PSI A21-M Monitor Review

[Purité Audio]

Contemporary actives have a ‘low latency’ option, I was thinking more of the ‘digital is the devil’s handmaiden’ crowd.
Keith

 

[Rzezniq]

The price is a bit of a joke. I can't see anything that would justify it.

 

[MrBlueSky4470]

What do you expect to see for $3000 and what's missing here in your opinion?

 

[Sokel]

The price is a bit of a joke. I can't see anything that would justify it.

Swiss are... Swiss.

They fact that they have the cashiers at the back of their open super markets (so can just pick something and go, no one will stop you) tells a lot about their relationship with money and decent wages.

Trying to justify price points comparing them with lower-wage countries does not work.

 

[Purité Audio]

Another £3k for a start,

PSI Audio A21-M - Red (Pair)

The PSI Audio A21-M, Red (Pair) high power near / mid-field precision monitor covers a broad frequency spectrum, allowing the user to be in full control of their audio production. Its unique and highly optimised assets make it perfect for near, mid-field and surround sound applications where...

kmraudio.com

Keith

 

[Azrael]

I made near-field measurements but forgot to do so with the port

Would you have the opportunity to make up for that? It seems that a little brainpower has gone into the port contour after all:

 

[Matias]

I voted great, measurements are super nice regardless of price, which we all agree is not a good value.

 

[goat76]

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.

As you say, the lack of built-in DSP often means low latency, which is very important in audio production. And as this speaker is meant to be used in a music studio, there is hardly a lack of EQ capabilities in such environment anyway.

 

[respice finem]

not really.

people buying this are likely into Swiss-made, or the look, or both. With them objectively better and cheaper do not mean much.

You're probably right. The build quality seems very good, and without the "gunk" all over the PCB.

 

[respice finem]

...Trying to justify price points comparing them with lower-wage countries does not work.

Theoretically it doesn't work. But practically, this is exactly what potential buyers in lower-wage countries will do.
And those in falling net income countries. Together it's almost the whole world...

 

[TheKoC]

Not for me, but still a great product for those not in the "best bang for the buck" market segment. Nothing hand-build in Switzerland will ever by price competitive.

 

[Maiky76]

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

For the score rational your journey starts here
Explanation for the sub score
The following EQs are “anechoic” EQs to get the speaker right before room integration.
If you able to implement these EQs you must add EQ at LF for room integration, that is usually not optional… see hints there.


The raw data with corrected ER and PIR:

Score no EQ: 6.1
With Sub: 7.8

Spinorama with no EQ:

• Rough response
• Directivity errors
• Good LF
• Port or Box internal issues?

Directivity:
Better stay at tweeter height
Horizontally, better toe-in the speakers by 10/15deg and have the axis crossing in front of the listening location, might help dosing the upper range. explanation here

EQ design:
I have generated two EQs. The APO config files are attached.

• The first one, labelled, LW is targeted at making the LW flat
• The second, labelled Score, starts with the first one and adds the score as an optimization variable (here).
• The EQs are designed in the context of regular stereo use i.e. domestic environment, no warranty is provided for a near field use in a studio environment although the LW might be better suited for this purpose.
• One can model the EQ with Vituixcad by using the DSP "Generic" setting with 96000Hz sampling rate.

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

Spinorama EQ LW

Spinorama EQ Score

Zoom PIR-LW-ON

Regression - Tonal

Radar no EQ vs EQ score
No improvements?

The rest of the plots is attached.

 

[amirm]

I don't know how to say, but this is the measurement of KALI LP6V2 from Erin's Audio corner, which costs about 400$ for a new pair in my country.

You are missing 20 Hz worth of extension at the low end. That makes a big difference subjectively.

 

[amirm]

And personally the color is not my style at all.

It comes in two other colors.

 

[welwynnick]

Thanks Amir, I was keen to see this test. I'm probably unusual in that PSI Audio have been on my radar for a while.
Like them, I value phase linearity a lot. They even have a specification for it "± 45 (250 Hz – 20 kHz)", like recent Neumann models. "105 Hz ... 16 kHz; +/- 45°".
PSI are different to Neumann, Genelec, Kef, GRIMM etc because the signal processing / correction is analogue.
HOWEVER, their claimed SNR varies from 95 to 103 dB across the model range, which is disappointing.
Phase compensation inevitably adds latency, so their claim for low latency is misleading.
Finally, your step response test shows that PSI haven't been as successful at getting both amplitude and phase response linear as Neumann.

 

[moleman]

I'm grateful for the objective review! I've always wondered how these would measure.
I demod a pair of these last year at my place after seeing that Rob Swire (Pendulum - incredible engineer) uses PSI.
They sounded fantastic, but for £5.5k I'm not sure on the value to performance ratio.

 

[martin900]

That's a very antique looking setup, with all separate DIP-opamps. How old is this model, must be 20-30 years?
As well as swiss gear is built, the value for money is gone out the window with their gear. It is made to induce the feel of exclusiveness (Swiss->Banks->Rich->High tech) but the asking prices are in general rather crazy. Just look at the offerings from Nagra or FM Acoustics for example.

Still it's an achievement to get them this flat without DSP. They probably use analog filters.

 

[staticV3]

What do you expect to see for $3000 and what's missing here in your opinion?

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

 

[milosz]

Swiss are... Swiss.

They fact that they have the cashiers at the back of their open super markets (so can just pick something and go, no one will stop you) tells a lot about their relationship with money and decent wages.

Trying to justify price points comparing them with lower-wage countries does not work.

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

 

[amirm]

How old is this model, must be 20-30 years?

It came out last year I think.