What Sennheiser set out to do with the HD800, and have achieved, is to offer a serious alternative to an electrostatic design - which will only work with a special amplifier and will, as a rule, cost markedly more than the HD800 if they are of equal audio quality. There will always be those who prefer the sound of electrostatics, of course, but the HD800 has a lot to offer and brings a new level of performance in a dynamic design.
While all headphones can be made to sound better by using a dedicated headphone amplifier, the HD800 is versatile enough to be used with anything from a simple CD player upwards. Of course you will want to explore better options, and it is now possible to get excellent headphone amps from $299 in the form of the Musical Fidelity V-CANS. HiFi Choice go so far as to say that the HD800 is now the best transducer on the market. Be that as it may, the final test for most people will be (a) does it vastly exceed the sound quality offered by models like the HD650, and (b) how do they compare to electrostatics costing $3000-$5000. This will be reflected in the timbral accuracy of instruments and voices, the creation of the appropriate spacial cues for location of performers, and an utter lack of distortion, overemphasis and confusion of sonic textures. This translates into smooth, uncoloured, convincing audio that keeps you coming back for more. You'll have to come and listen in order to see which type of headphone you prefer, but we think they've done a brilliant job.
As the press release from Sennheiser outlines: "The exceptional sound properties of the HD 800 are supported by selected materials and a top-quality finish. To ensure that the acoustic properties of the headphones are not impaired by any partial vibrations, the transducer is mounted in a specially produced high-precision gauze made of stainless steel. The ear cups are made of high-quality plastic with particularly good attenuation characteristics. What is more, there is no covering at all for the ear cups, as less material means that there is less opportunity for partial vibrations to occur. For the same reason, a special headband was developed for the HD 800. A patented multi-layer design consisting of metal and high-quality plastic attenuates all of the vibrations of the headband, thus effectively eliminating any dips in sound pressure level at low frequencies. The cables have also been developed especially for these headphones. The four-strand high-performance wires made of silver-plated, low-oxygen copper are specially shielded against electromagnetic disturbance. The two high-precision plugs and the (6.3 mm) jack plug are gold plated for optimum contact."