In this review, we will be comparing AMBEO Sub and KUBE 8b, two Powered Subwoofer speakers from Sennheiser 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 Sennheiser AMBEO Sub 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.Sennheiser AMBEO Suband KEF KUBE 8b have the same driver set up: Both subwoofers have 1 x 8" drivers.
Frequency Response
AMBEO Sub has a frequency range of 27-80 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 27Hz, the AMBEO Sub 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 Sennheiser AMBEO Sub's and KEF KUBE 8b's external dimensions. Sennheiser AMBEO Sub has external dimensions of 366.7 x 269.9 x 269.9mm () 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).
Sennheiser AMBEO Sub is 26.1mm narrower and 69.1mm less deeper than KEF KUBE 8b but it is also 72.7mm 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 Sennheiser AMBEO Sub is approximately 728.5cm2 / 112.9inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The AMBEO Sub requires 27% less surface area than the KUBE 8b which gives it a small advantage 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 Sennheiser AMBEO Sub weighs 8.16kg / 18lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the KUBE 8b 39% heavier than the AMBEO Sub.
Here is a comparison of how AMBEO Sub and KUBE 8b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Low Frequency Response |
27 Hz
vs
34 Hz
|
Generates deeper bass |
 Base Surface Area |
728cm2
vs
1003cm2
|
Takes less floor space |
 Price per pair* |
500USD
vs
600USD
|
costs less (*prices may change depending on the seller, location and time) |
 High Frequency Response |
140 Hz
vs
80 Hz
|
Generates higher frequency |
 Height |
294mm
vs
366mm
|
Easier to fit in smaller spaces |
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.
KEF KUBE 8b needs about 38% more floor area. KEF KUBE 8b stands 69mm further into the room. Sennheiser AMBEO Sub is 73mm taller.
| General |
Sennheiser AMBEO Sub |
KEF KUBE 8b |
| Brand |
Sennheiser |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
27-80 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
350-watt RMS |
300-watt RMS |
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 |
366.7mm (14.4") |
294.0mm (11.6") |
| Width |
269.9mm (10.6") |
296.0mm (11.7") |
| Depth |
269.9mm (10.6") |
339.0mm (13.3") |
| Weight |
8.16kg (18lbs) |
11.36kg (25lbs) |
| Enclosure |
|
Acoustic Suspension |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
2 Years |
| Labor Warranty |
2 Years |
2 Years |
No single best subwoofer here. Your room, where the box can physically go, and whether this is mainly for films or mainly for music will settle it long before the specs do.
| Area | Better | Why |
|---|
| Bass depth | A | Sennheiser AMBEO Sub goes deeper - 27Hz against 34Hz. A real difference, though most music has little content below 34Hz. |
| Amplifier power | evenly matched | Much the same amplifier (350W vs 300W RMS) - under 1dB apart. |
| Driver area | evenly matched | Near-identical radiating area (8" against 8"). |
| Enclosure | evenly matched | Both are sealed designs, so they roll off in much the same way. |
| Price | A | Sennheiser AMBEO Sub costs less - $500 against $600, about 17% less. |
A Sennheiser AMBEO Sub 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?
Sennheiser AMBEO Sub has the edge on paper, though not by much. The "depends" rows are more likely to decide this than the score is.
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.