We've tried few headphones that match the fidelity of the Denon AH-C551s.
The Denon AH-C551s provide impressive acoustic detail across the range, a rich smooth sound in the bass, high and mids, with astonishing audio clarity for a set that costs just £70.
The Denon AH-C551s are in-ear headphones that are built to last from machined aluminium, with soft plastic earpieces (they ship with small, medium, and large earpieces and we found them easy to swap).
While in-ear sets aren't to everybody's tastes - some people don't like the sensation of sticking something inside their ear canal - we found the Denon AH-C551s comfortable to wear and appreciated the good job they do of filtering out external sound, so you can turn the volume down and still hear the music.
While some headphones ship with flimsy rubber-coated cables that get twisted easily, others deploy cables which are so firm they have the habit of wrenching the earpieces out. Denon's avoided both mistakes, so the Denon AH-C551's cables won't get in the way.
We can't get over the audio quality. After all, that's what you buy headphones for, isn't it? And in the Denon AH-C551 set Denon has clearly applied the lessons the company, which lays claim to inventing the first consumer CD player, has learned across its 50-year audio history.
The high-quality playback is all the more remarkable when you consider each Denon AH-C551 earpiece hosts just one audio driver. That single 11mm diaphragm drive unit uses Neodymium magnets (pretty much an industry standard now when attempting audio excellence) and deploys the company's ‘Acoustic Optimiser' technology, which balances the sound pressure before and behind the diaphragm to improve music playback.
The Denon AH-C551s frequency range is 15Hz to 24kHz, in essence all the frequencies the human ear can hear (generally accepted to include frequencies between 15Hz-20kHz). For comparison's sake, the critically-acclaimed Shure SE530's deliver a range between 18Hz-19kHz. It's academic, both sets sound good, really good, the difference is the latter set cost around £250 more.
The Denon AH-C551s ship with a small rigid case, carry a gold-plated mini-jack connector.