In this review, we will be comparing Gravis I 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 I 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 Iand Klipsch R-121SW have a single woofer setup however the Sonus faber Gravis I's woofer is 8-inch whereas the Klipsch R-121SW features a 12-inch woofer.
Frequency Response
Gravis I has a frequency range of 30-120 Hz whereas R-121SW has a frequency range of 28-120 Hz. With a minimum frequency of 28Hz, the R-121SW can go slightly deeper then the Gravis I'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 Sonus faber Gravis I 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
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 I's and Klipsch R-121SW's external dimensions. Sonus faber Gravis I has external dimensions of 337.0 x 286.0 x 340.0mm (13-1/4inch x 11-1/4inch x 13-3/8inch) 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 121mm wider, 86mm taller and 192mm deeper than Sonus faber Gravis I.
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 I is approximately 972.4cm2 / 150.7inch2 and base area of the Klipsch R-121SW is approximately 2165.2cm2 / 335.6inch2. The Gravis I requires 55% 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 I weighs 14.55kg / 32lbs and the Klipsch R-121SW weighs 16.00kg / 35.2lbs. This makes the R-121SW 10% heavier than the Gravis I.
Here is a comparison of how Gravis I 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 I?
Here are the items that are included inside the box of Gravis I:
- Powered subwoofer
- 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
 Height |
337mm
vs
423mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
972cm2
vs
2165cm2
|
Takes less floor space |
 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
999USD
|
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 123% more floor area. Klipsch R-121SW stands 192mm further into the room. Klipsch R-121SW is 86mm taller.
| General |
Sonus faber Gravis I |
Klipsch Reference R-121SW |
| Brand |
Sonus faber |
Klipsch |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
150 watts |
200 watts |
| Frequency Response |
30-120 Hz |
28-120 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
150-watt RMS |
200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
12" |
| Woofer Composition |
Treated Paper |
Spun-Copper TCP |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
bottom |
front |
Physical Specs |
|
|
| Height |
337.0mm (13.3") |
423.0mm (16.7") |
| Width |
286.0mm (11.3") |
407.0mm (16") |
| Depth |
340.0mm (13.4") |
532.0mm (20.9") |
| Weight |
14.55kg (32lbs) |
16.00kg (35.2lbs) |
| Enclosure |
Acoustic Suspension |
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 sealed 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 | evenly matched | Effectively the same reach (30Hz vs 28Hz). |
| Amplifier power | B | Klipsch R-121SW has the bigger amplifier - 200W against 150W RMS, about 1.2dB 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 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 | Sonus faber Gravis I is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room; 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 I 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 I fires 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 I is about 64% 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 $999, about 40% less. |
A Sonus faber Gravis I 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?
Klipsch R-121SW has the edge on paper, though not by much. The "depends" rows are more likely to decide this than the score is. Films or music? If this is mainly a home cinema, Klipsch R-121SW will hit harder for the money; if it is mainly for music in a normal-sized room, Sonus faber Gravis I is usually the easier one to make sound right. Check your amplifier first: if it has no subwoofer or preamp output, Sonus faber Gravis I is the only one of these two you can connect at all.
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.