This is a review, listening tests, EQ and detailed measurements of the PSI A21-M professional monitor. It was sent to me by the company and costs US $3,155 each.
The Swiss company is much more known for their active low frequency absorbers than speakers. While not looking that unique, the large oval shaped woofer ring, as well as the burgundy color of my review sample sets it apart. As expected, the cabinet is super strong and dense. Back panel shows simplicity in execution:
There is no DSP here. Only analog filtering with old school class AB amplification! The Swiss logo really stands out!
PSI A21-Ms Monitor Measurements
As always, we measure speakers using Klippel NFS and compute the standard, CEA/CTA-2034 family of frequency response and directivity measurements:
Here, we look for flat on axis response (solid black). The A21 almost gets there, sans some variability from 600 to 1 kHz. What is surprising and impressive in this small package is very deep bass extension. We are nearly down to 30 Hz!
The larger woofer beams some before tweeter takes over resulting in some directivity error in crossover region. We see the impact of this in our early window reflection sum:
Note that the model behind this computation is for far field listening. So the impact in near-field will be different. Still, it is something to note as we look at the predicted response:
We see the hit from our directivity error the most. But also some of the wiggles below 1 kHz. All in all though, we are close. And with a slope that it is downward, it should sound warm.
While beam width is not constant, I appreciate it being wider than it typical is in monitors:
This helps with spatial effects assuming side walls are not absorbed. You can see the "fatness" in our normalized graph of the same:
Vertical directivity as usual is quite narrow so stay at tweeter axis:
Distortion is kept quite low at 86 dBSPL, but not 96:
Indeed, I could see the clipping indicator light on at 96 dBSPL with audible distortion and much more so at 101 dBSPL:
I have marked with "O" where you should cross over the speaker if you are going to play it loud. And at any rate, avoid 101 dBSPL as we see a fair bit of rise in distortion well into frequency range.
I made near-field measurements but forgot to do so with the port:
That's probably the reason the waterfall shows resonances not visible above:
Yes, that is a new optimized waterfall graph to make it easier to see what is going on.
Step response shows some irregularities in the woofer:
PSI A21-M Speaker Listening Tests and Equalization
You can look at hundreds of measurements but still be surprised when you start playing back a speaker. Here, the immediate impact was the warm bass that accompanied higher registers, once again proving the value of that region. Frankly, the sound was so good I could have stopped there and called this an excellent speaker subjectively.
Sub-bass was reproduced far more than it should be in this size speaker. However, it was mildly distorted even at lower volume levels. Nice though, it never badly broke up as I cranked the speaker to as loud as I could tolerate (all testing is in near-field at 1.5 meter or 5 feet).
I was curious about the on-axis response and directivity errors so one by one, created filters for them:
The difference was subtle but to my liking. The boost in the 2 kHz region was especially nice and balanced out taking down the region below.
With this EQ, every reference track I had sounded excellent and very enjoyable.
Conclusions
PSI brings some differentiation to the market with simplicity of the architecture and deep bass extension. The latter makes sense given the company's prior focus on high quality bass reproduction in rooms. Lack of DSP means zero latency. The down side, and it is a small one, is inability to make the small corrections I made with EQ. Dial that into your DAQ (or music player in domestic listening) and you have an excellent speaker.
Yes, price is way up there. Speaker is hand made in Switzerland. And is sold through dealers.
I really liked the PSI A21-M. More than I probably should have based on uncorrected measurements. I am going to recommend it.
-----------
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/
The Swiss company is much more known for their active low frequency absorbers than speakers. While not looking that unique, the large oval shaped woofer ring, as well as the burgundy color of my review sample sets it apart. As expected, the cabinet is super strong and dense. Back panel shows simplicity in execution:
There is no DSP here. Only analog filtering with old school class AB amplification! The Swiss logo really stands out!
PSI A21-Ms Monitor Measurements
As always, we measure speakers using Klippel NFS and compute the standard, CEA/CTA-2034 family of frequency response and directivity measurements:
Here, we look for flat on axis response (solid black). The A21 almost gets there, sans some variability from 600 to 1 kHz. What is surprising and impressive in this small package is very deep bass extension. We are nearly down to 30 Hz!
The larger woofer beams some before tweeter takes over resulting in some directivity error in crossover region. We see the impact of this in our early window reflection sum:
Note that the model behind this computation is for far field listening. So the impact in near-field will be different. Still, it is something to note as we look at the predicted response:
We see the hit from our directivity error the most. But also some of the wiggles below 1 kHz. All in all though, we are close. And with a slope that it is downward, it should sound warm.
While beam width is not constant, I appreciate it being wider than it typical is in monitors:
This helps with spatial effects assuming side walls are not absorbed. You can see the "fatness" in our normalized graph of the same:
Vertical directivity as usual is quite narrow so stay at tweeter axis:
Distortion is kept quite low at 86 dBSPL, but not 96:
Indeed, I could see the clipping indicator light on at 96 dBSPL with audible distortion and much more so at 101 dBSPL:
I have marked with "O" where you should cross over the speaker if you are going to play it loud. And at any rate, avoid 101 dBSPL as we see a fair bit of rise in distortion well into frequency range.
I made near-field measurements but forgot to do so with the port:
That's probably the reason the waterfall shows resonances not visible above:
Yes, that is a new optimized waterfall graph to make it easier to see what is going on.
Step response shows some irregularities in the woofer:
PSI A21-M Speaker Listening Tests and Equalization
You can look at hundreds of measurements but still be surprised when you start playing back a speaker. Here, the immediate impact was the warm bass that accompanied higher registers, once again proving the value of that region. Frankly, the sound was so good I could have stopped there and called this an excellent speaker subjectively.
Sub-bass was reproduced far more than it should be in this size speaker. However, it was mildly distorted even at lower volume levels. Nice though, it never badly broke up as I cranked the speaker to as loud as I could tolerate (all testing is in near-field at 1.5 meter or 5 feet).
I was curious about the on-axis response and directivity errors so one by one, created filters for them:
The difference was subtle but to my liking. The boost in the 2 kHz region was especially nice and balanced out taking down the region below.
With this EQ, every reference track I had sounded excellent and very enjoyable.
Conclusions
PSI brings some differentiation to the market with simplicity of the architecture and deep bass extension. The latter makes sense given the company's prior focus on high quality bass reproduction in rooms. Lack of DSP means zero latency. The down side, and it is a small one, is inability to make the small corrections I made with EQ. Dial that into your DAQ (or music player in domestic listening) and you have an excellent speaker.
Yes, price is way up there. Speaker is hand made in Switzerland. And is sold through dealers.
I really liked the PSI A21-M. More than I probably should have based on uncorrected measurements.
I am going to recommend it.-----------
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/
Pre-Optimization CEA2034 Score: pref=6.144 | nbd_on=0.305 nbd_pir=0.377 lfx=35Hz sm_pir=0.849
