That was, however, in a Sennheiser store, with properly-amped, high-quality music, and just plugging it to my phone and playing music from the in-built audio circuit does this pair of headphones no justice at all. I was very pleased to be linked up by SG Story to the Sennheiser Asia folks, who very readily sent a pair my way for review.
The Set Up
If I were to actually buy this for myself, it would be sitting in office, where I have placed my trusty little tube amp and 30-pin iPhone dock, which in turn holds my iPhone 4 and pipes its music out via Line Out to my amp when connected.
Pretty much everything I have. I've been taking a more orchestral slant so I've been listening to alot of operas, musicals, concertos and symphonies. But I've also tried out rock, hard rock, metal, jazz, blues, funk, post-rock, vocals and some pop, wherever my fancy takes me. I try to have my music source in as high a sample rate as possible, so most of them are in 320kbps, but some of my more complex music like concertos and jazz are in lossless WAV, running at 1411kbps.
The defining factor about the HD 598 is that it is open-canned, meaning that air is free to pass through the earcups, allowing for wider sound reproduction as opposed to closed cans, where the air available to transmit sound is limited from what's within the earcup, up to your ear drum. That is, unfortunately, also it's only pain point. Air moves so freely that people around you can pretty much hear whatever you are listening to, and you can still hear everything that goes around you, even a suppressed cough. Some argue that if people can hear what you are listening to, you're listening to it too loud. And with proper amping, the HD 598 can produce all frequencies evenly at low volumes. But for lack of a better phrase, it's quite simply tak shiok when the music isn't completely washing over you. Even feels like a bit of a waste at times, listening to music so softly when you have such powerful hardware. But to each his own. In fact, even with air flowing so freely, your ears start to feel tired, not from the prolonged cupping of the cushions, but if the volume is too loud.
The thing about the HD 598 is that its transducers deliver music so smoothly that it quite often feels flat. That is not to say the music feels lifeless - rather, it's helped me pay more attention to the details of my music, and rewarded that attention by faithfully reproducing every last bit of audio information that the little bits you never knew were there - a cough, a musician shifting in his chair, a slide on the fret, the sigh of a piano's sustain pedal - presents itself to you and delights the heck out of you.
Along with the open-cans, Sennheiser's Eargonomic Acoustic Refinement technology claims to give you the experience of sitting in front of a hi-fi system. Not sure how effective that has been for me. For sure the soundstage can be matched by few within its class, and stereo separation is well-defined, but it can feel very lateral, instead of the more forward placement you would expect from a hi-fi system.
Bass instruments that are often glossed over by lesser audio products - softly rumbling kettle drums, double basses, the lower harmonics of trombones, even some frequencies of bass guitars, are clearly heard with these headphones without getting too overwhelming.
The same can be said for the high frequencies. I have yet to hear something that could push the headphones' high frequency output into "ear-piercing" territory. Cymbal clashes, crashes and bashes, high notes of female singers, piccolos, trumpets and usually painful guitar squeals are all pumped out clearly yet tolerably, allowing you to enjoy musical climaxes without destroying your eardrums.
Mids have an unfortunate chance of getting overshadowed by the higher frequencies, but I've only heard that happen when everything is playing together, for example when chorus and orchestra are both going at full volume. If there is a tenor or baritone singing however, you can be damn sure that they'll cut through and be the centre of your attention. Even if they've been mixed to be in the background.
The recommended price of S$399 is a hefty one to pay if it's your first or second time making the jump to higher quality audio. And it's seldom worth it unless you already have an amping system in place that can provide proper output support. Music forced at loud volume from inferior audio circuits merely sound like wind through a tunnel. Try plugging any high quality headphone to your iPhone and maxing out the volume to see what I mean. Not a pleasant experience, and certainly not an experience worth draining your player's battery for. But if you want to jump into the world of audio goodness, and are willing to pay for an amp, the HD 598 offers amazing value for what you are paying, and should last you a very long time in your journey towards better music.