In this review, we will be comparing Gravis I and A120P, two Powered Subwoofer speakers from Sonus faber and JBL. 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 JBL Stage A120P 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 JBL Stage A120P have a single woofer setup however the Sonus faber Gravis I's woofer is 8-inch whereas the JBL Stage A120P features a 12-inch woofer.
Frequency Response
Gravis I has a frequency range of 30-120 Hz whereas A120P has a frequency range of 32-150 Hz. With a minimum frequency of 30Hz, the Gravis I can go slightly deeper then the A120P's min frequency of 32Hz.
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 JBL Stage A120P have Bass reflex type enclosure.
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 JBL Stage A120P'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 JBL Stage A120P has external dimensions of 415.0 x 393.0 x 475.0mm (16-5/16 x 15-7/16 x 18-11/16inch).
JBL Stage A120P is clearly the larger of the two speakers. Its body is 107mm wider, 78mm taller and 135mm 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 JBL Stage A120P is approximately 1866.8cm2 / 289.4inch2. The Gravis I requires 48% less surface area than the A120P 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 JBL Stage A120P weighs 18.68kg / 41.1lbs. This makes the A120P 28% heavier than the Gravis I.
Here is a comparison of how Gravis I and A120P'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 JBL Stage A120P?
Here are the items that come with the A120P:
- Powered subwoofer
- Grille
- 6-feet AC power cord
- 4 Spike feet
- Owners Manual
- Warranty Card
- Important Safety Instructions
 Low Frequency Response |
30 Hz
vs
32 Hz
|
Generates deeper bass |
 Height |
337mm
vs
415mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
972cm2
vs
1866cm2
|
Takes less floor space |
| Woofer Size |
12 inches
vs
8 inches
|
Larger woofer |
 High Frequency Response |
150 Hz
vs
120 Hz
|
Generates higher frequency |
 Price per pair* |
300USD
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.
JBL Stage A120P needs about 92% more floor area. JBL Stage A120P stands 135mm further into the room. JBL Stage A120P is 78mm taller.
| General |
Sonus faber Gravis I |
JBL Stage A120P |
| Brand |
Sonus faber |
JBL |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
150 watts |
250 watts |
| Frequency Response |
30-120 Hz |
32-150 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
150-watt RMS |
250-watt RMS |
| Watts Peak (Max) |
n/a |
500-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
12" |
| Woofer Composition |
Treated Paper |
Polycellulose |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
bottom |
front |
Physical Specs |
|
|
| Height |
337.0mm (13.3") |
415.0mm (16.3") |
| Width |
286.0mm (11.3") |
393.0mm (15.5") |
| Depth |
340.0mm (13.4") |
475.0mm (18.7") |
| Weight |
14.55kg (32lbs) |
18.68kg (41.1lbs) |
| 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 |
1 Year |
| Labor Warranty |
2 Yr/3 Yr registered |
1 Year |
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 32Hz). |
| Amplifier power | B | JBL Stage A120P has the bigger amplifier - 250W against 150W RMS, about 2.2dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | B | JBL Stage A120P 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; JBL Stage A120P 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 JBL Stage A120P 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 58% 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. |
| Warranty | A | Sonus faber Gravis I carries 2 years on parts against 1 years. A subwoofer amplifier works harder than anything else in the system, so this is not a throwaway line. |
| Price | B | JBL Stage A120P costs less - $300 against $999, about 70% less. |
A Sonus faber Gravis I B JBL Stage A120P
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?
Neither runs away with it - they trade advantages. Let your room size and where the box can actually stand settle it. Films or music? If this is mainly a home cinema, JBL Stage A120P 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.