In this review, we will be comparing Abyss 8 and KUBE 8b, two Powered Subwoofer speakers from MartinLogan and KEF. Being Powered subwoofers, they both have built-in amplifiers so you don't need an external power amp or an integrated amp to power them. Let's have a brief look at the main features of MartinLogan Abyss 8 and KEF KUBE 8b first before getting into our more detailed comparison.
The sections below take each area in turn: driver and amplifier, frequency response, physical size and connectivity.
Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.MartinLogan Abyss 8and KEF KUBE 8b have the same driver set up: Both subwoofers have 1 x 8" drivers.
Frequency Response
Abyss 8 has a frequency range of 23-200 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 23Hz, the Abyss 8 can go significantly deeper on the low side and provide stronger bass compared to the KUBE 8b's min frequency of 34Hz.
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 Subwoofer class in our database.
Low Frequency
Subwoofer Speakers
High Frequency
Subwoofer Speakers
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 Abyss 8's and KEF KUBE 8b's external dimensions. MartinLogan Abyss 8 has external dimensions of 342.9 x 357.2 x 395.3mm () whereas KEF KUBE 8b has external dimensions of 294.0 x 296.0 x 339.0mm (11-9/16 x 11-5/8 x 13-5/16inch).
MartinLogan Abyss 8 is clearly the larger of the two speakers. Its body is 61.2mm wider, 48.9mm taller and 56.3mm deeper than KEF KUBE 8b.
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 Abyss 8 needs about 41% more floor or shelf area. MartinLogan Abyss 8 is 56mm deeper, so it stands that much further out from the wall. MartinLogan Abyss 8 is 49mm 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 Abyss 8 is approximately 1412.0cm2 / 218.9inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The Abyss 8 requires 41% more surface area than the KUBE 8b which gives it a small disadvantage on placement in tight spaces.
Weight Comparison The weight of a subwoofer may become an important factor if you need to move and reposition the unit often to find the optimal positioning, also known as 'Subwoofer Crawling'. The MartinLogan Abyss 8 weighs 21.18kg / 46.6lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the Abyss 8 86% heavier than the KUBE 8b.
Here is a comparison of how Abyss 8 and KUBE 8b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Low Frequency Response |
23 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
140 Hz
|
Generates higher frequency |
 Height |
294mm
vs
342mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1003cm2
vs
1412cm2
|
Takes less floor space |
 Price per pair* |
600USD
vs
1400USD
|
costs less (*prices may change depending on the seller, location and time) |
Size, drawn to scale
Both subwoofers 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 floor and pushed back to the same wall, so the bigger one visibly takes more of the room.
MartinLogan Abyss 8 needs about 41% more floor area. MartinLogan Abyss 8 stands 56mm further into the room. MartinLogan Abyss 8 is 49mm taller.
| General |
MartinLogan Abyss 8 |
KEF KUBE 8b |
| Brand |
MartinLogan |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
23-200 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
500-watt RMS |
300-watt RMS |
| Watts Peak (Max) |
1000-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
8" |
| Woofer Composition |
|
|
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
342.9mm (13.5") |
294.0mm (11.6") |
| Width |
357.2mm (14.1") |
296.0mm (11.7") |
| Depth |
395.3mm (15.6") |
339.0mm (13.3") |
| Weight |
21.18kg (46.6lbs) |
11.36kg (25lbs) |
| Enclosure |
|
Acoustic Suspension |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years w/ registration |
2 Years |
| Labor Warranty |
3 Years w/ registration |
2 Years |
A passive radiator subwoofer against a sealed one. That is the most consequential line on this page: it decides how the bass rolls off, how it behaves in a small room, and how much output you get for the size of the box.
| Area | Better | Why |
|---|
| Bass depth | A | MartinLogan Abyss 8 goes deeper - 23Hz against 34Hz. That gap covers the lowest notes of a five-string bass and a concert bass drum. |
| Amplifier power | A | MartinLogan Abyss 8 has the bigger amplifier - 500W against 300W RMS, about 2.2dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | evenly matched | Near-identical radiating area (8" against 8"). |
| Enclosure | depends | MartinLogan Abyss 8 is passive radiator - a passive radiator behaves like a port without the pipe noise, and suits a slim cabinet; KEF KUBE 8b is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Cabinet size | depends | KEF KUBE 8b is about 39% smaller by volume. In a subwoofer that is a real trade rather than a preference: box volume is how you get output low down without a bigger amplifier. |
| Warranty | A | MartinLogan Abyss 8 carries 3 years on parts against 2 years. A subwoofer amplifier works harder than anything else in the system, so this is not a throwaway line. |
| Price | B | KEF KUBE 8b costs less - $600 against $1,400, about 57% less. |
A MartinLogan Abyss 8 B KEF KUBE 8b
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both subwoofers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
The usual trade-off: MartinLogan Abyss 8 measures better, KEF KUBE 8b costs about 57% less. In a normal room, placement will make a bigger difference than the gap between these two. Films or music? If this is mainly a home cinema, MartinLogan Abyss 8 will hit harder for the money; if it is mainly for music in a normal-sized room, KEF KUBE 8b is usually the easier one to make sound right. Two small subwoofers beat one big one in most rooms - a pair evens out the room modes in a way no single box can, whatever its specs. At $600 each, two KEF KUBE 8b cost about $1,200 against $1,400 for one of the other, which is worth a thought.
One thing outweighs everything above: where the subwoofer stands. Room modes can add or remove 10dB or more at a given seat, which is far larger than any difference on this page. Before spending more, try the sub in two or three positions - the crawl test, where you put it in the listening seat and crawl the room to find where the bass sounds best, costs nothing and usually beats an upgrade.