The $99 Sony MDR-RF970RK headphones look like most other over-the-ear headphones, with one subtle difference. These Sonys have no wires and are designed to allow the user complete freedom from the audio source. They also incorporate noise-canceling technology designed to further enhance the quality of your tunes.

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The RF970RK system is comprised of two units: the base and the headphones themselves. The two units are linked by a radio frequency channel, which carries the audio information to the headphones. According to Sony, they will work up to about 150 feet depending on how much clutter is between the base and the headphones. There are three different frequencies that the system can operate on, but it must be selected on the base. It would be nice if you could change frequencies from the headphones.

The base unit also serves as a recharging station for the headphones internal battery. Simply put the headphones back in the cradle and recharging begins via electromagnetic induction. Be warned however that recharging this way is very slow so it's best to keep the headphones in the cradle when not in use. Audio connections are also made in the base and it will accept either RCA or mini-jack cables from your source.

The headphones are closed ear type and are pretty comfortable, except for the annoying spring-loaded head strap. Its purpose is to turn the headphones on only when they are being worn and keep the battery from getting drained, but I'm confident Sony can come up with a more sophisticated way of handling this. The headphone's volume control wheel comes in very handy, especially when being used with a TV cable box as every channel seems to have a different audio level.

So, how does the wireless link work you ask? It's not bad, but it's certainly not perfect either. I primarily use mine in the bedroom to watch TV while my wife sleeps. The transmitter is about twenty feet away and in line-of-sight of the headphones. For this application the 970 works almost perfectly. Start to move around the house however, and you start to hear interference, which usually is a click or hiss. In my home, I would say the interference is minimal as long as I am within a radius of about 90 feet. Go beyond that and the clicks and clacks start to overpower the signal you are trying to listen to. Yes, it will work up to 150 feet as Sony says it will, but it's pretty noisy at that point and more than likely you will take them off or start walking back. The sound quality of the headphones is pretty good, but you will never mistake these for an audiophile headphone. In my opinion these are designed for the convenience first and performance a distant second.

Read Page 2 for The High Points, Low Points and Conclusion

High Points
- The RF970 headphones are extremely convenient and work perfectly if you stay close to the transmitter. Earphones fit snugly over the ear yet are very comfortable for extended listening sessions.

- Wireless headphones offer great freedom and allow you to do lots of chores while keeping up with your favorite TV show or radio station without disturbing everyone in the house.
- Hassle free recharging of the headphones battery is a very nice touch. If you are in a pinch and find yourself with dead batteries you can always use off the shelf AA batteries. Battery life in my experience has never been an issue, but I do keep them in the cradle.

Low Points
- The radio link quality is pretty disappointing. I see no reason why my cordless phone can work perfectly out to my mailbox, but these headphones fall apart simply by moving through a few rooms. Sony should let channel changes be made from the headphones, not at the base.
- Sound quality is only average and anyone looking to use these for high quality music should look elsewhere.

Conclusion
The Sony MDR-RF970RK headphones are great in theory, but fall flat on execution. If you want a pair of headphones that you will use in close proximity of the transmitter, then the Sony might not be a bad choice. They do work pretty well in that capacity, but if you think you will be using the full 150-foot range with outstanding sound quality and no interference then you need to temper your expectations.

Additional Resources
• Read dozens more audiophile headphone reviews from HomeTheaterReview.com.
• Read a review of Bowers and Wilkins P5 Headphones.
• Follow the talk on Audiophile headphones at AudiophileReview.com - a leading high end audiophile blog.