Sennheiser RS 6-9 Wireless Headphone

• Lightweight wireless headphone with transmitter
• Nickel-metal-hydride "accuplug" battery included
• Volume control on headset
• Three switchable transmission channels for simultaneous operation of multiple headsets
• RF input filter reduces signal interference

The heart of the system is the headphone receiver, a sturdy plastic band lined with an adjustable cushioning band. The 4-inch padded ear cups rest against and not over your ears, joined to the headband in pivot sockets that permit easy angling to fit your head. The other piece central to the RS 6-9 is the FM transmitter, a tiny device you hook up to both an electric outlet and your sound source, then essentially forget about.

The headset runs on a single "accuplug" rechargeable battery, not the sort of thing you pick up at your convenience store. The RS 6-9 comes with one, but be careful: it only runs for three hours at a spell, and if you let it run completely flat you won't be able to recharge it. The battery comes charged and fitted in the headset's right earpiece, just above the conveniently placed volume/on/off switch. Sennheiser strongly recommends 24 hours' charging time before first use, however, so after you've checked to hear that the RS 6-9 works, be sure to put that battery right in the charger! The transmitter offers two charging slots in case you want to stock up.

The transmitter comes with an input cable that plugs into any stereo analog miniplug or 0.25-inch headphone jack, so you can easily feed it audio from your tuner, CD player, DVD player, cassette deck, minidisc, television--you name it, so long as you have a headphone jack on either the source or on your receiver, preamp, or integrated amplifier. We'd prefer a choice between using headphone outputs or RCA jacks, but in an either/or situation, we feel the headphone connection offered here is most conducive to simple setups.

Sennheiser recommends not exceeding 100 meters (about 250 feet) in listening range, and we occasionally experienced interference--similar to FM radio static--at shorter distances, depending on the room. Metal parts, such as those in concrete construction or wall coverings, will reflect radio waves, whereas the audio signal passes unobstructed through wood, plaster, and (apparently) people. Different channels (1-3) permit use of multiple headsets in the same house.

Battery and transmission issues aside, setting up and enjoying the RS 6-9 is really quite simple, requiring little effort to plug in, set the transmission channel, and crank up the tunes. Don't crank the level too high, though--your ears will thank you for it later.

A loudness warning is especially pertinent for this headset since, to our delight, the sound is so good. Rather than attempting to eke the last bit of bass from every sound that rides the airwaves in, this headset presents sound in a way that is nothing if not incredibly musical, letting the music--whether classical, jazz, folk, or punk rock--speak for itself in pure, unfatiguing tones. FM wireless transmission should sound about like good FM radio--it's the same process, after all--but we've never heard FM begin to approach the clarity, dynamic punch, or ease heard from the RS 6-9.

For untethered listening in the garden, around the house, and after others have gone to bed, the RS 6-9 is as trouble-free and capable as many wireless headphones out there. But when it comes to warm and natural sound quality in a wireless setup, this Sennheiser model knows no equal. --Michael Mikesell

Pros:

• Outstanding sonic performance
• Extremely comfortable
• Easy to set up and operate
• Rechargeable battery included
• 0.25-inch adapter included for transmitter hookup

Cons:

• No RCA inputs on transmitter
• Battery dies if exhausted or not recharged
• Does not accept standard batteries