In this review, we will be comparing R-121SW and C-308ASWi, two Powered Subwoofer speakers by 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 Klipsch R-121SW and Klipsch C-308ASWi 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 Klipsch R-121SWand Klipsch C-308ASWi have a single woofer setup however the Klipsch R-121SW's woofer is 12-inch whereas the Klipsch C-308ASWi features a 8-inch woofer.
Frequency Response
R-121SW has a frequency range of 28-120 Hz whereas C-308ASWi has a frequency range of 28-150 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
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 Klipsch C-308ASWi 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
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 Klipsch R-121SW's and Klipsch C-308ASWi'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 Klipsch C-308ASWi has external dimensions of 299.0 x 286.0 x 356.0mm (11-3/4 x 11-1/4 x 14inch).
Klipsch R-121SW is clearly the larger of the two speakers. Its body is 121mm wider, 124mm taller and 176mm deeper than Klipsch C-308ASWi.
Below you can see the front view size comparison of Klipsch R-121SW and Klipsch C-308ASWi in scale.
Comparison image of Klipsch R-121SW and Klipsch C-308ASWi 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 Klipsch C-308ASWi is approximately 1018.2cm2 / 157.8inch2. The R-121SW requires 113% more surface area than the C-308ASWi 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 Klipsch C-308ASWi weighs 12.27kg / 27lbs. This makes the R-121SW 30% heavier than the C-308ASWi.
Here is a comparison of how R-121SW and C-308ASWi'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 subwoofer
- Grille
- 6.5-feet AC power cord
- User Manual
- Important Safety Instructions
- Warranty Information
What's in the Box of Klipsch C-308ASWi?
Here are the items that come with the C-308ASWi:
- Powered subwoofer
- Grille
- 8-feet AC power cord
- User Manual
 Woofer Size |
12 inches
vs
8 inches
|
Larger woofer |
 Price per pair* |
599USD
vs
1299USD
|
costs less (*prices may change depending on the seller, location and time) |
 High Frequency Response |
150 Hz
vs
120 Hz
|
Generates higher frequency |
 Height |
299mm
vs
423mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1018cm2
vs
2165cm2
|
Takes less floor space |
 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.
Klipsch R-121SW needs about 113% more floor area. Klipsch R-121SW stands 176mm further into the room. Klipsch R-121SW is 124mm taller.
| General |
Klipsch Reference R-121SW |
Klipsch C Series C-308ASWi |
| Brand |
Klipsch |
Klipsch |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
200 watts |
300 watts |
| Frequency Response |
28-120 Hz |
28-150 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
8" |
| Woofer Composition |
Spun-Copper TCP |
Cerametallic |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
423.0mm (16.7") |
299.0mm (11.8") |
| Width |
407.0mm (16") |
286.0mm (11.3") |
| Depth |
532.0mm (20.9") |
356.0mm (14") |
| Weight |
16.00kg (35.2lbs) |
12.27kg (27lbs) |
| Enclosure |
Bass Reflex |
Passive Radiator |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
2 Years |
| Labor Warranty |
2 Years |
2 Years |
A ported subwoofer against a passive radiator 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 | evenly matched | Effectively the same reach (28Hz vs 28Hz). |
| Amplifier power | B | Klipsch C-308ASWi 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 | A | Klipsch R-121SW moves more air: 12" against 8" is 2.25x the cone area, not the 1.5x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | depends | Klipsch R-121SW is ported - a ported box gives more output low down for its size, at the cost of a steeper roll-off below tuning; Klipsch C-308ASWi is passive radiator - a passive radiator behaves like a port without the pipe noise, and suits a slim cabinet. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Speaker-level inputs | B | Klipsch C-308ASWi takes a speaker-level connection as well as line level. That is what lets it work with an integrated amplifier or a vintage receiver that has no subwoofer output at all. |
| Wireless option | depends | Only Klipsch C-308ASWi 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. |
| Cabinet size | depends | Klipsch C-308ASWi is about 67% 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 | A | Klipsch R-121SW costs less - $599 against $1,299, about 54% less. |
A Klipsch R-121SW B Klipsch C-308ASWi
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?
Klipsch C-308ASWi is ahead, but on only 1 of the measured areas, and it costs about 117% more. Klipsch R-121SW is the sensible buy unless your room is large enough to need the extra. Check your amplifier first: if it has no subwoofer or preamp output, Klipsch C-308ASWi is the only one of these two you can connect at all. Two small subwoofers beat one big one in most rooms - a pair evens out the room modes in a way no single box can, whatever its specs. At $599 each, two Klipsch R-121SW cost about $1,198 against $1,299 for one of the other, which is worth a thought.
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.