Husband and father of five, Matthias runs his own studio facility and production company in the beautiful hills of Switzerland. He sings, plays keys, percussion, guitars, bass, and sax.

During his career, he produced, recorded and mixed hundreds of albums. Several Platinum, Gold and other awards. Here are some of his international production credits: Take 6, Vinnie Colaiuta, Steve Lukather, Abe Laboriel, Paul Jackson, Mike Landau, Kenny Aronoff, Maud, Brian Doerksen, Tom Lane, Lothar Kosse, John Peña, Simon Phillips, Mike Porcaro, Neil Stubenhaus, Ralf Gustke, just to name a few…


«First of all I have to admit, that I am not affiliated to PSI Audio in any ways.» You might have heard or read this phrase throughout the music industry many times before, especially for equipment tests, such as the one here. In fact, I‘ve had several possibilites to meet the guys behind this little manufacturer, mostly on shows or other occasions. After several years of knowing each other, I took the chance to dive into a long-term testing phase with both the actual A21-M and A17- M models – this, because one of my friends works at PSI Audio now. My initial expectations weren‘t too high – and I didn‘t think about investing in any new speakers for my own needs. But here‘s the story, why I was dead-wrong and why I have changed my mind, literally within minutes…

In my short little review, I don‘t want to go too deep into the tech stuff, since a) I feel way too stupid for such things and b) there are enough very good tests and articles out there who describe my testing objects down to the bones. For all of you gear freaks out there: There‘s a great test in the Sound On Sound Magazine, July 2011 issue ( Plus, there‘s another very interesting review from my friend George Necola about the similar, yet bigger PSI Audio A25-M model (check out: With that said, I will rather focus on my personal impressions as a professional musician, producer and engineer.

In Use

Until starting the test, I was using the good ol‘ Adam S3As as main monitors and a pair of Avantones to check how my mixes would sound on Grandma‘s old faithful, but heavily battered kitchen radio (worst case scenario). Now a bit nervous, I removed my Adams and replaced them with a fresh looking pair of A21-Ms. Working on my own songs just prior to the testing phase, it was the perfect arrival time for these beautiful purple speakers, since I exaclty new my audio material. The following moments can be described in short as mind- blowing, revealing and disturbing at the same time.

My first though with the PSI‘s was: Heck, that‘s razor-sharp! Wow, I can hear how the reverb tail of my snare blends with my mix and – this was the disturbing, but very revealing part – I was able to spot all my mixing mistakes I haven‘t detected so far with my previous material. Shock, period.


After a cup of good Swiss coffee I took the chance and went through all of the songs of an album, where I was close to the finish, but where I still got a few questions and doubts regarding frequencies and stereo imaging. My Adams always felt a little bit tiring, it‘s like being hit by lots of audio food – but you‘re not hungry anymore… And with the little Auratones, there‘s no chance to check the full frequency spectrum from bottom to top. These speakers are good for general levels and the «Grandma touch» as mentioned above.

Now, with the PSIs, all this problems were gone instantly! Byebye! In one short afternoon, I went through all of my songs and fixed all these covert frequency problems like it was a promenade. Sure, the Adams sound more impressive, if you listen to finished material, but hey! – I need a workhorse! Now, listening back on the Adams what I‘ve done on the PSIs: This was the next (positive) shock. Everything felt right, in place. Nicely done, even a day later, even after one or two weeks. For me, this was a new, very revealing moment.

I often thought «man – you‘re getting old»! Yes, I do – and my ears are losing detail – but that fast? With the PSIs, I have the strong feeling, that my ears are still intact, I almost thought that I have received a new pair of ears.


Both the A21-Ms and the M17-Ms are extremely well-crafted, highly precise speakers for the daily use in your studio. The bigger model seems to show a bit more detail, but both speakers have a very even (flat) frequency response, pin- sharp stereo image, yet with a wide sweet spot, even when you put them in a horizontal position as I did (which is not the optimum by default, but it was my personal preference).

The brains behind PSI claim their compensated phase response (CPR) to be the secret weapon of their product line. As a user, I have to agree: Can‘t remember of a more precise nearfield speaker at this moment.

If you are a professional musician, producer and/or mixing/mastering engineer – and if you are not a 100% satisfied with your present speakers, give those PSIs a try. Or even better – run and order a pair for you right away – you won‘t regret. Sure, these beautiful purple beasts are not cheap, but worth every penny. And don‘t forget: They are hand made in Switzerland – no cheap crap from far eastern mass production.

The guys at PSI will be happy to help you, if you contact them. And if you have any further questions to a rather new and happy PSI user, drop me a message – I‘d be more than glad to give you some support.