In this review, we will be comparing Gravis II and R-121SW, two Powered Subwoofer speakers from Sonus faber 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 Sonus faber Gravis II and Klipsch R-121SW 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 Sonus faber Gravis IIand Klipsch R-121SW have a single woofer setup however the Sonus faber Gravis II's woofer is 10-inch whereas the Klipsch R-121SW features a 12-inch woofer.
Frequency Response
Gravis II has a frequency range of 25-120 Hz whereas R-121SW has a frequency range of 28-120 Hz. With a minimum frequency of 25Hz, the Gravis II can go slightly deeper then 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 Sonus faber Gravis II has a Passive Radiator type cabinet. 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. 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
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 Sonus faber Gravis II's and Klipsch R-121SW's external dimensions. Sonus faber Gravis II has external dimensions of 407.0 x 358.0 x 435.0mm (16inch x 14-1/16inch x 17-1/8inch) 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 clearly the larger of the two speakers. Its body is 49mm wider, 16mm taller and 97mm deeper than Sonus faber Gravis II.
Size, drawn to scale
Both speakers 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 surface and pushed back to the same wall, so the deeper one visibly sticks out further.
Klipsch R-121SW needs about 39% more floor or shelf area. Klipsch R-121SW is 97mm deeper, so it stands that much further out from the wall. Klipsch R-121SW is 16mm taller.
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 Sonus faber Gravis II is approximately 1557.3cm2 / 241.4inch2 and base area of the Klipsch R-121SW is approximately 2165.2cm2 / 335.6inch2. The Gravis II requires 28% less surface area than the R-121SW which gives it a small advantage 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 Sonus faber Gravis II weighs 21.50kg / 47.3lbs and the Klipsch R-121SW weighs 16.00kg / 35.2lbs. This makes the Gravis II 34% heavier than the R-121SW.
Here is a comparison of how Gravis II 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 Sonus faber Gravis II?
Here are the items that are included inside the box of Gravis II:
- Powered subwoofer
- Grille
- 6-feet AC power cord
- 33-feet Speakon cable
- Owners Manual
- Environmental Information
What's in the Box of Klipsch R-121SW?
Here are the items that come with the R-121SW:
- Powered subwoofer
- Grille
- 6.5-feet AC power cord
- User Manual
- Important Safety Instructions
- Warranty Information
 Low Frequency Response |
25 Hz
vs
28 Hz
|
Generates deeper bass |
 Passive Radiator |
2 x 10-inch
vs
None
|
Increases the bass performance |
 Height |
407mm
vs
423mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1557cm2
vs
2165cm2
|
Takes less floor space |
| Woofer Size |
12 inches
vs
10 inches
|
Larger woofer |
 Price per pair* |
599USD
vs
1499USD
|
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.
Klipsch R-121SW needs about 39% more floor area. Klipsch R-121SW stands 97mm further into the room. Klipsch R-121SW is 16mm taller.
| General |
Sonus faber Gravis II |
Klipsch Reference R-121SW |
| Brand |
Sonus faber |
Klipsch |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
350 watts |
200 watts |
| Frequency Response |
25-120 Hz |
28-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
350-watt RMS |
200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
12" |
| Woofer Composition |
Treated Paper |
Spun-Copper TCP |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
407.0mm (16") |
423.0mm (16.7") |
| Width |
358.0mm (14.1") |
407.0mm (16") |
| Depth |
435.0mm (17.1") |
532.0mm (20.9") |
| Weight |
21.50kg (47.3lbs) |
16.00kg (35.2lbs) |
| Enclosure |
Passive Radiator |
Bass Reflex |
| Available Colors |
Piano Black,Matte White |
n/a |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Yr/3 Yr registered |
2 Years |
| Labor Warranty |
2 Yr/3 Yr registered |
2 Years |
A passive radiator subwoofer against a ported 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 | A | Sonus faber Gravis II goes deeper - 25Hz against 28Hz. A real difference, though most music has little content below 28Hz. |
| Amplifier power | A | Sonus faber Gravis II has the bigger amplifier - 350W against 200W RMS, about 2.4dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | B | Klipsch R-121SW moves more air: 12" against 10" is 1.44x the cone area, not the 1.2x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | depends | Sonus faber Gravis II is passive radiator - a passive radiator behaves like a port without the pipe noise, and suits a slim cabinet; 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. 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 | A | Sonus faber Gravis II 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. |
| Driver placement | depends | Sonus faber Gravis II fires front/down and Klipsch R-121SW fires front. A down-firing driver is more forgiving of a grille-less look and of a hard floor; a front-firing one is the safer choice on a thick carpet or a suspended timber floor. |
| Cabinet size | depends | Sonus faber Gravis II is about 31% 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 | Klipsch R-121SW costs less - $599 against $1,499, about 60% less. |
A Sonus faber Gravis II B Klipsch R-121SW
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: Sonus faber Gravis II measures better, Klipsch R-121SW costs about 60% less. In a normal room, placement will make a bigger difference than the gap between these two. Check your amplifier first: if it has no subwoofer or preamp output, Sonus faber Gravis II 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 $1,499 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.