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Sennheiser PXC 450 headphones review
Quiet and comfortable even at work
I’d actually tried out the Sennheiser PXC 450 NoiseGard™ noise compensation headphones before, as part of our noise-reduction headphone shoot-out. But those evaluations were based on short, structured listening sessions. I was glad to have an opportunity to try them out the way they were meant to be used — in listening sessions stretching over several hours.
Guarding against unwanted noise
Even though I didn’t take these on a plane, I put the PXC 450s to work. There was plenty of ambient noise in our office for the headphones to deal with, and deal with it they did. As with many active-type of noise-cancelation headphones, the PXC 450s did a better job with steady background noises, rather than transient ones.
The reason has to do with the process of noise cancellation. Tiny microphones built into the outside of the earcups pick up the ambient sound surrounding the wearer. That sound is then processed by circuitry, creating a signal that's exactly 180° out of phase with the original noise. That processed signal is then pumped into the earcups. The out-of-phase noise acoustically negates any ambient sound leaking into the earcups, resulting in silence.
Because it takes a fraction of a second for the out-of-phase signal to be generated, it's always slightly behind the source. For ambient sounds that don’t change in volume (or change slowly), that’s not a problem.
So, for example, once I put on the PXC 450s, I ceased hearing the dull, steady hum of our HVAC unit. Without any music playing, silence reigned inside the earcups. When a conversation started in the next cube though, the voices still came through, although significantly muted. I couldn’t quite make out what my colleagues were talking about, but I was aware they were talking.
Press to Talk
In the middle of the right earcup is a Talk button. This feature was designed for airplane travel, but I found it quite useful in the office. It’s a big button with an indented surface that's easy to find just by feel. The button temporarily disables the noise cancelation, and instead sends the signal from the exterior microphones straight through so it's audible.
When someone wished to speak to me, I simply pressed the indented button. My music was muted, and outside sound was relayed through the headphones. I could hear — and respond to — my colleague without having to remove the headphones.
A word about my headphone auditioning setup
I used my standard at-work music setup for these headphones. The headphones were plugged into a NuForce Icon HDP headphone amp/USB DAC/stereo preamp, which is then connected to my laptop via a USB cable. Residing on my laptop are lossless audio files.
The NuForce is the important link the chain, as it serves double duty. First, it’s a headphone amp, which is helpful for auditioning higher-end headphones like the Sennheiser PXC450s. It means they’re not starved for power and can operate at peak efficiency (even at low volume levels). Second, through the USB connection, the NuForce bypasses my laptops marginal digital-to-analog converter (DAC) and uses its own on-board DAC to decode the audio files. And that matters because better conversion ensures higher fidelity.
So even though it’s a simple system, I enjoy better audio than I would get from just plugging the headphones directly into my computer.
Now, about sound quality
Overall, the headphones did a very good job. The sound had a lot of detail in it. The edges sometimes seemed a little soft, but I think that was a side effect of the active noise-cancelation. I especially noticed it in bass-heavy tracks. The low end was present and clear, but on the tracks I was very familiar with it seemed to lack a little bit of impact I normally heard.
That’s not to say that the ‘phones sounded bad — quite the contrary. They did an excellent job with noise canceling (their primary purpose) and delivered better-than-average sound quality. Even though I wasn't sitting on a plane and relying on the PCX 450s to shield me from the drone of the engines, I was more than happy with the sound.
The PXC 450s presented a nice, full soundfield with good stereo imaging.
And let’s not forget comfort
No question — noise-canceling headphones are most useful for travel (especially by air). Which means wearing these headphones for hours on end is the norm rather than the exception. And that’s exactly what I did. I put them on at the start of the workday, and wore them as long as I remained at my desk.
I often wore them for 5-6 hours a day, and they were consistently comfortable the entire time. The earcups fit securely over my ears without applying undue pressure to my temples. The headband padding was more than sufficient to let the phones rest lightly on my head without discomfort.
One thing to be aware of — the drivers are angled in, which means that there are slight bulges inside the earcups. They’re designed to fit in the hollow of the ears, and are small enough to accommodate most ear sizes. I didn't have any trouble with them at all, but there are always exceptions…
The bottom line
The Sennheiser PXC 450 headphone are noise-canceling headphones, and they perform that function admirably. It wasn’t until I put them on that I became aware of just how much office noise I had gotten used to. They also performed well as headphones, delivering my music with a full, detailed sound. And the PXC 450s were so comfortable I sometimes forgot I was wearing headphones – until I realized I could barely hear my coworker. Thank heavens for that talk button!