In this review, we will be comparing Elite ES8 and KUBE 8b, two Powered Subwoofer speakers from Polk Audio 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 Polk Signature Elite ES8 and KEF KUBE 8b first before getting into our more detailed comparison.
In the following sections, we will get into details in order to better understand how the Polk Signature Elite ES8 and KEF KUBE 8b compare and hopefully end up with enough arguments to decide which one of these subwoofers is the better choice for you.
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Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Polk Signature Elite ES8and KEF KUBE 8b have the same driver set up: Both subwoofers have 1 x 8" drivers.
Frequency Response
Elite ES8 has a frequency range of 32-180 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 32Hz, the Elite ES8 can go slightly deeper then 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
The Polk Signature Elite ES8 has a Bass Reflex type cabinet. 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. On the other hand the KEF KUBE 8b have Acoustic Suspension type enclosure. 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.
Polk Signature Elite ES8 Port
Physical Specs
Size of a speaker can sometimes become an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Polk Signature Elite ES8's and KEF KUBE 8b's external dimensions. Polk Signature Elite ES8 has external dimensions of 385.0 x 326.0 x 437.0mm ( 15-1/8inch x 12-13/16inch x 17-3/16inch ) 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) .
Polk Signature Elite ES8 is clearly the larger of the two speakers. Its body is 30mm wider, 91mm taller and 98mm deeper than KEF KUBE 8b.
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 Polk Signature Elite ES8 is approximately 1424.6cm2 / 220.8inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The Elite ES8 requires 42% 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 Polk Signature Elite ES8 weighs 17.73kg / 39lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the Elite ES8 56% heavier than the KUBE 8b.
Here is a comparison of how Elite ES8 and KUBE 8b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
What's in the Box of Polk Signature Elite ES8?
Here are the items that are included inside the box of Elite ES8:
Powered subwooferGrille6-feet AC power cordOwners ManualOnline Product Registration sheet
What's in the Box of KEF KUBE 8b?
Here are the items that come with the KUBE 8b:
Powered subwoofer6.5-feet AC power cordSpeaker-level input blockUser ManualImportant Safety InformationWarranty Information
 Low Frequency Response |
32 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
180k Hz
vs
140k Hz
|
Generates higher frequency |
 Price per pair* |
449USD
vs
600USD
|
costs less (*prices may change depending on the seller, location and time) |
 Height |
294mm
vs
385mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1003cm2 (296x339mm)
vs
1424cm2 (326x437mm)
|
Takes less floor space |
| General |
Polk Signature Elite ES8 |
KEF KUBE 8b |
| Brand |
Polk Audio |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
100 watts |
300 watts |
| Frequency Response |
32-180 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
100-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
8" |
| Woofer Composition |
Mineral-filled polypropylene |
Not given |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
385.0mm (15.2") |
294.0mm (11.6") |
| Width |
326.0mm (12.8") |
296.0mm (11.7") |
| Depth |
437.0mm (17.2") |
339.0mm (13.3") |
| Weight |
17.73kg (39lbs) |
11.36kg (25lbs) |
| Enclosure |
Bass Reflex |
Acoustic Suspension |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years |
2 Years |
| Labor Warranty |
3 Years |
2 Years |