In this review, we will be comparing Studio 650P and KUBE 8b, two Powered Subwoofer speakers from JBL and KEF. 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 JBL Studio 650P and KEF KUBE 8b 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 JBL Studio 650Pand KEF KUBE 8b have a single woofer setup however the JBL Studio 650P's woofer is 10-inch whereas the KEF KUBE 8b features a 8-inch woofer.
Frequency Response
Studio 650P has a frequency range of 35-150 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 34Hz, the KUBE 8b can go slightly deeper then the Studio 650P's min frequency of 35Hz.
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
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 JBL Studio 650P's and KEF KUBE 8b's external dimensions. JBL Studio 650P has external dimensions of 444.5 x 395.3 x 458.8mm () whereas KEF KUBE 8b has external dimensions of 294.0 x 296.0 x 339.0mm (11-9/16 x 11-5/8 x 13-5/16inch).
JBL Studio 650P is clearly the larger of the two speakers. Its body is 99.3mm wider, 150.5mm taller and 119.8mm deeper than KEF KUBE 8b.
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.
JBL Studio 650P needs about 81% more floor or shelf area. JBL Studio 650P is 120mm deeper, so it stands that much further out from the wall. JBL Studio 650P is 151mm 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 JBL Studio 650P is approximately 1813.6cm2 / 281.1inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The Studio 650P requires 81% more surface area than the KUBE 8b which gives it a small disadvantage 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 JBL Studio 650P weighs 10.43kg / 22.9lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the KUBE 8b 9% heavier than the Studio 650P.
Here is a comparison of how Studio 650P and KUBE 8b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Woofer Size |
10 inches
vs
8 inches
|
Larger woofer |
 High Frequency Response |
150 Hz
vs
140 Hz
|
Generates higher frequency |
 Price per pair* |
400USD
vs
600USD
|
costs less (*prices may change depending on the seller, location and time) |
| Low Frequency Response |
34 Hz
vs
35 Hz
|
Generates deeper bass |
 Height |
294mm
vs
444mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1003cm2
vs
1813cm2
|
Takes less floor space |
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 Studio 650P needs about 81% more floor area. JBL Studio 650P stands 120mm further into the room. JBL Studio 650P is 151mm taller.
| General |
JBL Studio 650P |
KEF KUBE 8b |
| Brand |
JBL |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
35-150 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
250-watt RMS |
300-watt RMS |
| Watts Peak (Max) |
500-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
8" |
| Woofer Composition |
|
|
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
444.5mm (17.5") |
294.0mm (11.6") |
| Width |
395.3mm (15.6") |
296.0mm (11.7") |
| Depth |
458.8mm (18.1") |
339.0mm (13.3") |
| Weight |
10.43kg (22.9lbs) |
11.36kg (25lbs) |
| Enclosure |
|
Acoustic Suspension |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
5 Years |
2 Years |
| Labor Warranty |
5 Years |
2 Years |
A ported subwoofer against a sealed 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 (35Hz vs 34Hz). |
| Amplifier power | evenly matched | Much the same amplifier (250W vs 300W RMS) - under 1dB apart. |
| Driver area | A | JBL Studio 650P moves more air: 10" against 8" is 1.56x the cone area, not the 1.25x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | depends | JBL Studio 650P is ported - a ported box gives more output low down for its size, at the cost of a steeper roll-off below tuning; KEF KUBE 8b is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Cabinet size | depends | KEF KUBE 8b is about 63% 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 | JBL Studio 650P carries 5 years on parts against 2 years. A subwoofer amplifier works harder than anything else in the system, so this is not a throwaway line. |
| Price | A | JBL Studio 650P costs less - $400 against $600, about 33% less. |
A JBL Studio 650P B KEF KUBE 8b
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?
JBL Studio 650P is the easier recommendation: it leads on most of the measured areas and costs less. Take KEF KUBE 8b if one of the "depends" rows describes your room. Films or music? If this is mainly a home cinema, JBL Studio 650P will hit harder for the money; if it is mainly for music in a normal-sized room, KEF KUBE 8b is usually the easier one to make sound right. If placement is the constraint - a corner, behind a sofa, under a desk - KEF KUBE 8b is the one that will actually go there, and a well-placed small subwoofer beats a badly-placed big one every time.
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.