All of this is with the Reference filter in place. Swapping out for the bass boost (really a mid-treble cut) does give the impression of deeper bass… but it is an impression. Ditto the treble boost, in reverse. I significantly prefer the Reference filter because it made the vocals sound ‘right’, although the boost filters are significantly less heavy-handed than heavy-handed tone-shaping from a portable source. With the treble-boost filter in place, the K3003 still delivered good and neutral bass. I found the treble boost lifted the midrange and treble, but not the high treble. If anything, it seemed to make the treble even more ‘pure’ sounding than the Reference, although the Reference is the better balanced sound overall. Meanwhile, the bass boost makes the K3003 more in line with a lot of popular IEMs and headphones; no, it’s not a Beats-beater and doesn’t turn fey folk into deep dubstep, but it gives the K3003 a brooding, big bass sound.
Comparing the snarling Nick Cave vocals on the first and eponymous Grinderman album [Mute, CD] with Elizabeth Fraser’s vocal on Teardrop from Massive Attack’s Mezzanine [Virgin, CD] is fascinating. Cave’s primal growl is surprisingly articulate, his diction bringing out the vitriol of the lyrics and that is presented perfectly here. Meanwhile, Fraser’s almost fey breathy vocals are harder to resolve under any circumstance (the lyrics are ‘poetic’ to the point of almost being word salad) but the K3003 does better than most. Nevertheless, the IEM does seem to mildly accent the breathy part of her voice… perhaps the nearest this gets to deviating from absolute fidelity.
The bass boost filter brings out some of the dark, brooding power of music, while the treble boost filter helped bring voices up out of the mix. On balance though, I still prefer the Reference.
Expensive? Of course, but the K3003/3003i does make a good argument for being worth every penny. They are phenomenally well made, deliver outstanding sound without being demanding of either source material or player, and bespeak of understated luxury. For the person who understands the best of engineering is reassuringly expensive, this fits the bill perfectly. Unless you are in the habit of carrying round a pair of big Stax headphones with your iPod, this will redefine the sound of your system.
AKG K3003i in-ear monitor/headset
Frequency Response: 10Hz – 30 kHz
Drivers: 40mm Mylar/titanium diaphragm drivers
Sensitivity: 125 dB
Impedance: 8 Ohms
Max. Input Power: 15mW
Cable Length: 1.2m
Weight: 10 grams, without cable
Warranty: Two years, parts and labour
Manufactured by: AKG Acoustics GmbH
Distributed by: Harman Consumer UK