PSI A21-M Monitor Review

[thewas]

For that price

 

[welwynnick]

Phase correction
Directivity control
3-way
Cardioid response
Ruler flat on-axis response
Integrated room correction

I'm not really sticking up for PSI, but it does have phase correction, and the A23 is a 3-way (with an interesting dome mid).
I don't think it's really missing anything, it's just that Genelec, Neumann and Ascilab etc are better.

 

[LeonidK]

Having PSI's expertise about LF solutions (like the AVAA gear, which is pretty nerdy) but insisting of making all-analog monitors is kind of interesting.

Their monitor range goes way back, the active bass traps are much newer.

 

[pieterv1]

I heard the smaller a14m in Singapore with the amphion one15. I preferred the a14m and thought it a good speaker. The colour is really exactly how it looks online.Its got a kinda 80's pearl sport car feel to it, I kinda like it.

Totally

 

[Tovarich007]

I don't care about the color. Bordeaux, black or white are OK for me.

I'm happy that Amir has appreciated much these speakers and he hasn't stop his test review to pure measurments, which are good but not exceptionnal, but, once again, unless you don't push the limits of speakers, some weaknesses in measures are not problematic.

I definitely LOVED the PSI a17 et A23-M that I listened about two years ago at JL Ohl booth near Paris and very close from my home. Performance wise, Genelec and Neumann are superior to some extent, but PSI are still good. I was not bothered at all by any audible distorsion in the bass and mids. I have not been bothered too by the narrow sweet spot and small directivity errors.

By the way, JL Ohl is a super competent acoustician, audio d)stributor and installator in the pro audio world. His place is one of very rare where you can compare lot of gears, and speakers like PSI, Genelec and Neumann, with an appointment prepared in advance of course.
That's not an ad from me, I didn't buy anything from him, I don't have the money. But I value competent and nice peole like JL Ohl, that's all..

All analog is simplicity and PSI speakers can be easily serviced in their factory in the french speaking part of Switzerland.
The absence of DSP can be easily replaced by an external digital EQ and calibration. So the choice of all analog circuitry and filtering is still fine (though I admit that the latency of the latest generation of DSP is very low and not anymore a real problem for 90% of the audio works).

My only concern about PSI is their high price of course, but when you really love, you don't count. Anyway, their other conservative concurrent ATC is more expensive and not better. So for people, including pros, who can afford such high priced speakers and value tradition and easiness of service, PSI remains a good choice.
If this speaker brand stays so much appreciated by numerous studios and musicians, especially in the classical music field, there should be some good reasons.

 

[Tovarich007]

P.S. : in Europe, PSI is known mainly for their speakers and not for their bass managing device.
This small company was 30 years ago the maker of Studer monitors before Studer was bought by the Harman group and stop Studer monitors production.
the PSIs are the decendants of the old and already very good Studer monitors, improved slowly. I think the model reviewed by Amir is the fifth or fourth generatiion.

 

[pierre]

Here is my take on the EQ.
Please report your findings, positive or negative!


Give a ton of Biquad but could not get any better.

Score EQ LW: 6.8
with sub: 8.4

Score EQ Score: 7.1
with sub: 8.7

PSI A21-M APO LW EQ 96000Hz
March132026-183914

Preamp: -1.50 dB

Filter 1: ON HPQ Fc 32.8 Hz Gain 0.00 dB Q 1.30
Filter 2: ON PK Fc 50.0 Hz Gain -3.35 dB Q 1.93
Filter 3: ON PK Fc 641.2 Hz Gain -1.67 dB Q 1.57
Filter 4: ON PK Fc 943.1 Hz Gain -3.65 dB Q 6.00
Filter 5: ON PK Fc 1252.2 Hz Gain -2.56 dB Q 5.95
Filter 6: ON PK Fc 1101.0 Hz Gain 2.11 dB Q 1.57
Filter 7: ON PK Fc 2015.8 Hz Gain 1.86 dB Q 2.72
Filter 8: ON PK Fc 2378.4 Hz Gain -2.10 dB Q 1.61
Filter 9: ON PK Fc 3880.5 Hz Gain 0.88 dB Q 4.29
Filter 10: ON PK Fc 6186.6 Hz Gain -0.79 dB Q 3.89
Filter 11: ON PK Fc 12480.2 Hz Gain 2.48 dB Q 0.99
Filter 12: ON PK Fc 13094.2 Hz Gain -2.95 dB Q 3.86

PSI A21-M APO Score EQ 96000Hz
March132026-183915

Preamp: -1.50 dB

Filter 1: ON HPQ Fc 32.8 Hz Gain 0.00 dB Q 1.30
Filter 2: ON PK Fc 50.0 Hz Gain -3.27 dB Q 1.92
Filter 3: ON PK Fc 609.3 Hz Gain -1.42 dB Q 1.41
Filter 4: ON PK Fc 960.0 Hz Gain -3.65 dB Q 5.52
Filter 5: ON PK Fc 1228.5 Hz Gain -2.49 dB Q 4.44
Filter 6: ON PK Fc 1067.6 Hz Gain 3.06 dB Q 3.83
Filter 7: ON PK Fc 1867.8 Hz Gain 1.96 dB Q 2.06
Filter 8: ON PK Fc 2873.2 Hz Gain -2.12 dB Q 1.06
Filter 9: ON PK Fc 3751.8 Hz Gain 1.03 dB Q 4.57
Filter 10: ON PK Fc 6343.4 Hz Gain -0.73 dB Q 6.00
Filter 11: ON PK Fc 12124.2 Hz Gain 2.56 dB Q 2.20
Filter 12: ON PK Fc 12863.9 Hz Gain -3.60 dB Q 4.00

for fun: 12 peqs, max Q==6, max dB=3

Pre-Optimization CEA2034 Score: pref=6.144 | nbd_on=0.305 nbd_pir=0.377 lfx=35Hz sm_pir=0.849
Post-Optimization CEA2034 Score: pref=7.336 | nbd_on=0.179 nbd_pir=0.197 lfx=32Hz sm_pir=0.946
with

