In this review, we will be comparing Radius 390 and Radius 380, two Powered Subwoofer speakers by Monitor Audio. 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 390 and Monitor Audio Radius 380 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 390and Monitor Audio Radius 380 have a single woofer setup however the Monitor Audio Radius 390's woofer is 10-inch whereas the Monitor Audio Radius 380 features a 8-inch woofer.
Frequency Response
Radius 390 and Radius 380 has exactly the same frequency range of 30-120 Hz.
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
Both Monitor Audio Radius 390 and Monitor Audio Radius 380 have Passive Radiator type cabinets. 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.
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 390's and Monitor Audio Radius 380's external dimensions. Monitor Audio Radius 390 has external dimensions of 348.0 x 331.0 x 385.0mm (13-11/16 x 13 x 15-1/8inch) whereas 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).
Monitor Audio Radius 390 is clearly the larger of the two speakers. Its body is 40mm wider, 40mm taller and 40mm deeper than Monitor Audio Radius 380.
Below you can see the front view size comparison of Monitor Audio Radius 390 and Monitor Audio Radius 380 in scale.
Comparison image of Monitor Audio Radius 390 and Monitor Audio Radius 380 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 390 is approximately 1274.4cm2 / 197.5inch2 and base area of the Monitor Audio Radius 380 is approximately 1004.0cm2 / 155.6inch2. The Radius 390 requires 27% more surface area than the Radius 380 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 Monitor Audio Radius 390 weighs 13.77kg / 30.3lbs and the Monitor Audio Radius 380 weighs 10.18kg / 22.4lbs. This makes the Radius 390 35% heavier than the Radius 380.
Here is a comparison of how Radius 390 and Radius 380'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 390?
Here are the items that are included inside the box of Radius 390:
- Powered sub
- 6-feet AC power cord
- 10.75-feet Mono minijack cable
- Owners Manual
- Important Safety Instructions
What's in the Box of Monitor Audio Radius 380?
Here are the items that come with the Radius 380:
- Powered sub
- 6-feet AC power cord
- 10.75-feet Mono minijack cable
- Owners Manual
- Important Safety Instructions
 Woofer Size |
10 inches
vs
8 inches
|
Larger woofer |
 Height |
308mm
vs
348mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1004cm2
vs
1274cm2
|
Takes less floor space |
 Price per pair* |
875USD
vs
1150USD
|
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.
Monitor Audio Radius 390 needs about 27% more floor area. Monitor Audio Radius 390 stands 40mm further into the room. Monitor Audio Radius 390 is 40mm taller.
| General |
Monitor Audio Radius 390 |
Monitor Audio Radius 380 |
| Brand |
Monitor Audio |
Monitor Audio |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
220 watts |
200 watts |
| Frequency Response |
30-120 Hz |
30-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
220-watt RMS |
200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
8" |
| Woofer Composition |
C-CAM |
C-CAM |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
side |
side |
Physical Specs |
|
|
| Height |
348.0mm (13.7") |
308.0mm (12.1") |
| Width |
331.0mm (13") |
291.0mm (11.5") |
| Depth |
385.0mm (15.2") |
345.0mm (13.6") |
| Weight |
13.77kg (30.3lbs) |
10.18kg (22.4lbs) |
| Enclosure |
Passive Radiator |
Passive Radiator |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
2 Years |
| Labor Warranty |
2 Years |
2 Years |
Siblings in Monitor Audio's Radius range - same design thinking, different size. It comes down to your room and your budget.
| Area | Better | Why |
|---|
| Bass depth | evenly matched | Effectively the same reach (30Hz vs 30Hz). |
| Amplifier power | evenly matched | Much the same amplifier (220W vs 200W RMS) - under 1dB apart. |
| Driver area | A | Monitor Audio Radius 390 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 | evenly matched | Both are passive radiator designs, so they roll off in much the same way. |
| Cabinet size | depends | Monitor Audio Radius 380 is about 30% 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 | Monitor Audio Radius 380 costs less - $875 against $1,150, about 24% less. |
A Monitor Audio Radius 390 B Monitor Audio Radius 380
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: Monitor Audio Radius 390 measures better, Monitor Audio Radius 380 costs about 24% less. In a normal room, placement will make a bigger difference than the gap between these two. 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.