The PXC 450 is the letest from Sennheiser’s travel line of headphones. “Portable” and “circumaueal” generally don’t see eye to eye due to bulk and issues with anchoring them to your head. To remedy this, the PXC 450 has a very firm headband; thankfully, it is padded and well designed enough to not squash your ears.
The patented active noise cancellation technology called NoiseGard 2.0 markes its presence felt. This uses a combination of improved circuitry (over the previous version of NoiseGard), and better microphones (that detect unwanted outside noise). Their noise elimination algorithms have also seen an overhaul. Using NoiseGard will require a single AAA battery. Remove the battry and the PXC450 can function as a regular, wired headphone set.
There’s a talk-through function inbuilt. According to sennheiser, too microphones (one on each cup) pick up external sounds in the immediate vicinity such as someone trying to talk to you. We tested this feature, but it didnot work too well, and and the reviewer had to take off the headphones to hear what the other person was saying. Nevertheless the PXC450 isolates noisc beautifully even with NoiseGard off.
Bass is quite a mixed bag; sometimes its there and goes quite low, on other tracks its not as pronounced as the mids and highs. We’d have liked for these phones to be a little kinder to vocals and mids – which, although forward (not overly so), lack finer detail. (At this point we are comparing them to audiophil grade cans.) Their quick response means the PXC 450 is equally suited for fast heavy metal music as the country or soft rock geners. Thet are rather easy to drive – so using them with your iPod abroad a loisy local or bus is a possibility.
These cans need to be used for around a hundred hours before they actually sound good (burned in, if you will). We found a full 35 to 40 percent difference in quallity and bass reproduction., and the highs are become a little more noticeable. They are still improving after the 120 odd hours that we have spent with them, so, don’t go by the way a brand new pair sounds.
At $750, the PXC 450 is far from affordable. Even if you can foot the bill you will still need to accept that these aren’t the audiophil-grade cans that the price suggests. That said, they’re head and shoulder above most other headphones available in World, and definitely one of the best noise cancelling sets we’ve come across (Including the Bose Companion 5). Of course they are in a price league of their own.

Specification:
8 to 28000 Hz; 150 ohms;
Sound Pressure Level : 108 dB
Cable : 1.4 m
Weight : 240gm
Accessories : Transport Case, 6.3mm stereo adapter.

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