o Passive Mode: Pressing the “M” button has no effect.
o Active Mode: Pressing the “M” button suspends music playback so that the listener can hear external room sounds.
o Active Noise-Cancelling Mode: Pressing the “M” button suspends music playback and uses the noise cancellation system to amplify room sounds.
• Headband frame is made of Polycarbonate and is adjustable via “click fittings.” The frame is collapsible to all the headphones to fit in a relatively compact travel case.
• Ear cups (or as PSB calls them, “Driver enclosures”) are made of ABS plus Polycarbonate.
• Both the headband frame and ear cups feature comfortable, Leatherette-covered pads.
• Comfort Fit Gyro-Suspended Ear Cups/Pads: The M4U 2 ear cup mounting system allows ear cups to swivel vertically and laterally for an optimal fit.
• Detachable, user-replaceable 1.2.-meter signal cables—one configured for monitoring applications and the other for headset capabilities. The headset cable provides a built in mic/remote module compatible with iPhones and Blackberry phones.
• Dual signal cable inputs: The M4U2 allows users to plug the headphone’s stereo signal cable into either the left or right-side ear cup, according to their preference.
• Spare set of Leatherette-covered ear pads.
• Airline adapter.
• 3.5mm mini-jack plug to 6.3mm phone jack plug adapter.
• Two 1.2-meter signal cables with 3.5mm mini-jack plugs on the headphone side.
o “Monitoring” cable, targeted primarily toward audio purists, also provides a 3-conductor 3.5mm mini-jack plug for connecting to personal digital music players, tablets, etc.
o Headset or “remote/mic” cable, targeted toward smartphone users, features a 4-conductor 3.5mm mini-jack plug compatible with iPhones and Blackberry phones.
o Both cables feature the room monitor function switches as mentioned above.
• Cleaning cloth.
• Zipper closure carrying case made of molded EVA.
Let me come right out and say it; PSB’s M4U 2 is hands down the best sounding noise-cancelling headphone I’ve yet heard, and it is the only one that invites side-by-side comparison with today’s best passive $400 headphones, which is saying a mouthful. This statement implies several things.
First, the voicing curve of the M4U 2 is wonderfully smooth, evenly and accurately balanced, and blessed with a judicious touch of bass lift that, as advertised, does convey the sense of hearing a fine loudspeaker in a real-world listening room, complete with “room gain.” Not long ago, I had the privilege of meeting with PSB’s Paul Barton and a small group of journalists for a guided tour of Canada’s National Research Council (NRC) acoustics labs—the very facility where PSB’s speakers and where the M4U 2 headphone went through performance verification tests. During the tour, I had the opportunity to participate in some blind listening tests in the NRC’s IEC-certified listening room, and thus to evaluate the sound of several PSB speakers, plus some competing models. Every time I plug in the M4U 2’s, I’m struck by how similar their voicing is to that of some of PSB’s top loudspeakers such as the Synchrony 1 or the new Imagine T2 floorstanders. If you know how good PSB’s top speakers are, then you’ll appreciate that this is high praise indeed.
Next, let me go further to argue that the M4U 2 can, in subtle but significant ways, outperform even the best of PSB’s speakers. I would say, for example, that the M4U 2 offers a more transparent, detailed, and open sound than most loudspeakers do—a sound that gives the headphone an effortlessly vibrant and engaging quality. I would also point out that the M4U 2’s offer deeply extended, powerful, and yet well-defined bass response, bass that few sensibly priced loudspeakers could ever hope to equal.
But one of the most important differentiators of all is that the M4U 2 is very easy to drive—both in passive and active modes—so that it provides vigorous, expansive dynamics without ever sounding like it is working hard. True, you can get dynamics this good from some speaker systems, but to do so you’ll need good, powerful (and often expensive) amplification and carefully picked speaker cables. But with the M4U 2, the amp and cables are already provided, making a true plug’n’play audiophile headphone.