In this review, we will be comparing Alpha P5 and Q150, two Passive Bookshelf speakers from PSB and KEF. Let's have a brief look at the main features
of PSB P5 and KEF Q150 first before getting into our more
detailed comparison.
What size room are the PSB P5 and KEF Q150 speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision factor. Here we have compared their suitability to various sizes of environments considering their size and max power parameters:
In the following sections, we will get into more detail in order to better understand how the PSB P5 and KEF Q150 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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through my links. As an Amazon Associate I earn from qualifying purchases.
Drivers
Both Alpha P5 and Q150 are 2-way speakers.
| Driver |
PSB P5 |
KEF Q150 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
0.75-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 5.25-inch
|
Alpha P5 features a 0.75" anodized aluminum Hard-Dome Tweeter and 1 x 5.25" Polypropylene Woofer with a Crossover frequency at 2500Hz. On the other hand, the Q150 features a 1" vented aluminum Dome Tweeter and 1 x 5.25" Aluminum Woofer with a Crossover frequency at 2500Hz.
Frequency Response
Alpha P5 has a frequency range of 55-21k Hz whereas Q150 has a frequency range of 51-28k Hz. With a minimum frequency of 51Hz, the Q150 can go slightly deeper then the Alpha P5's min frequency of 55Hz.
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 Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
Alpha P5 and Q150 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. Alpha P5 sensitivity is rated at 89 dB and the Q150's is at 86 dB. This 3 dB difference makes the PSB P5 a more sensitive speaker compared to KEF Q150, hence will play louder with the same amount of watts.
Sensitivity
Bookshelf Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. While using an amplifier within this range ensures the nominal performance , inputting a power that is higher than the max wattage can result in a damaged speaker.
Alpha P5 can handle a max power of 100 watts RMS from the amp the whereas Alpha P5 has a max power handling value of 90 watts RMS , 10 watts less than the Q150.
Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker
compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters
such as Impedance, sensitivity and system efficiencies.
Input Type and Bi-Amping / Bi-Wiring
Alpha P5 features Post type posts and Q150 has a Post type posts. None of these speakers feature bi-amping/bi-wiring.
PSB P5's 5-way post terminals
KEF Q150's Post terminals
Cabinet Type and Port Position
Both Alpha P5 and Q150 have rear firing ports. Rear ported speakers generally need more room between the backside of the speaker and the wall compared to sealed and front/bottom ported speakers. Placing the speakers too close to the walls may cause the bass to sound boomy.
If you are limited in space and can't get the speakers away from the backwall, check our Speakers with Front Firing Ports page.
KEF Q150 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 PSB P5's and KEF Q150's external dimensions. PSB P5 has external dimensions of 289.0 x 172.0 x 254.0mm ( 11-3/8 x 6-3/4 x 10inch) whereas KEF Q150 has external dimensions of 303.0 x 180.0 x 278.0mm ( 11.9 x 7.0 x 10.9inch) .
KEF Q150 is clearly the larger of the two speakers. Its body is 8mm wider, 14mm taller and 24mm deeper than PSB P5.
Below you can see the front view size comparison of PSB P5 and KEF Q150 in scale.
Comparison image of PSB P5 and KEF Q150 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 P5 is approximately 436.9cm2 / 67.7inch2 and base area of the KEF Q150 is approximately 500.4cm2 / 77.6inch2. The Alpha P5 requires 13% less surface area than the Q150 which gives it a small advantage on placement in tight spaces.
Here is an another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:
Size Comparison image of PSB P5 and KEF Q150 on a Media Console
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The PSB P5 weighs 4.61kg / 10.1lbs and the KEF Q150 weighs 5.60kg / 12.3lbs. This makes the Q150 21% heavier than the Alpha P5.
Here is a comparison of how Alpha P5 and Q150's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of PSB P5?
Here are the items that are included inside the box of Alpha P5:
2 Bookshelf loudspeakers 2 Grilles 8 Self-adhesive rubber feet Quick Start Guide Warranty Card
What's in the Box of KEF Q150?
Here are the items that come with the Q150:
2 Bookshelf loudspeakers 2 Foam port plugs 8 Self-adhesive rubber feet Owner's Manual Warranty Registration Card
 Sensitivity |
89 dB
vs
86 dB
|
Play louder with same amount of amplification power |
 Minimum Impedance |
4 ohms
vs
3.7 ohms
|
Very low impedance levels puts more pressure on amplifier |
 Height |
289mm
vs
303mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
436cm2 (172x254mm)
vs
500cm2 (180x278mm)
|
Takes less floor space |
 Price per pair* |
449USD
vs
600USD
|
costs less (*prices may change depending on the seller, location and time) |
 Max Input Power |
100 watts
vs
90 watts
|
Handle more power from your amplifier |
 Low Frequency Response |
51 Hz
vs
55 Hz
|
Generates deeper bass |
 High Frequency Response |
28k Hz
vs
21k Hz
|
Generates higher frequency |
| General |
PSB Alpha P5 |
KEF Q150 |
| Brand |
PSB |
KEF |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
10-90 watts |
10-100 watts |
| Sensitivity |
89 dB |
86 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
4 ohms |
3.7 ohms |
| Frequency Response |
55-21k Hz |
51-28k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
5.25" |
| Woofer Composition |
Polypropylene |
Aluminum |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
0.75" |
1" |
| Tweeter Type |
Hard-Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2500Hz |
2500Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
289.0mm (11.4") |
303.0mm (11.9") |
| Width |
172.0mm (6.8") |
180.0mm (7.1") |
| Depth |
254.0mm (10") |
278.0mm (10.9") |
| Weight |
4.61kg (10.1lbs) |
5.60kg (12.3lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF, Wood-grain vinyl |
MDF/Vinyl-wrapped |
| Available Colors |
Walnut,Black Ash |
Black, Walnut, White |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
28-30" |
18-24" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |