In this review, we will be comparing Alpha S8 and A120P, two Powered Subwoofer speakers from PSB 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 PSB Alpha S8 and JBL Stage A120P first before getting into our more detailed comparison.
In the following sections, we will get into details in order to better understand how the PSB Alpha S8 and JBL Stage A120P compare and hopefully end up with enough arguments to decide which one of these subwoofers is the better choice for you.
**This post contains affiliate links, and I will be compensated if you make a purchase after clicking through my links. As an Amazon Associate I earn from qualifying purchases.
Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Both PSB Alpha S8and JBL Stage A120P have a single woofer setup however the PSB Alpha S8's woofer is 8-inch whereas the JBL Stage A120P features a 12-inch woofer.
Frequency Response
Alpha S8 has a frequency range of 35-150 Hz whereas A120P has a frequency range of 32-150 Hz. With a minimum frequency of 32Hz, the A120P can go slightly deeper then 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 PSB Alpha S8 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 JBL Stage A120P have Bass reflex type enclosure.
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 PSB Alpha S8's and JBL Stage A120P's external dimensions. 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) 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 100mm wider, 97mm taller and 62mm deeper than PSB Alpha S8.
Below you can see the front view size comparison of PSB Alpha S8 and JBL Stage A120P in scale.
Comparison image of PSB Alpha S8 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 PSB Alpha S8 is approximately 1210.1cm2 / 187.6inch2 and base area of the JBL Stage A120P is approximately 1866.8cm2 / 289.4inch2. The Alpha S8 requires 35% 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 PSB Alpha S8 weighs 9.55kg / 21lbs and the JBL Stage A120P weighs 18.68kg / 41.1lbs. This makes the A120P 96% heavier than the Alpha S8.
Here is a comparison of how Alpha S8 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 PSB Alpha S8?
Here are the items that are included inside the box of Alpha S8:
Powered subwooferGrille5-feet AC power cord4 Rubber feet4 Spike feet4 Hex-nutsQuick Start GuideImportant Safety InstructionsWarranty Information
What's in the Box of JBL Stage A120P?
Here are the items that come with the A120P:
Powered subwooferGrille6-feet AC power cord4 Spike feetOwners ManualWarranty CardImportant Safety Instructions
 Height |
318mm
vs
415mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1210cm2 (293x413mm)
vs
1866cm2 (393x475mm)
|
Takes less floor space |
 Woofer Size |
12 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
32 Hz
vs
35 Hz
|
Generates deeper bass |
 Price per pair* |
300USD
vs
549USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
PSB Alpha S8 |
JBL Stage A120P |
| Brand |
PSB |
JBL |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
150 watts |
250 watts |
| Frequency Response |
35-150 Hz |
32-150 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
150-watt RMS |
250-watt RMS |
| Watts Peak (Max) |
n/a |
500-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
12" |
| Woofer Composition |
Polypropylene |
Polycellulose |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
318.0mm (12.5") |
415.0mm (16.3") |
| Width |
293.0mm (11.5") |
393.0mm (15.5") |
| Depth |
413.0mm (16.3") |
475.0mm (18.7") |
| Weight |
9.55kg (21lbs) |
18.68kg (41.1lbs) |
| Enclosure |
Bass Reflex |
Bass reflex |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
1 Year |
1 Year |
| Labor Warranty |
1 Year |
1 Year |