In this review, we will be comparing KC62 and Alpha S8, two Powered Subwoofer speakers from KEF and PSB. 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 KC62 and PSB Alpha S8 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 KC62 and PSB Alpha S8 have a totally different setup: the KEF KC62 features 2 x 6.5-inch drivers whereas the Alpha S8 features 1 x 8-inch drivers.
Frequency Response
KC62 has a frequency range of 11-200 Hz whereas Alpha S8 has a frequency range of 35-150 Hz. With a minimum frequency of 11Hz, the KC62 can go significantly deeper on the low side and provide stronger bass compared to the Alpha S8'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
Cabinet Type
The KEF KC62 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 PSB Alpha S8 have Bass Reflex type enclosure. 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.
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 KC62's and PSB Alpha S8's external dimensions. KEF KC62 has external dimensions of 245.0 x 258.0 x 281.0mm (9-5/8inch x 10-1/8inch x 11-1/16inch) whereas PSB Alpha S8 has external dimensions of 318.0 x 293.0 x 413.0mm (12-1/2 x 11-1/2 x 16-1/4inch).
PSB Alpha S8 is clearly the larger of the two speakers. Its body is 35mm wider, 73mm taller and 132mm deeper than KEF KC62.
Below you can see the front view size comparison of KEF KC62 and PSB Alpha S8 in scale.
Comparison image of KEF KC62 and PSB Alpha S8 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 KC62 is approximately 725.0cm2 / 112.4inch2 and base area of the PSB Alpha S8 is approximately 1210.1cm2 / 187.6inch2. The KC62 requires 40% less surface area than the Alpha S8 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 KC62 weighs 14.05kg / 30.9lbs and the PSB Alpha S8 weighs 9.55kg / 21lbs. This makes the KC62 47% heavier than the Alpha S8.
Here is a comparison of how KC62 and Alpha S8'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 KC62?
Here are the items that are included inside the box of KC62:
- 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 PSB Alpha S8?
Here are the items that come with the Alpha S8:
- Powered subwoofer
- Grille
- 5-feet AC power cord
- 4 Rubber feet
- 4 Spike feet
- 4 Hex-nuts
- Quick Start Guide
- Important Safety Instructions
- Warranty Information
 Number of Woofers |
2
vs
1
|
More woofers |
| Low Frequency Response |
11 Hz
vs
35 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
150 Hz
|
Generates higher frequency |
 Height |
245mm
vs
318mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
725cm2
vs
1210cm2
|
Takes less floor space |
 Wireless Operation |
Optional
vs
No
|
Connect your subwoofer to your system wireless |
| Woofer Size |
8 inches
vs
6.5 inches
|
Larger woofer |
 Price per pair* |
549USD
vs
1500USD
|
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.
PSB Alpha S8 needs about 67% more floor area. PSB Alpha S8 stands 132mm further into the room. PSB Alpha S8 is 73mm taller.
| General |
KEF KC62 |
PSB Alpha S8 |
| Brand |
KEF |
PSB |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
1000 watts |
150 watts |
| Frequency Response |
11-200 Hz |
35-150 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
1000-watt RMS |
150-watt RMS |
Drivers |
|
|
| Woofer Quantity |
2 |
1 |
| Woofer Size |
6.5" |
8" |
| Woofer Composition |
|
Polypropylene |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
side |
front |
Physical Specs |
|
|
| Height |
245.0mm (9.6") |
318.0mm (12.5") |
| Width |
258.0mm (10.2") |
293.0mm (11.5") |
| Depth |
281.0mm (11.1") |
413.0mm (16.3") |
| Weight |
14.05kg (30.9lbs) |
9.55kg (21lbs) |
| 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 KC62 goes deeper - 11Hz against 35Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | A | KEF KC62 has the bigger amplifier - 1000W against 150W RMS, about 8.2dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | A | KEF KC62 moves more air: 2 x 6.5" against 8" is 1.32x the cone area, not the 1.15x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | depends | KEF KC62 is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room; PSB Alpha S8 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 KC62 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. |
| Wireless option | depends | Only KEF KC62 offers a wireless link (as a paid option). It decides where the sub can go if you cannot run a cable, and is worth nothing if you can. |
| Driver placement | depends | KEF KC62 fires side and PSB Alpha S8 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 | KEF KC62 is about 54% 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 KC62 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 | PSB Alpha S8 costs less - $549 against $1,500, about 63% less. |
A KEF KC62 B PSB Alpha S8
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 KC62 measures better, PSB Alpha S8 costs about 63% 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, PSB Alpha S8 will hit harder for the money; if it is mainly for music in a normal-sized room, KEF KC62 is usually the easier one to make sound right. Check your amplifier first: if it has no subwoofer or preamp output, KEF KC62 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.