Sennheiser is no stranger to making quality wireless audio products, as evidenced by the RS 170 headphones. The PX 210 BT headphones bring that target of great-sounding, wireless audio to a more portable form factor, exchanging Kleer 2.4GHz wireless technology for the more ubiquitous Bluetooth in the process.
Sennheiser's engineers aren't daft, though. They know that the sub-band coding used by standard Bluetooth stereo headsets doesn't provide amazing audio quality. To counter this, the PX 210 BT use the apt-X codec - as also featured by the Creative ZiiSound D5 to great effect. Experience suggests, therefore, that the Bluetooth transceiver won't be a hindrance to these headphones performance. You'd certainly hope not, bearing in mind the £112 asking price.
And actually that's not the only cost to consider. If you want to get the best out of the PX 210 BTs, you'll need a transmitter able to broadcast using apt-X. We were supplied with a Sennheiser BT300i adaptor, which paired automatically, but no doubt third party alternatives will become available in due course. Obviously any device not supporting apt-X can still connect.
The design is cleverly portable, with the earcups twisting 90 degrees inwards, and then folding inside the headband, on hinges. A carrying case is provides in the box, so you don't have to just chuck the PX 210 BTs in a bag unprotected.
There's enough adjustability in the headband that even those with particularly small or large heads shouldn't have any problem getting a good fit. Both the headband and earcups are nicely padded, which helps make the PX 210 BTs comfortable to wear even for long periods. It's possible that the supra-aural design (where the headphones sit on the ear) won't suit some folks, but we had no complaints.
Usefully, and unlike some Bluetooth headsets, the PX 210 BT headphones also feature a headphone jack. Annoyingly this is of the 2.5mm variety, but a 2.5mm to 3.5mm cable is supplied, but it's great to be able to carry on listening to music if the battery conks out half way through a train journey.