PSB M4U 8 mkII Headphones with Audiodo Calibration System

About 7 years ago, PSB released the M4U 2 headphones which instantly became my go-to long-haul set of headphones that I took everywhere travelling the world with me. Its unique features including the ability to use the headphones passively (with no battery power) and the option to use any regular off the shelf battery were huge for me as a traveler. Since then, I have owned every version of the M4U series headphones.

Of course, when PSB released their newest unit, the M4U 8 mkII, I was intrigued. Furthermore, as a professional calibrator with professional music production as my previous career, makes me even more intrigued with its Audiodo calibration system.
My initial biggest draw to PSB M4U series was the sturdiness of its design. Nothing is creaky; everything is solid. Unlike virtually all of its competitors, the hinges are made of metal and you can feel and hear a definite click and clunk when they are being moved about. It has a solid feel so you wouldn’t feel that the unit would break during regular use. In fact, my very first M4U headphones were broken only after I accidentally dropped my luggage on it, six years into owning it.

Low End
The low frequencies on the PSB M4U 8 mkII is relatively deep-sounding without any hint of muddy-ness thanks to RoomFeel frequency curve embedded in the headphone. With the amplifiers turned off, the bass still has some impact, with good control that leads to only negligible slightest bit of bleeding. With the amplifiers turned on, however, the bass gets even better without being downright booming, with great control of poise.

These headphones have an astounding midrange that I did not expect. Well, that’s not true, since I own most PSB M4U series headphones. But it is still a good feeling of surprise every time I listen to an M4U series headphones. There might be a shade of midrange compression in there, but it’s barely noticeable unless I look for it; and I think even the most serious listeners may never notice it when they don’t look for it. Overall, the mids have some impressive accuracy that do much to elevate this headphone above its relatively cheap price.

High End
The high end of the frequency range seems to follow the examples set by the low end and the mids: despite some minor flaws, the sound remains one of quality. Despite some intentional rolled-off quality in the extremely high notes, the sound is pretty smooth and pleasant, with some knockout female vocals without zero hint of shrill.
There is a good impression of space and depth to the music, but not exaggeratingly so. Some people may not like it because the imaging is not super-wide. However, what I’m hearing from the headphones is just the right amount of imaging as intended in the sample of songs I tried the headphones on, and to be clear, these are the songs the I personally produced and mixed in my professional studios a couple of decades ago so I truly know what those recordings should sound like.

Active Noise Cancellation
The Active Noise Cancellation feature seems to work very well on the M4U 8 mkII. While not as impressive as the technology on Sony XM1000mkIV, it does offer much less fatigue than the Bose or Sony equivalent. It is something that is truly needed for any long haul usage of Active Noise Cancellation (ANC) headphones. And while there is ample detail in there too, just like any ANC, there is a slight lowering of sonic quality when the ANC is activated.

The Audiodo firmware libraries are integrated onto the Bluetooth chipset of the headphones during the manufacturing process. The patented technology is made up of refined coding and polished algorithms that customize audio to perfectly suit your unique hearing characteristics. This way, the algorithm will be able to create a custom frequency curve based on your actual hearing frequency response.

With a series of test tone generated in the headphones, Audiodo can create a hearing-relative flat response to the listener’s actual hearing capability. The yes / no calibration process were done between 3-5 minutes when I tried it. I did try it multiple times and the end results were repeatable and matched my hearing acuity as shown by my professional hearing test results.

For setup video guide on setting up the M4U 8 mkII and use the Audiodo feature:

has yet improved upon the already amazing M4U series of headphones. This time, it is due to the inclusion of Audiodo calibration system. If you already own the original M4U 8 and you’re already highly satisfied with it, perhaps you don’t need to upgrade it to this mkII version. However, if you want an improvement over something that’s already extremely good, here’s your chance to do so!

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