These Sennheiser headphones combine high sound quality with comfortable design.
Nearing the top of Sennheiser's range of closed-backed headphones is the HD250, which is priced to compete with the likes of Beyerdynamic's DT150, AKG's K270S and Sony's MDR7506. The design of this headphone has been evolving for a considerable time, and its most recent form is the Linear II. The technical specifications are very good, as you would expect from this company, with a frequency response extending between 10Hz and 25kHz (-3dB points). Sennheiser also quote a range of 5Hz to 45kHz (-10dB limits) as this spec is more directly comparable with the specs often presented by other headphone manufacturers (who often use -10dB limits without specifying them as such).
The 40mm drivers employ triple-wound aluminium voice coils which have a nominal impedance of a fairly high 300Ω and a correspondingly lower nominal sensitivity of 94dB/mW. The earpiece design is circumaural (it sits around the ear rather than on it) and it exerts a comfortable three Newtons of force to the sides of the head. The headphones are also very light at 215g, with a two-part headband which is easy to adjust and stable in use. The earpads can be replaced easily and the handbook quotes the relevant part order number, but there are no details of how to replace other components -- not even the connecting lead, which is designed to be replaced!
The three-metre connecting cable is made of oxygen free copper fitted with a 3.5mm stereo mini-jack plug and supplied with a push-on adaptor to convert it to a standard 6.3mm stereo jack plug. The cable construction is a simple figure-eight design which is sleeved just before reaching the headphones and splits into two separate wires which connect to each earpiece in the manner of a 'Y'. The connections to the earpieces are via special, very stiff, dual-pronged plugs which allow the cable to be replaced relatively easily should it become damaged. The prongs are different sizes to ensure the phasing of each earpiece is maintained correctly when the lead is replaced.
It's a matter of personal choice, but I don't really like long uncoiled cables on headphones, as I find I'm forever tripping over them. However, I know many who dislike coiled cables as they tend to exert a 'pull' on the headphones -- it's up to the user to make up their own mind about which approach suits them best. Similarly, I'm not a fan of the 'Y' configuration, as I find it tends to get caught up more easily than a single-sided connection, but it does avoid the extra cabling and connections from a single-sided cable inlet to the opposite-side earpiece, which can be failure points in some designs. Having said that, the cable connectors used in this (and many other) Sennheiser designs can become troublesome after many years of heavy service.
Listening to the HD250 Linear II is a pleasure and the headphone is very comfortable to wear for extended periods without the ears becoming hot and sticky. The sound is detailed and accurate, and benefits from Sennheiser's use of 'diffuse field loudness' equalisation -- a skewed frequency balance which was developed to make the sound presentation more like that created by loudspeakers within a room. It certainly sounds natural to me and is not at all fatiguing even over long periods. The earpieces also attenuate ambient noise by a useful amount, which can be very helpful.
There is a good degree of bass extension with low bass drums and synth lines being presented clearly, although the energy level seemed slightly weaker than I would have preferred. This is a common criticism of many headphones, though, and the HD250 Linear II compares very favourably with its obvious competitors. Overall, then, this is a very competent, reliable and accurate closed-back headphone which easily justifies its UK price and fares very well when auditioned alongside its similarly priced competition.