In this review, we will be comparing R-121SW and Alpha S8, two Powered Subwoofer speakers from Klipsch and PSB. 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 PSB Alpha S8 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 PSB Alpha S8 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 PSB Alpha S8 have a single woofer setup however the Klipsch R-121SW's woofer is 12-inch whereas the PSB Alpha S8 features a 8-inch woofer.
Frequency Response
R-121SW has a frequency range of 28-120 Hz whereas Alpha S8 has a frequency range of 35-150 Hz. With a minimum frequency of 28Hz, the R-121SW can go significantly deeper on the low side and provide stronger bass compared to the Alpha S8's min frequency of 35Hz.
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 Klipsch R-121SW and PSB Alpha S8 have Bass Reflex type cabinets. 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 Klipsch R-121SW's and PSB Alpha S8'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 PSB Alpha S8 has external dimensions of 318.0 x 293.0 x 413.0mm ( 12-1/2 x 11-1/2 x 16-1/4inch) .
Klipsch R-121SW is clearly the larger of the two speakers. Its body is 114mm wider, 105mm taller and 119mm deeper than PSB Alpha S8.
Below you can see the front view size comparison of Klipsch R-121SW and PSB Alpha S8 in scale.
Comparison image of Klipsch R-121SW and PSB Alpha S8 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 PSB Alpha S8 is approximately 1210.1cm2 / 187.6inch2. The R-121SW requires 79% more surface area than the Alpha S8 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 PSB Alpha S8 weighs 9.55kg / 21lbs. This makes the R-121SW 68% heavier than the Alpha S8.
Here is a comparison of how R-121SW and Alpha S8'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 PSB Alpha S8?
Here are the items that come with the Alpha S8:
Powered subwooferGrille5-feet AC power cord4 Rubber feet4 Spike feet4 Hex-nutsQuick Start GuideImportant Safety InstructionsWarranty Information
 Woofer Size |
12 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
28 Hz
vs
35 Hz
|
Generates deeper bass |
 High Frequency Response |
150k Hz
vs
120k Hz
|
Generates higher frequency |
 Height |
318mm
vs
423mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1210cm2 (293x413mm)
vs
2165cm2 (407x532mm)
|
Takes less floor space |
 Price per pair* |
549USD
vs
599USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Klipsch Reference R-121SW |
PSB Alpha S8 |
| Brand |
Klipsch |
PSB |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
200 watts |
150 watts |
| Frequency Response |
28-120 Hz |
35-150 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
150-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
8" |
| Woofer Composition |
Spun-Copper TCP |
Polypropylene |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
423.0mm (16.7") |
318.0mm (12.5") |
| Width |
407.0mm (16") |
293.0mm (11.5") |
| Depth |
532.0mm (20.9") |
413.0mm (16.3") |
| Weight |
16.00kg (35.2lbs) |
9.55kg (21lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
1 Year |
| Labor Warranty |
2 Years |
1 Year |