PXC 150 Noise Guard
Sennheiser’s PXC 150 over-the-ear headphones claim to kill up to 70 per cent of background noise, so you can minimise disturbance but should still hear any warning sounds around you.
The black headphones consist of soft cushioned earpieces that mount across the top of your head with a lightweight metal ear-to-ear harness. They are comfortable to wear, even for long periods. You can fold them up when not in use and pop them into the protective travel pouch they ship with.
The accompanying power supply also integrates the technology Sennheiser uses to cancel sound. The power supply links to your iPod using a permanently tethered line-in jack. There’s 1.8m of cabling that ties all the components together – you can’t detach the power adaptor from the headphones, for those times when you just want to listen to music-cancelling noise.
The adaptor looks like a fat marker pen, and hosts a carrying clip as well as an on/off button to activate noise cancelling. It’s powered by a pair of AAA batteries. It’s a shame it’s so bulky – 13.5cms long and about 2.3cms thick on its thickest side, which may be a turn-off to music lovers who don’t want too much stuff weighing down their pockets. A red LED light on the supply illuminates when it is switched on. You get a lot of use out of one set of batteries, the company claims up to 80-hours on a fresh set. You can also hear music with the headphones switched-off, though it’s a little muted.
Despite the bulk, these are effective at what they do. When used on a long train journey, the PXC 150’s managed to block out all the background noise, including loud conversations and in-train announcements urging passengers to visit the buffet car. At the same time, the ticket collector was audible, and that’s a good thing, as it means wearing these headphones won’t leave you utterly alienated from your surroundings. (The system ships with two adaptors for entertainment systems, including a 6.3mm stereo jack and a 3.5mm double mono jack.)
The technology used in the PXC 150’s is called Noise Guard, an active noise-cancelling technology. This monitors ambient sound before it reaches your ears using tiny microphones. As sound is detected, the system quickly inverts it and despatches another sound through the headphones that’s designed to cancel those ambient noises out. This is called phase cancellation, which means that while noise is taking place, you aren’t aware of it.
Apart from protecting you from background noise, these types of headphones also help you keep your hearing. Keeping noise levels low means you don’t need to raise the iPod’s volume to its maximum in order to enjoy your music, even in noisy places.
The only problem with these headphones is that someone sitting near you may be able to hear some noise leaking from them because over-the-ear headphones do have some sound leak.
While not pretending to offer the world’s best sound output, the PXC 150s don’t disappoint. The headphones offer a good sound stage. Bass is good, but doesn’t dominate – if you like bass-heavy music you may find it lacks a little punch. Delicate acoustic mid-range moments still resonate. Put together, bass, mid-range and treble all work together to deliver a lifelike sound that’s full of nuances. At times, the reproduction exposes the slight loss of quality you get from using digitally compressed files, but that’s the fault of the bit rate at which you digitise your audio.
These noise-cancelling headphones are also helpful if you don’t want to listen to music, as you can simply wear them with the sound-cancelling device switched on to block out background noise – ideal if you want to catch up on your sleep or focus on work while in transit, though they do seem to create a slight hiss when used in this way – better than the sound you are blocking out, but perhaps not ideal.
These headphones are relatively affordable, comfortable to wear and offer good sound reproduction. If you’re looking for a pair of over-the-ear noise-cancelling headphones at this kind of price then these are a safe bet. However, the battery pack is bulky and does detract from an overall well-designed product. One other nice thing? Sennheiser offers a two-year guarantee.