In this review, we will be comparing Flexus Sub 100 and KUBE 8b, two Powered Subwoofer speakers from Klipsch 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 Klipsch Flexus Sub 100 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 Klipsch Flexus Sub 100and KEF KUBE 8b have a single woofer setup however the Klipsch Flexus Sub 100's woofer is 10-inch whereas the KEF KUBE 8b features a 8-inch woofer.
Frequency Response
Flexus Sub 100 has a frequency range of 26-250 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 26Hz, the Flexus Sub 100 can go significantly deeper on the low side and provide stronger bass compared to the KUBE 8b's min frequency of 34Hz.
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
Both Klipsch Flexus Sub 100 and KEF KUBE 8b have Acoustic Suspension type cabinets. 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.
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 Klipsch Flexus Sub 100's and KEF KUBE 8b's external dimensions. Klipsch Flexus Sub 100 has external dimensions of 340.0 x 335.0 x 349.0mm (13-3/8 x 13-3/16 x 13-3/4inch) 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).
Klipsch Flexus Sub 100 is clearly the larger of the two speakers. Its body is 39mm wider, 46mm taller and 10mm 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.
Klipsch Flexus Sub 100 needs about 17% more floor or shelf area. Klipsch Flexus Sub 100 is 46mm 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 Klipsch Flexus Sub 100 is approximately 1169.2cm2 / 181.2inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The Flexus Sub 100 requires 17% 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 Klipsch Flexus Sub 100 weighs 9.40kg / 20.7lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the KUBE 8b 21% heavier than the Flexus Sub 100.
Here is a comparison of how Flexus Sub 100 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 |
| Low Frequency Response |
26 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
250 Hz
vs
140 Hz
|
Generates higher frequency |
 Price per pair* |
350USD
vs
600USD
|
costs less (*prices may change depending on the seller, location and time) |
 Wireless Operation |
Yes
vs
No
|
Connect your subwoofer to your system wireless |
 Height |
294mm
vs
340mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1003cm2
vs
1169cm2
|
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.
Klipsch Flexus Sub 100 needs about 17% more floor area. Klipsch Flexus Sub 100 is 46mm taller.
| General |
Klipsch Flexus Sub 100 |
KEF KUBE 8b |
| Brand |
Klipsch |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
80 watts |
300 watts |
| Frequency Response |
26-250 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
80-watt RMS |
300-watt RMS |
| Watts Peak (Max) |
160-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
8" |
| Woofer Composition |
Paper |
|
| 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 |
340.0mm (13.4") |
294.0mm (11.6") |
| Width |
335.0mm (13.2") |
296.0mm (11.7") |
| Depth |
349.0mm (13.7") |
339.0mm (13.3") |
| Weight |
9.40kg (20.7lbs) |
11.36kg (25lbs) |
| Enclosure |
Acoustic Suspension |
Acoustic Suspension |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
5 Years |
2 Years |
| Labor Warranty |
5 Years |
2 Years |
Different price classes - KEF KUBE 8b costs roughly 1.7x what Klipsch Flexus Sub 100 does. Before paying it, read the note below about two smaller subwoofers.
| Area | Better | Why |
|---|
| Bass depth | A | Klipsch Flexus Sub 100 goes deeper - 26Hz against 34Hz. A real difference, though most music has little content below 34Hz. |
| Amplifier power | B | KEF KUBE 8b has the bigger amplifier - 300W against 80W RMS, about 5.7dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | A | Klipsch Flexus Sub 100 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 | evenly matched | Both are sealed designs, so they roll off in much the same way. |
| Wireless option | depends | Only Klipsch Flexus Sub 100 offers a wireless link. It decides where the sub can go if you cannot run a cable, and is worth nothing if you can. |
| Cabinet size | depends | KEF KUBE 8b is about 26% 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 | Klipsch Flexus Sub 100 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 | Klipsch Flexus Sub 100 costs less - $350 against $600, about 42% less. |
A Klipsch Flexus Sub 100 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?
Klipsch Flexus Sub 100 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. Two small subwoofers beat one big one in most rooms - a pair evens out the room modes in a way no single box can, whatever its specs. At $350 each, two Klipsch Flexus Sub 100 cost about $700 against $600 for one of the other, which is worth a thought.
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.