Headphone Reviews

Noise Canceling
In testing the noise canceling function of headphones over the years I've found they are often unstable and will act strangely in some circumstances. For example, I've experienced with the Beats Studio headphones situations where I was laying on a pillow or wearing a hoodie over the headphones that they break out into low frequency oscillation at times. I've also noted significant sensitivity to position and seal while measuring some noise cancelers making the measurement of low frequency sound unreliable. This is remarkably common.

Also, almost all noise cancelers that have a passive and/or active without noise canceling modes to sound very different in the various modes. For example, if you looks at the measurements of the Bose QC35 in passive and active modes you can see that they are substantially different...with the passive mode being substantially sub-par in acoustic performance.

I found the PSB M4U 8 in noise canceling mode to be both extremely stable in its performance regardless of position on the ear and nearby acoustic blockages. I also found the M4U 8 to be remarkably similar sounding in all modes—not the same, mind you, but similar enough that performance is acceptable in all modes. I feel this is quite an accomplishment given my previous experience evaluating noise cancelers.

Sound Quality
There are essentially three modes of operation producing three modestly differing sound signatures for the PSB M4U 8: passive; active; and noise canceling. The sonic character of active and noise canceling modes are essentially the same with analog wired, USB wired, and wireless operation.

In my experience, most headphones of this type exhibit widely varying response in the different mode. Though not identical, the PSB M4U 8 sound quality is remarkably similar in all modes of operation compared to most headphones of this type.

Sound Quality in Wired Passive Mode
In wired passive mode the PSB M4U 8 has a fairly warm overall tilt but has a fairly even response otherwise. The most obvious feature is the bass emphasis the bleeds fairly strongly into the mids. Other than being a bit overshadowed by the overly warm lower midrange, response from 600Hz and up is well behaved and relaxed sounding with a modest warm tilt. Though a bit polite, treble response is articulate and natural.

Active Mode (RoomFeel)
In active mode—wether wired analog, USB, or wireless—the headphone's internal DSP circuits instantiate PSB's RoomFeel response. Paul Barton claims their target response is quite like the Harman target, with a bass boost below 150Hz.

In this mode the bass emphasis is limited to below 150Hz and no longer bleeds up into the mids. The bass emphasis is about +7dB above flat, which I find to be 2-3dB too much. Bass quality is good but not great, having a clear character but not particularly well textured.

From 20Hz to about 1kHz response is even and well in line with the Harman target, but response between 1kHz and 4kHz is elevated above target by about 3-5dB. This is the presence region and where our ears are most sensitive. While response at the ear drum has a peak here I find the M4U 8 a bit hotter than neutral making these headphones a little sharp sounding when listening to music.

Response from 4-6kHz may be a little low, but this is sometimes good for a less fatiguing listen, and given the emphasis around 3kHz it's probably good to take the edge off a bit. Treble above this area is nicely on target.

Active Noise Canceling Mode
In this mode noise canceling is added to the picture. Overall response is much like Active Mode response, but a bit of unevenness appears 1-2kHz that causes a bit of high-frequency honkiness...sort of like someone who has a little whistle with their 'S' sounds.

Other than that, the noise canceling mode sounds like the active mode. More importantly, it doesn't have any weird digital artifact sonic character. Switching between the M4U 8 and the Bose QC35, I hear the Bose as the more tonally neutral headphone, but it also has a more artificial sound being a bit grainy or sounding like cellophane on a fruit basket being crinkled. Although a bit more present than ought be, cymbals sound clearly more natural on the M4U 8. This may be a result of the analog noise canceling circuit of the M4U 8.

The Experience
Basically, the "RoomFeel" response of these headphones has about the right shape, but is a bit over-emphatic in the bass and presence region. It's like having slightly magnified hearing...which brought about an unusual experience for me as I did my listening tests.

With music I found the sharpness at 3kHz a little problematic. My brain didn't accomodate this character very well and it was something I continued to hear. In comparing them to the Bose QC35, I felt the tonality better on the Bose but its somewhat artificial sound was also a character that persisted. I would characterise both these problems as modest, and certainly quite minor compared to many noise cancelers out there—certainly much less bothersome than the issues I found with the Sennheiser noise cancelers.

With movies it was another story altogether. The slightly exaggerated but properly shaped response curve of the PSMB M4U 8 was, for lack of a better way of putting it, rather like bionic hearing. Even at low listening levels, which I generally prefer when possible, the M4U 8 was able to enunciate voices clearly. I felt absolutely no strain in being able to understand speech; it was a non-issue, I didn't even have to think about it. With the Bose at the same modest levels, voices were not as inteligible; the artificial graininess got in the way. Also, the bigger bass boost of the M4U 8 continued to deliver heft to voices at low volumes that helped to get a more natural sense of the pace and tone of delivery. Bottom line: the PSB was a significantly beter headphone for movie watching; speech intelligibility was fantastic.

It was a bit of a revelation, frankly. I had never heard so clear an example of how a particular tuning worked better for movies than music. To be truthful I had previously assumed that a solid neutral tuning would work best for both, but I no longer believe that to be the case. One would assume movie studios have a very good grip on tonality of sound tracks (better than music possibly due to Dolby and DTS standards) but there are a couple things that may make a diference.

For starters, movies are usually mixed with a center channel. Dialog is almost always primarily sent to the center channel and therefore it has some physical separation from other sounds in the mix that may allow you to concentrate on the speech even though surrounding audio has strong levels. With headphones you don't get a center channel so voices have to compete directly with the audio on the side channels.

The other thing is when listening on the go there is often a significant amount of outside noise. Even with noise canceling, quite a bit of high frequency external noise can be heard. This can add some confusion to the ability to understand speech, especially when playing the movie at modest listening levels. The M4U 8 Seems to be able to easily cut through the clutter.

Summary
The PSB M4U 8 is a solid offering at this price. While styling is a bit clumsy, build quality, materials, control functionality, and accessories are top notch. Fit is a bit cozy, but well suited to portable use for sound isolation and security of fit during activity.

The M4U 8 sound quality in passive mode is good, but a bit bloated with the bass accentuation bleeding into the mids. In active modes I would characterize sound quality as fundamentally neutral with an emphasized bass and a modestly emphasized presence region. While this leads to a slightly too sharp a response in music listening, it provides outstanding speech intelligibility in movie watching and telephone conversation.

I think my overall preference for music listening remains with the Bose QC35, but it's close...damned close. I prefer music on the Bose by a modest amount, but I prefer movie watching on the PSB M4U 8 by a pretty healthy margin. I think these headphones are very well suited to folks who watch a lot of video and movies on their portable devices, and I think they may be particularly well suited for older folks who are starting to get some hearing loss for both movies and music. It's going to edge its way onto the Wall of Fame as a close second to the Bose, with a third no where in sight.

Frankly, I've got my fingers crossed for the upcoming NAD VISO HP70—another very similar Paul Barton design. We'll see.

Video
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