Sennheiser CX 400 sound-isolating earphones review

It's true that you can spend hundreds of pounds on earphones -- such as Shure's SE530s -- but whether or not it's worth doing depends on your needs.

If you're looking for a decent upgrade without spending piles of cash, you could get away with spending £30-50 on a pair that may suit you down to the proverbial ground. Sennheiser's sound-isolating CX 400 earphones are in such a bracket. At £39 they're by no means extortionately priced, but is it worth paying even a little more? We decided to find out.

Strengths
For less than the price of a single top title videogame, you're getting a complete package with the CX 400s. In the box is a range of differently-sized silicon tips (these are the passive sound-isolators), gold-plated connectors on both the 1m extension cable and the earphones themselves, a snazzy cable clip and a good-looking carry pouch. Few earphones in this price range come with this sort of accessory bundle.

But it's not just high-quality extras we're impressed with -- the lightweight and attractive earphone enclosures are comfortable and unintrusive, and of course the range of silicon tips provided let you pick the size most comfortable for you. This is important as well for bass performance, since the cosiest fit will enhance that deep bass and those pounding kick drums. Isolation will make a massive difference on the commute, too, with rumbles, whispers and sneezes deadened to almost inaudibility.

Aesthetics aside, the technicalities are equally impressive. The low-end response frequency of 17Hz is low enough to give the aforementioned bass and drums even lower resonance -- a big plus if you're into the electronic and dance scenes. The gold-plated connections are condusive to superb sound quality and are, again, something not frequently seen on earphones at this price.

This decent low-end performance rightly suggested that overall sound quality was good, considering price. The CX 400s offer a clean, clear and detailed sound, with decent mids and excellent overall tone, and instruments that aren't overly boxed in for £39 earphones. Some overly-produced alternative rock from Story Of The Year had pounding bass resounding underneath a compressed snare that tore past our eardrums, with cymbals sparkling brightly in the high-end.

Weaknesses
There was mild unbalance from the bass, the Achilles' heel of these 'phones. Although generally balanced in sound, they're noticeably bass-prominent at the mild expense of the high-end during bassier tracks.

Ingrid Michaelson's stunning album-opener 'Die Alone' didn't quite earn the same studio representation as she did with Senn's CX 500s, although she blew us off our feet when compared to Apple's stock earbuds. So what does that mean?

Conclusion
Well, it means as upgrades from any MP3 player's bundled earphones, the CX 400s stand as being the best value you'll find, with extremely good performance in spite of their affordability. Along with great sound quality for the money, they come with terrific accessories and sport attention to detail rarely seen in this price range. If you want to see what even a small investment in earphones will give you, you won't go far wrong with these gems.

But if you're prepared to spend just a little extra moolah, check Sennheiser's CX 500s. These are the top model in the series and will give you noticeably greater performance for little over a tenner more than the 400s. You'll get a bonus in-line remote, but lose the detachable extension cable.

Edited by Jason Jenkins
Additional editing by Shannon Doubleday