+-# -|-Freq (Hz)--|-Q ---------|-Gain (dB)--|-Type-----+
| 1  | 20.15      | 1.306      | +0.000     | HPQ      |
| 2  | 42.40      | 4.223      | +1.387     | PK       |
| 3  | 47.95      | 5.295      | -3.094     | PK       |
| 4  | 86.51      | 4.006      | -1.629     | PK       |
| 5  | 241.97     | 1.791      | -1.481     | PK       |
| 6  | 425.15     | 5.991      | -1.962     | PK       |
| 7  | 555.03     | 5.581      | -1.785     | PK       |
| 8  | 727.75     | 5.660      | +1.502     | PK       |
| 9  | 987.41     | 2.119      | -1.006     | PK       |
| 10 | 3050.59    | 2.926      | -1.897     | PK       |
| 11 | 6734.49    | 6.000      | -1.212     | PK       |
| 12 | 12928.80   | 4.979      | -2.096     | PK       |
+----|------------|------------|------------|----------+

 

[Exprymer]

The painting is indeed one of the best paintings i've seen in a speaker, looking exactly like a premium car paint. The electronics are also turned to 11 in terms of components performance. I would say the price justifies itself there, a little bit.

 

[RandomEar]

It came out last year I think.

Definitely got that early 90's feel, though

(Including the all through-hole PCB design)

 

[dfuller]

Actually quite impressive. The distortion is quite good, staying below 3% at 86dB down to 50hz is quite good for a speaker of this size (not super different to the KH150, which is a far newer design with a lot of engineering tricks).

 

[kharan]

I was curious, this is like the Theseus ship of speakers

A21-M V4

www.psiaudio.swiss

PSI Audio A21-M features tweeter update for absolute fidelity PSI Audio A21-M features tweeter update for absolute fidelity

PSI Audio introduces an updated version of the popular A21-M studio monitor featuring a new tweeter. The new model replaces the previously externally sourced tweeter with one entirely developed and built in the Swiss company’s own manufacture. Outperforming the old version in terms of sound...

www.psiaudio.swiss

A3 and A21 history:​

1996 – PSI A20/2: creation of the first prototype
1998 – Studer A3: the original monitor was born
2003 – PSI Audio A21/2: the original technology inside a PSI Audio cabinet
2006 – PSI Audio A21-M: introduction of polypropylene membrane for better consistency and durability
2009 – PSI Audio A21-M V2: modification of the filters for a wider dispersion
2010 – PSI Audio A21-M V3: introduction of Class G amplification
2015- PSI Audio A21-M V3: new woofer frame and cabinet design
2017 – PSI Audio A21-M V4: more powerful engine, improved crossover filters and output impedance

2022 - PSI Audio introduces an updated version of the popular A21-M studio monitor featuring a new tweeter. The new model replaces the previously externally sourced tweeter with one entirely developed and built in the Swiss company’s own manufacture. Outperforming the old version in terms of sound pressure and distortion, the advanced driver takes the A21-M to the next level, inching ever closer to perfectly natural sound reproduction and imaging accuracy. The A21-M combines the new tweeter with proprietary technologies like AOI, CPR and Class G/H power amplifiers. As the largest two-way loudspeaker in the PSI Audio portfolio, the A21-M marks the transition from nearfield to midfield and operates with astonishing precision in both applications.

 

[Exprymer]

Well, offering AOI and CPR via analog electronics and still keeping noise and THD to a minimum, being competitive even to the newest design from big companies, it's an evidence of the quality of components selection of the electronics board and overall electronics design.

Also the AOI should be talked in higher regard since it's essentially a control system for the loudspeaker, which allows for bigger extension and controlled damping. Having this in a fully analog design is not an easy feature, and it's present since the beggining.

 

[Doenerkunde]

Yeah, lower wage countries. Like he USA and the UK.

Yeah, average wages in Switzerland are one third higher than in the US and twice as high as in the UK. One out of every eight Swiss is a dollar millionaire.

 

[Universal Cereal Bus]

Here, we look for flat on axis response (solid black). The A21 almost gets there, sans some variability from 600 to 1 kHz.

"Sans" means without. Unless I'm mistaken, it seems you mean there IS variability there?

 

[wwenze]

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.

But once you add your room EQ, latency is back

 

[capslock]

Nice, thanks @amirm.

Pics;

View attachment 517276

View attachment 517277



JSmith

That board looks like an 80s Elektor kit. Not an SMD part in sight.

 

[Purité Audio]

I bought some of their smaller A-14M? to try they were ok

 

[Exprymer]

This boost at 1KHz is unusual, perharps an on-axis measurement on the specified acoustic center would be fair, since it's where they use to calibrate it.

 

[Ajax]

Hi Amir,

Many thanks for the review.

Can I ask what would be the SPL level with reference to "I cranked the speaker to as loud as I could tolerate (all testing is in near-field at 1.5 meter or 5 feet)."

Even if you don't have a measurement I would be interested in your best guess.

 

[phoenixdogfan]

Quite pricey for what it is. And there's no orange ring around the woofer.

As alway, a very fine review. Thank you, Amir.