This is a review and detailed measurements of the PSB Alpha P3 bookshelf, 2-way speaker. It is on kind loan from a member and costs US $249 on Amazon including Prime shipping.
I appreciated the magnetic grill. Taking it off you see an upside down configuration with tweeter on the bottom:
This is a very small speaker by the way. Back panel has combined the small port with binding posts which should reduce manufacturing cost:
I was surprised that the model marking and such was under the unit.
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
I performed over 1000 measurement which resulted in error rate of roughly 1%.
Reference axis for measurements was the center of the tweeter. Grill was taken off.
Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.
PSB Alpha P3 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
I must say, I was very disappointed to see so many issues in the on-axis response. It is uneven and suffers from a number of 'acoustic events.' We can easily see their causes if we measure each driver and port in near-field:
The port and woofer resonances are so loud that they push through the overall response. When running the sweeps for distortion tests, i could easily hear a "zing" as it went on at a distinct frequency.
In addition, this is a very low sensitivity speaker. I had to push the levels to the highest I have tested to get 86 dBSPL out of the speaker. It was 5 to 6 dB more than average.
Directivity is decent for good and bad in the way it creates similar room sound but also with the same faults as on-axis:
Resulting in this predicted in-room response:
There is a clear bass hump as well but depending on the room and your taste, that may be OK.
Distortion graphs show one of the resonances very clearly:
It is a small speaker so can't be expected to do well at 96 dBSPL.
Beamwidth is reasonably good:
Resulting in the same in horizontal directivity:
Vertical is typical of 2-way speakers so point the tweeter at your ears if you can:
Finally, impedance measurement again shows same resonance:
But also low impedance which when combined with low sensitivity, means that you need a very stout amplifier to drive these speakers despite their size.
PSB Alpha P3 Listening Tests
The first impression was not bad and didn't match what the graphs were indicating. Then I realized my ears are heavily plugged up from working in the yard recently so popped them open and realized the harshness of the highs. And a resonance coming through with female vocals just like what I had heard in measurements.
At first, I thought the problem was 1 to 2 kHz. Filtering that out helped but not as much as I thought. I messed with a bunch of stuff until I went after the 3 to 4 kHz one and that made the highs much better:
Notice how I actually increased levels across the board to make the subjective loudness the same. Whenever you filter out different bands you reduce overall volume so it is very important to compensate for that. Otherwise the EQ may sound worse in quick AB testing even though it is doing the right thing.
The dip at 150 Hz is optional. Depending on your room modes, this may or may not be necessary. I went back and forth on it as some tracks sounded better with it or the other way around.
When it was all done, the highs were more pleasing but still not quite right.
As noted in the measurements, I had to really crank up my amplifier to drive these. On one hand they took power well for how little they are. On the other hand, the bass becomes distorted tubby sounding.
Conclusions
I have high expectations from PSB given company/designer's work at NRC and with Dr. Floyd Toole. Alas, none of that was delivered here with response that is very uneven with many indications of the problem areas. I appreciate that they are trying to keep the size and cost down but at the same time, I have a minimum bar of fidelity I like to see and the P3 misses that by fair margin.
Given the fact that my ears are plugged up, I am going to put most emphasis on objective measurements and say that I can't recommend the PSB Alpha P3. Company knows how to do better and needs to do that even in budget class. Competition is strong here with many good options.
NOTE: there is a poll on top where you can rate this speaker as well. You don't have to be an owner to do so.
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
I appreciated the magnetic grill. Taking it off you see an upside down configuration with tweeter on the bottom:
This is a very small speaker by the way. Back panel has combined the small port with binding posts which should reduce manufacturing cost:
I was surprised that the model marking and such was under the unit.
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
I performed over 1000 measurement which resulted in error rate of roughly 1%.
Reference axis for measurements was the center of the tweeter. Grill was taken off.
Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.
PSB Alpha P3 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
I must say, I was very disappointed to see so many issues in the on-axis response. It is uneven and suffers from a number of 'acoustic events.' We can easily see their causes if we measure each driver and port in near-field:
The port and woofer resonances are so loud that they push through the overall response. When running the sweeps for distortion tests, i could easily hear a "zing" as it went on at a distinct frequency.
In addition, this is a very low sensitivity speaker. I had to push the levels to the highest I have tested to get 86 dBSPL out of the speaker. It was 5 to 6 dB more than average.
Directivity is decent for good and bad in the way it creates similar room sound but also with the same faults as on-axis:
Resulting in this predicted in-room response:
There is a clear bass hump as well but depending on the room and your taste, that may be OK.
Distortion graphs show one of the resonances very clearly:
It is a small speaker so can't be expected to do well at 96 dBSPL.
Beamwidth is reasonably good:
Resulting in the same in horizontal directivity:
Vertical is typical of 2-way speakers so point the tweeter at your ears if you can:
Finally, impedance measurement again shows same resonance:
But also low impedance which when combined with low sensitivity, means that you need a very stout amplifier to drive these speakers despite their size.
PSB Alpha P3 Listening Tests
The first impression was not bad and didn't match what the graphs were indicating. Then I realized my ears are heavily plugged up from working in the yard recently so popped them open and realized the harshness of the highs. And a resonance coming through with female vocals just like what I had heard in measurements.
At first, I thought the problem was 1 to 2 kHz. Filtering that out helped but not as much as I thought. I messed with a bunch of stuff until I went after the 3 to 4 kHz one and that made the highs much better:
Notice how I actually increased levels across the board to make the subjective loudness the same. Whenever you filter out different bands you reduce overall volume so it is very important to compensate for that. Otherwise the EQ may sound worse in quick AB testing even though it is doing the right thing.
The dip at 150 Hz is optional. Depending on your room modes, this may or may not be necessary. I went back and forth on it as some tracks sounded better with it or the other way around.
When it was all done, the highs were more pleasing but still not quite right.
As noted in the measurements, I had to really crank up my amplifier to drive these. On one hand they took power well for how little they are. On the other hand, the bass becomes distorted tubby sounding.
Conclusions
I have high expectations from PSB given company/designer's work at NRC and with Dr. Floyd Toole. Alas, none of that was delivered here with response that is very uneven with many indications of the problem areas. I appreciate that they are trying to keep the size and cost down but at the same time, I have a minimum bar of fidelity I like to see and the P3 misses that by fair margin.
Given the fact that my ears are plugged up, I am going to put most emphasis on objective measurements and say that I can't recommend the PSB Alpha P3. Company knows how to do better and needs to do that even in budget class. Competition is strong here with many good options.
NOTE: there is a poll on top where you can rate this speaker as well. You don't have to be an owner to do so.
------------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
