How many people out there like headphone cords? Probably not a great number, but audiophiles will tell you that hard-wired headphones offer far superior sound quality than their wireless counterparts. Sennheiser, however, would have us believe otherwise. The company states that thanks to its Direct Sequence Spread Spectrum (DSSS) technique, its new RS 220 wireless headphones sound like they've got a cord coming out of 'em.
DSSS, as described by Sennheiser, "is a frequency spreading process in which the output signal is spread to a width of 22 MHz by means of a specified bit sequence." This means that the audio data is transmitted simultaneously on several different frequencies, so if one frequency experiences interference, the data is still able to get through on one or more others.
The RS 220 system also doesn't assign an optimum signal volume to its digital data packages. This is a good thing, as it keeps the dynamic range of the music intact - some wireless systems average out the signal, so the quiet sections of a piece end up being louder than intended, and the loud parts quieter.
The headphones themselves incorporate dynamic transducers with neodymium magnets, have a frequency response of 19 to 21,000 hertz, and a maximum sound pressure level of 106 decibels. They are powered by a rechargeable battery pack, which offers eight hours of music playback per charge. Onboard controls allow users to adjust volume and balance, select tracks, and to switch between audio sources, as the transmitter has analogue, coaxial digital and optical digital inputs.
The transmitter puts out an uncompressed 2.4 GHz signal, which can reach the headphones' receiver at a distance of up to 100 meters (328 ft) within a clean line of sight, or 30 meters (98 ft) if not in the same room. It can also serve two sets of the headphones at once.
Sennheiser's RS 220 wireless headphones are due to arrive in stores this month, at an as-yet unknown price.