohms may put more pressure on the amplifier unit comared to higher impedance speakers especially at high volume levels, so make sure the amp you pair with the Motion 4i and the Motion 4i can provide this impedance level.
Sensitivity
Bookshelf Speakers
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
Motion 4i features Spring post type posts and Motion 8i has a Spring post type posts. None of these speakers feature bi-amping/bi-wiring.
MartinLogan 8i's Spring post terminals
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 Motion 4i's and MartinLogan 8i's external dimensions. MartinLogan Motion 4i has external dimensions of 322.3 x 144.5 x 144.5mm () 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 180.3mm shorter and 10.5mm less deeper than MartinLogan Motion 4i but it is also 417.5mm wider.
Size, drawn to scale
Both speakers and both views share one scale, so everything here is directly comparable. Hover a box for its dimensions.
One scale for both, standing on the same surface and pushed back to the same wall, so the deeper one visibly sticks out further.
MartinLogan 8i needs about 261% more floor or shelf area. MartinLogan Motion 4i is 180mm taller.
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 4i is approximately 208.8cm2 / 32.4inch2 and base area of the MartinLogan 8i is approximately 753.1cm2 / 116.7inch2. The Motion 4i requires 72% 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 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