In this review, we will be comparing R-121SW and Radius 380, two Powered Subwoofer speakers from Klipsch and 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 Klipsch R-121SW and Monitor Audio Radius 380 first before getting into our more detailed comparison.
In the following sections, we will get into details in order to better understand how the Klipsch R-121SW and Monitor Audio Radius 380 compare and hopefully end up with enough arguments to decide which one of these subwoofers is the better choice for you.
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Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Both Klipsch R-121SWand Monitor Audio Radius 380 have a single woofer setup however the Klipsch R-121SW's woofer is 12-inch whereas the Monitor Audio Radius 380 features a 8-inch woofer.
Frequency Response
R-121SW has a frequency range of 28-120 Hz whereas Radius 380 has a frequency range of 30-120 Hz. With a minimum frequency of 28Hz, the R-121SW can go slightly deeper then 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 Klipsch R-121SW has a Bass Reflex type cabinet. Bass Reflex type subwoofers (aka Ported, Vented or Reflex Port) have enclosures that uses a port, hole or vent cut into the cabinet. Ported designs are generally more efficient than the Sealed designs. On the other hand the Monitor Audio Radius 380 have Passive Radiator type enclosure. 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.
Klipsch R-121SW Port
Physical Specs
Size of a speaker can sometimes become an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Klipsch R-121SW's and Monitor Audio Radius 380's external dimensions. Klipsch R-121SW has external dimensions of 423.0 x 407.0 x 532.0mm ( 16-5/8inch x 16inch x 20-15/16inch ) 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) .
Klipsch R-121SW is clearly the larger of the two speakers. Its body is 116mm wider, 115mm taller and 187mm deeper than Monitor Audio Radius 380.
Below you can see the front view size comparison of Klipsch R-121SW and Monitor Audio Radius 380 in scale.
Comparison image of Klipsch R-121SW 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 Klipsch R-121SW is approximately 2165.2cm2 / 335.6inch2 and base area of the Monitor Audio Radius 380 is approximately 1004.0cm2 / 155.6inch2. The R-121SW requires 116% 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 Klipsch R-121SW weighs 16.00kg / 35.2lbs and the Monitor Audio Radius 380 weighs 10.18kg / 22.4lbs. This makes the R-121SW 57% heavier than the Radius 380.
Here is a comparison of how R-121SW 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 Klipsch R-121SW?
Here are the items that are included inside the box of R-121SW:
Powered subwooferGrille6.5-feet AC power cordUser ManualImportant Safety InstructionsWarranty Information
What's in the Box of Monitor Audio Radius 380?
Here are the items that come with the Radius 380:
Powered sub6-feet AC power cord10.75-feet Mono minijack cableOwners ManualImportant Safety Instructions
 Woofer Size |
12 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
28 Hz
vs
30 Hz
|
Generates deeper bass |
 Price per pair* |
599USD
vs
875USD
|
costs less (*prices may change depending on the seller, location and time) |
 Height |
308mm
vs
423mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1004cm2 (291x345mm)
vs
2165cm2 (407x532mm)
|
Takes less floor space |
| General |
Klipsch Reference R-121SW |
Monitor Audio Radius 380 |
| Brand |
Klipsch |
Monitor Audio |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
200 watts |
200 watts |
| Frequency Response |
28-120 Hz |
30-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
8" |
| Woofer Composition |
Spun-Copper TCP |
C-CAM |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
front |
side |
Physical Specs |
|
|
| Height |
423.0mm (16.7") |
308.0mm (12.1") |
| Width |
407.0mm (16") |
291.0mm (11.5") |
| Depth |
532.0mm (20.9") |
345.0mm (13.6") |
| Weight |
16.00kg (35.2lbs) |
10.18kg (22.4lbs) |
| Enclosure |
Bass Reflex |
Passive Radiator |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
2 Years |
| Labor Warranty |
2 Years |
2 Years |