In this review, we will be comparing Gravis III and SPL-120, 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 III and Klipsch SPL-120 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 IIIand Klipsch SPL-120 have a single woofer setup however the Sonus faber Gravis III's woofer is 10-inch whereas the Klipsch SPL-120 features a 12-inch woofer.
Frequency Response
Gravis III has a frequency range of 25-120 Hz whereas SPL-120 has a frequency range of 24-125 Hz. With a minimum frequency of 24Hz, the SPL-120 can go slightly deeper then the Gravis III's min frequency of 25Hz.
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 III 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 SPL-120 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.
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 III's and Klipsch SPL-120's external dimensions. Sonus faber Gravis III has external dimensions of 415.0 x 400.0 x 495.0mm (16-5/16 x 15-3/4 x 19-1/2inch) whereas Klipsch SPL-120 has external dimensions of 450.0 x 375.0 x 540.0mm (17-11/16 x 14-3/4 x 21-1/4inch).
Sonus faber Gravis III is 35mm shorter and 45mm less deeper than Klipsch SPL-120 but it is also 25mm wider.
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.
Near-identical footprints. Klipsch SPL-120 is 45mm deeper, so it stands that much further out from the wall. Klipsch SPL-120 is 35mm 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 III is approximately 1980.0cm2 / 306.9inch2 and base area of the Klipsch SPL-120 is approximately 2025.0cm2 / 313.9inch2. The Gravis III requires 2% less surface area than the SPL-120 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 III weighs 26.70kg / 58.7lbs and the Klipsch SPL-120 weighs 20.45kg / 45lbs. This makes the Gravis III 31% heavier than the SPL-120.
Here is a comparison of how Gravis III and SPL-120's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Height |
415mm
vs
450mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1980cm2
vs
2025cm2
|
Takes less floor space |
 Woofer Size |
12 inches
vs
10 inches
|
Larger woofer |
| Low Frequency Response |
24 Hz
vs
25 Hz
|
Generates deeper bass |
 High Frequency Response |
125 Hz
vs
120 Hz
|
Generates higher frequency |
 Price per pair* |
499USD
vs
2700USD
|
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.
Near-identical footprints. Klipsch SPL-120 stands 45mm further into the room. Klipsch SPL-120 is 35mm taller.
| General |
Sonus faber Gravis III |
Klipsch SPL-120 |
| Brand |
Sonus faber |
Klipsch |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
600 watts |
300 watts |
| Frequency Response |
25-120 Hz |
24-125 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
600-watt RMS |
300-watt RMS |
| Watts Peak (Max) |
900-watt RMS |
600-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
12" |
| Woofer Composition |
Honeycomb sandwich |
Cerametallic |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
Continuously adjustable |
n/a |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
415.0mm (16.3") |
450.0mm (17.7") |
| Width |
400.0mm (15.7") |
375.0mm (14.8") |
| Depth |
495.0mm (19.5") |
540.0mm (21.3") |
| Weight |
26.70kg (58.7lbs) |
20.45kg (45lbs) |
| Enclosure |
Acoustic Suspension |
Bass Reflex |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
|
2 Years |
| Labor Warranty |
|
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 (25Hz vs 24Hz). |
| Amplifier power | A | Sonus faber Gravis III has the bigger amplifier - 600W against 300W RMS, about 3dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | B | Klipsch SPL-120 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 III is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room; Klipsch SPL-120 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 III 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. |
| Price | B | Klipsch SPL-120 costs less - $499 against $2,700, about 82% less. |
A Sonus faber Gravis III B Klipsch SPL-120
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?
Sonus faber Gravis III is ahead, but on only 1 of the measured areas, and it costs about 5.4x the price. Klipsch SPL-120 is the sensible buy unless your room is large enough to need the extra. Films or music? If this is mainly a home cinema, Klipsch SPL-120 will hit harder for the money; if it is mainly for music in a normal-sized room, Sonus faber Gravis III is usually the easier one to make sound right. Check your amplifier first: if it has no subwoofer or preamp output, Sonus faber Gravis III 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.