The KLH Ultimate One is an extremely comfortable headphone. Together, the combination of light weight, wide range of band adjustability, adequate (but not excessive) side-pressure, padded headband and large over-ear ear pads, make it easy to forget you are wearing headphones, especially during extended listening sessions. My only ergonomic quibble is with the termination where the cable connects with the headphone. The 1.9cm long stiff barrel on the end of the termination could, if torqued sideways, damage the headphone’s input connector (a soft, flexible barrel could eliminate this potential problem).
Sonically, the KLH Ultimate One delivers a classic large-diaphragm dynamic driver sound. The soundstage (with the right music) is large, cohesive, and dimensional. Listening to my recent live recording of the local neo-old-timey band, Masontown, I noticed that the KLH Ultimate One reproduced all the subtleties of the recording. Compared with several of my reference headphones the KLH harmonic balance was quite close, with the exception being the bass, which was fuller and slightly less controlled than through the Focal Elegia or Abyss Diana Phi. Lateral focus and image definition was good through the KLH Ultimate Ones, but again the two reference headphones delivered a somewhat more precise and better-defined three-dimensional image.
One especially attractive aspect of the KLH Ultimate One’s sound was an extremely natural and relaxed sonic presentation that always sounds musical. Unlike many “mid-priced” headphones that aim for a spectacular sound that emphasizes certain parts of the harmonic spectrum, such as the mid bass or the upper midrange. The KLH Ultimate One’s would be an excellent choice for someone who wants a musical over-ear headphone that allows for a high level of situational awareness.
I mention ‘situational awareness’ because the KLH Ultimate Ones do not isolate you from outside noise like a noise cancelling or noise blocking earphone. If your airline decides to change gates, you will still know about it. On the airplane itself you will find the KLH Ultimate Ones do little to reduce noise, so you may need a second pair of earphones that can isolate you from jet engine sounds.
Listeners looking for exceedingly comfortable, open-back, over-ear headphones that deliver a relaxed and musical presentation would do well to try the KLH Ultimate Ones. After a couple of minutes, you may find them hard to take off…
Type: Over-ear, open-back headphones
Driver complement: 50mm dynamic drivers with Beryllium diaphragms
Frequency Response: 18 Hz–22 KHz (± 3 dB)
Impedance: 32 ohms
Sensitivity: 97 dB/1mw
Connector: 3.5mm single-pin custom
Weight: 340 g
Price: £299 UK, $299 US
Manufactured by: KLH
984 Logan Street, Noblesville, Indiana 46060 USA
Tel: +1 (833) 554-8326
Distributed in the UK by: KLH (EU)
Unit 5 Keypoint, Rosemount Business Park
Dublin 11 D11 PT97 Ireland