Beautifully designed, the beyerdynamic RSX 660 wireless headphone system includes very comfortable, well-padded closed cups and a highly adjustable padded bridge; readily accessible tuning and volume controls; and a slick look that matches the best wired headphones. They're rather large for wireless headphones, but not overly heavy (about 290g sans batteries), and the extra size gives them enough room to fit over your ears rather than crush them.

The audio quality of the analog 660 RSX, when tuned, was excellent, if a little flat. There was no noticeable line noise or interference, but the volume level was quite limited, as was the bass. Still, for some light listening, the RSX 660 was very good--when we could get it to tune properly, that is.

The RSX 660, operating in the 863MHz band, had serious issues holding a signal in our testing, especially if we were moving around. Often it would drop to a mono signal, or lose the signal altogether for a few seconds. Heavy white noise came into play as we moved up to 12m from the base station (even though it's claimed that the headphones work at 50m or more). We tried both the available channels and extensive tuning at short and long range to get it to work. When it did work, it worked very well, but when we moved position we often had to try to re-tune. With the beyerdynamic, we basically had to find a spot in the house that worked, and stay there.

The base station for the RSX 660 is a little larger than most wireless headphone stations, with good reason--it includes a charging rack for the headphones. It's a nifty touch, although it's a little annoying that you have to reset your fitting adjustments every time you want to plug it into the recharger. According to beyerdynamic, the headphones will last up to 8 hours on a pair of AAA batteries.

If it weren't for the tuning issues, we'd have no problem recommending the RSX 660 headphones. If you plan a relatively static use for the headphones, they might work very well for you--but make sure the people you buy them from offer a money-back guarantee.