In this review, we will be comparing KF92 and A120P, two Powered Subwoofer speakers from KEF 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 KEF KF92 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.KEF KF92 and JBL Stage A120P have a totally different setup: the KEF KF92 features 2 x 9-inch drivers whereas the A120P features 1 x 12-inch drivers.
Frequency Response
KF92 has a frequency range of 11-200 Hz whereas A120P has a frequency range of 32-150 Hz. With a minimum frequency of 11Hz, the KF92 can go significantly deeper on the low side and provide stronger bass compared to 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 KEF KF92 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 KEF KF92's and JBL Stage A120P's external dimensions. KEF KF92 has external dimensions of 353.0 x 331.0 x 362.0mm (13-7/8 x 13 x 14-1/4inch) 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 62mm wider, 62mm taller and 113mm deeper than KEF KF92.
Below you can see the front view size comparison of KEF KF92 and JBL Stage A120P in scale.
Comparison image of KEF KF92 and JBL Stage A120P 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 KEF KF92 is approximately 1198.2cm2 / 185.7inch2 and base area of the JBL Stage A120P is approximately 1866.8cm2 / 289.4inch2. The KF92 requires 36% 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 KEF KF92 weighs 20.05kg / 44.1lbs and the JBL Stage A120P weighs 18.68kg / 41.1lbs. This makes the KF92 7% heavier than the A120P.
Here is a comparison of how KF92 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 KEF KF92?
Here are the items that are included inside the box of KF92:
- Powered subwoofer
- 6.5-feet AC power cord
- Speaker-level input block
- User Manual
- Important Safety Information
- Warranty 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
 Number of Woofers |
2
vs
1
|
More woofers |
| Low Frequency Response |
11 Hz
vs
32 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
150 Hz
|
Generates higher frequency |
 Height |
353mm
vs
415mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1198cm2
vs
1866cm2
|
Takes less floor space |
| Woofer Size |
12 inches
vs
9 inches
|
Larger woofer |
 Price per pair* |
300USD
vs
2000USD
|
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 56% more floor area. JBL Stage A120P stands 113mm further into the room. JBL Stage A120P is 62mm taller.
| General |
KEF KF92 |
JBL Stage A120P |
| Brand |
KEF |
JBL |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
1000 watts |
250 watts |
| Frequency Response |
11-200 Hz |
32-150 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
1000-watt RMS |
250-watt RMS |
| Watts Peak (Max) |
n/a |
500-watt RMS |
Drivers |
|
|
| Woofer Quantity |
2 |
1 |
| Woofer Size |
9" |
12" |
| Woofer Composition |
Hybrid aluminum |
Polycellulose |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
353.0mm (13.9") |
415.0mm (16.3") |
| Width |
331.0mm (13") |
393.0mm (15.5") |
| Depth |
362.0mm (14.3") |
475.0mm (18.7") |
| Weight |
20.05kg (44.1lbs) |
18.68kg (41.1lbs) |
| Enclosure |
Acoustic Suspension |
Bass reflex |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
1 Year |
| Labor Warranty |
2 Years |
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 | A | KEF KF92 goes deeper - 11Hz against 32Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | A | KEF KF92 has the bigger amplifier - 1000W against 250W RMS, about 6dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | evenly matched | Near-identical radiating area (2 x 9" against 12"). |
| Enclosure | depends | KEF KF92 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 | KEF KF92 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. |
| Cabinet size | depends | KEF KF92 is about 45% 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 | KEF KF92 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 $2,000, about 85% less. |
A KEF KF92 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?
The usual trade-off: KEF KF92 measures better, JBL Stage A120P costs about 85% less. In a normal room, placement will make a bigger difference than the gap between these two. 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, KEF KF92 is usually the easier one to make sound right. Check your amplifier first: if it has no subwoofer or preamp output, KEF KF92 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.