In this review, we will be comparing Radius 380 and KUBE 10b, two Powered Subwoofer speakers from Monitor Audio 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 Monitor Audio Radius 380 and KEF KUBE 10b 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.Both Monitor Audio Radius 380and KEF KUBE 10b have a single woofer setup however the Monitor Audio Radius 380's woofer is 8-inch whereas the KEF KUBE 10b features a 10-inch woofer.
Frequency Response
Radius 380 has a frequency range of 30-120 Hz whereas KUBE 10b has a frequency range of 24-140 Hz. With a minimum frequency of 24Hz, the KUBE 10b can go significantly deeper on the low side and provide stronger bass compared to the Radius 380's min frequency of 30Hz.
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
Cabinet Type
The Monitor Audio Radius 380 has a Passive Radiator type cabinet. Passive Radiator type subwoofers sports a non-powered cone that moves in response to the main woofer to move air out in order to generate stronger bass in a smaller body compared to ported or sealed designs. On the other hand the KEF KUBE 10b have Acoustic Suspension type enclosure. Acoustic Suspension aka Sealed type subwoofers have enclosures that are sealed hence no ports or holes exists on the cabinet. Sealed designs helps to provide more accurate and tight bass responses compared to ported designs.
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 Monitor Audio Radius 380's and KEF KUBE 10b's external dimensions. Monitor Audio Radius 380 has external dimensions of 308.0 x 291.0 x 345.0mm (12-1/8 x 11-7/16 x 13-9/16inch) whereas KEF KUBE 10b has external dimensions of 372.0 x 356.0 x 397.0mm (14-5/8 x 14 x 15-5/8inch).
KEF KUBE 10b is clearly the larger of the two speakers. Its body is 65mm wider, 64mm taller and 52mm deeper than Monitor Audio Radius 380.
Below you can see the front view size comparison of Monitor Audio Radius 380 and KEF KUBE 10b in scale.
Comparison image of Monitor Audio Radius 380 and KEF KUBE 10b Size and External Dimensions
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 Monitor Audio Radius 380 is approximately 1004.0cm2 / 155.6inch2 and base area of the KEF KUBE 10b is approximately 1413.3cm2 / 219.1inch2. The Radius 380 requires 29% less surface area than the KUBE 10b 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 Monitor Audio Radius 380 weighs 10.18kg / 22.4lbs and the KEF KUBE 10b weighs 17.50kg / 38.5lbs. This makes the KUBE 10b 72% heavier than the Radius 380.
Here is a comparison of how Radius 380 and KUBE 10b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
What's in the Box of Monitor Audio Radius 380?
Here are the items that are included inside the box of Radius 380:
- Powered sub
- 6-feet AC power cord
- 10.75-feet Mono minijack cable
- Owners Manual
- Important Safety Instructions
What's in the Box of KEF KUBE 10b?
Here are the items that come with the KUBE 10b:
- Powered subwoofer
- 6.5-feet AC power cord
- Speaker-level input block
- User Manual
- Important Safety Information
- Warranty Information
 Height |
308mm
vs
372mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1004cm2
vs
1413cm2
|
Takes less floor space |
 Woofer Size |
10 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
24 Hz
vs
30 Hz
|
Generates deeper bass |
 High Frequency Response |
140 Hz
vs
120 Hz
|
Generates higher frequency |
 Price per pair* |
750USD
vs
875USD
|
costs less (*prices may change depending on the seller, location and time) |
 Wireless Operation |
Optional
vs
No
|
Connect your subwoofer to your system wireless |
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 10b needs about 41% more floor area. KEF KUBE 10b stands 52mm further into the room. KEF KUBE 10b is 64mm taller.
| General |
Monitor Audio Radius 380 |
KEF KUBE 10b |
| Brand |
Monitor Audio |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
200 watts |
300 watts |
| Frequency Response |
30-120 Hz |
24-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
10" |
| Woofer Composition |
C-CAM |
|
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
side |
front |
Physical Specs |
|
|
| Height |
308.0mm (12.1") |
372.0mm (14.6") |
| Width |
291.0mm (11.5") |
356.0mm (14") |
| Depth |
345.0mm (13.6") |
397.0mm (15.6") |
| Weight |
10.18kg (22.4lbs) |
17.50kg (38.5lbs) |
| Enclosure |
Passive Radiator |
Acoustic Suspension |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
2 Years |
| Labor Warranty |
2 Years |
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 | B | KEF KUBE 10b goes deeper - 24Hz against 30Hz. That gap covers the lowest notes of a five-string bass and a concert bass drum. |
| Amplifier power | B | KEF KUBE 10b has the bigger amplifier - 300W against 200W RMS, about 1.8dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | B | KEF KUBE 10b moves more air: 10" against 8" is 1.56x the cone area, not the 1.25x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | depends | Monitor Audio Radius 380 is passive radiator - a passive radiator behaves like a port without the pipe noise, and suits a slim cabinet; KEF KUBE 10b 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. |
| Wireless option | depends | Only KEF KUBE 10b offers a wireless link (as a paid option). It decides where the sub can go if you cannot run a cable, and is worth nothing if you can. |
| Driver placement | depends | Monitor Audio Radius 380 fires side and KEF KUBE 10b fires front. A down-firing driver is more forgiving of a grille-less look and of a hard floor; a front-firing one is the safer choice on a thick carpet or a suspended timber floor. |
| Cabinet size | depends | Monitor Audio Radius 380 is about 41% 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. |
| Price | B | KEF KUBE 10b costs less - $750 against $875, about 14% less. |
A Monitor Audio Radius 380 B KEF KUBE 10b
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?
KEF KUBE 10b is the easier recommendation: it leads on most of the measured areas and costs less. Take Monitor Audio Radius 380 if one of the "depends" rows describes your room. Films or music? If this is mainly a home cinema, Monitor Audio Radius 380 will hit harder for the money; if it is mainly for music in a normal-sized room, KEF KUBE 10b is usually the easier one to make sound right. If placement is the constraint - a corner, behind a sofa, under a desk - Monitor Audio Radius 380 is the one that will actually go there, and a well-placed small subwoofer beats a badly-placed big one every time.
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.