We will review the Sennheiser RS180 and the Amphony Model 2500. Both of these models utilize digital audio transmission. In other words the headphone transmitter will convert the audio signal into digital data which is transmitted to the headphones. The headphones then convert this data back to audio. Using this transmission technology, none of these headphones showed the static or distortion that we have gotten used to from previous wireless headphones. Both of these models claim to transmit true CD quality audio.
At first glance, the Sennheiser headphones are constructed as open headphones, i.e. sound from the headphone transducers will penetrate to the outside while the Amphony headphones are closed. Choosing open or closed headphones is a matter of personal preference. A closed design, such as the Amphony, will reduce the sound level heard by others which is good when listening at loud volume without bothering others. Both models come with comfortable velours ear cushions and fit snugly.
When not in use, the RS180 headphones can be suspended from the transmitter which acts as a support base. The transmitter offer an analog audio input, yet no digital inputs. The Amphony 2500 transmitter offers analog inputs, one coaxial digital and one optical digital input. As such the Model 2500 transmitter can connect to newer plasma TVs, most of which no longer have analog audio outputs. The Model 2500 transmitter will automatically switch to the correct audio input by detecting which audio input has a valid signal.
One of the most important aspect of headphones is the sound quality. The sound of the RS180 is on the light side with good mid range but a little low on the bass. As such the RS180 is most suitable for listening to vocal racks and light music. The bass response of the Model 2500 is more pronounced than the RS180 but still well balanced and not overly aggressive in any way. The wireless transmission itself no longer suffers from the drawbacks of previous generation models and the sound quality of both models rivals the quality of corded headphones. The only limitation is the fact that wireless headphones are powered by batteries and thus will never be able to blast the same volume as corded headphones connected to a good headphone amp. Having said that, both models achieve plenty of volume though, the Model 2500 more so than the RS180.
The RS180 sends it's signal at 2.4 GHz. It supports up to four headphones per transmitter. The Model 2500 operates at 5.8 GHz and supports an unlimited number of headphones. The operating range of the RS180 is specified by Sennheiser at 300 ft. During our indoor testing we were able to get a clean signal up to around 100 ft with both models which should be sufficient for most users. The Model 2500 transmitter can connect to secondary transmitters which are called RangeBoosters that allow expanding the headphone operating range even further.
Battery life is 15 hours per charge for the RS180 and 30 hours for the Model 2500. The cost is around $300 for the RS180 wireless headphones and $200 for the Model 2500.