Review: Sennheiser RS130 and RS140 headphones

Sennheiser's latest brace of hi-fi headphones may have the same underlying principle, and very similar styling, but they're aimed at subtly different markets. Both are overhead models with a wide padded headband and large padded over-ear cups which swivel in their cradles. They're both wireless, using radio frequencies on three different levels to transmit the audio signal from the base station, which incidentally plugs into both the mains and the sound source.

Usefully, it's unnecessary to plug the phones into the charging stand - they merely rest on the hook at the top and charge automatically when the metal contacts in each connect. A full 16 hours is recommended for the first charge, after which they only need to be replaced for the amount of time you've used them to bring the rechargeable AAA batteries in the headphones back up to full power, with a full charge lasting for up to 22 hours. Both models can be used up to 150m (500 feet) from the transmitter/charging station.

Set up could hardly be simpler in both cases. Just plug 'em in, charge 'em up and they'll automatically tune to the relevant frequency and they're ready to go. If you have trouble with radio interference simply switch the channel on the charging station to one of the three available, find the same on the headphones and you're back in business.

So far, so similar, but that's pretty much where the similarities end. Y'see, each model is designed with completely different users in mind. The RS130 is an open backed model intended primarily for audio and DJ listening.

What's the point of open back headphones? Simply put, they can sound better, though your immediate neighbours won't necessarily thank you for it. In the past, all headphones were essentially closed, until it was discovered that it was possible to get a better sound by allowing both sides of the headphone speaker diaphragm access to the open air. So it is that the RS130 and others like it have an opening on the outer side, which means that the diaphragm can push and pull equally as it vibrates, rather than encountering a fixed mass of air that acts like a spring, restricting its movement.

That's the theory anyway, more of how it sounds in practice later, but it's a fact that open back headphones always sound louder to people nearby than the closed back variety. And that's not to say that closed back headphones are completely silent - even with the best there will be some leakage.

Performance
For fit and comfort there's little to choose between these two devices - a preference for velvet (RS130) over soft leatherette (RS140) may influence your decision here, but both are equally comfortable over fairly long periods.

Listening to music on both, the RS130 offers an arguably warmer sound, though far from fuzzy, while the RS140 succeeds in deriving a smidgeon more detail, particularly in quieter pieces such as Craig Armstrong's solo Piano Works.

Each headphone comes with its own sound enhancement technology. The RS130 has a Surround switch on the charger, which serves several purposes. It increases the perceived volume slightly, but also effectively widens the soundstage, as you might expect, while adding a touch of richness to the sound. It's easy to see why some might prefer it, but there's also the suspicion that it sounds a little forced, and not quite what the music makers intended. Still, after a few minutes listening you quickly adjust to the extended sound stage and more rounded harmonics - it may not be precise, but it's certainly comfortable.

Used with surround sound movies, it offers an impressively wide soundstage which, while not a substitute for the real thing, at least allows you to enjoy a semblance of surround sound on the QT.

The closed back RS140 meanwhile adds the ability to adjust the volume balance between each ear - useful for DJs who prefer to use just one ear cup or if your hearing ability varies between each ear (the overall volume can also be cranked up slightly higher than its sister device). There's also the option to use dynamic compression, operated by a switch on the charger. This makes the dynamic range of the music narrower, raising the level of quieter passages and decreasing the level of louder passages so that the music all sounds at more or less the same level.

Again, this certainly isn't what the music makers would have intended, but on a practical level, in a noisy club environment, it makes it easier to make out the music at lower levels. Used with home cinema, it can also help make speech more intelligible, and reduce the scale of explosions to more manageable levels.