In this review, we will be comparing Kube 15 MIE and R-121SW, two Powered Subwoofer speakers from KEF and Klipsch. 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 KEF Kube 15 MIE and Klipsch R-121SW first before getting into our more detailed comparison.
In the following sections, we will get into details in order to better understand how the KEF Kube 15 MIE and Klipsch R-121SW 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 KEF Kube 15 MIEand Klipsch R-121SW have a single woofer setup however the KEF Kube 15 MIE's woofer is 15-inch whereas the Klipsch R-121SW features a 12-inch woofer.
Frequency Response
Kube 15 MIE has a frequency range of 20-140 Hz whereas R-121SW has a frequency range of 28-120 Hz. With a minimum frequency of 20Hz, the Kube 15 MIE can go significantly deeper on the low side and provide stronger bass compared to the R-121SW's min frequency of 28Hz.
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 KEF Kube 15 MIE has a Acoustic Suspension type cabinet. 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. On the other hand the Klipsch R-121SW have Bass Reflex type enclosure. 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.
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 KEF Kube 15 MIE's and Klipsch R-121SW's external dimensions. KEF Kube 15 MIE has external dimensions of 519 x 500 x 515 mm ( 20.4 x 19.7 x 20.3 in) whereas Klipsch R-121SW has external dimensions of 423.0 x 407.0 x 532.0mm ( 16-5/8inch x 16inch x 20-15/16inch ) .
Klipsch R-121SW is 93mm narrower and 96mm shorter than KEF Kube 15 MIE but it is also 17mm deeper.
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 KEF Kube 15 MIE is approximately 2575.0cm2 / 399.1inch2 and base area of the Klipsch R-121SW is approximately 2165.2cm2 / 335.6inch2. The Kube 15 MIE requires 19% more surface area than the R-121SW 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 KEF Kube 15 MIE weighs 27.50kg / 60.5lbs and the Klipsch R-121SW weighs 16.00kg / 35.2lbs. This makes the Kube 15 MIE 72% heavier than the R-121SW.
Here is a comparison of how Kube 15 MIE and R-121SW's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
What's in the Box of KEF Kube 15 MIE?
Here are the items that are included inside the box of Kube 15 MIE:
Kube 15 MIE subwoofer Power cord Euroblock speaker level connector User manual and warranty information
What's in the Box of Klipsch R-121SW?
Here are the items that come with the R-121SW:
Powered subwooferGrille6.5-feet AC power cordUser ManualImportant Safety InstructionsWarranty Information
 Woofer Size |
15 inches
vs
12 inches
|
Larger woofer |
| Low Frequency Response |
20 Hz
vs
28 Hz
|
Generates deeper bass |
 High Frequency Response |
140k Hz
vs
120k Hz
|
Generates higher frequency |
 Wireless Operation |
Optional
vs
No
|
Connect your subwoofer to your system wireless |
 Height |
423mm
vs
519mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
2165cm2
vs
2575cm2
|
Takes less floor space |
 Price per pair* |
599USD
vs
1399USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
KEF Kube 15 MIE |
Klipsch Reference R-121SW |
| Brand |
KEF |
Klipsch |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
300 watts |
200 watts |
| Frequency Response |
20-140 Hz |
28-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
300-watt RMS |
200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
15" |
12" |
| Woofer Composition |
Polypropylene |
Spun-Copper TCP |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
40-140 Hz |
n/a |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
519.0mm (20.4") |
423.0mm (16.7") |
| Width |
500.0mm (19.7") |
407.0mm (16") |
| Depth |
515.0mm (20.3") |
532.0mm (20.9") |
| Weight |
27.50kg (60.5lbs) |
16.00kg (35.2lbs) |
| Enclosure |
Acoustic Suspension |
Bass Reflex |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
2 Years |
| Labor Warranty |
2 Years |
2 Years |