The AKG Q350 earphones use dynamic drivers, one in each bud responsible for the full spread of frequencies from the claimed 12 - 23,500 Hz range. They exhibit a sound typical of this type of driver - there's plenty of bass on show.
Although a little overblown, the large low-end doesn't leave these earphones sounding a muddy mess, as you'll find with some other bass-heavy dynamic sets. However, strange things are going on up top here. The treble here is not natural, sounding oddly affected, as if it has been passed through some sort of bizarre boxy EQ preset.
The effect of this flawed treble is most noticeable upon first audition, and its effects diminish somewhat as your brain gets used to the coloured Q350 tone, but never leaves entirely. It leaves voices that rely on treble resolution for a decent representation, like Regina Spektor's, sounding clipped and compromised.
It's not all bad though. The exuberant bass and wide sound stage - presumably aided by the semi-open design afforded by those side ports on each earbud - make the AKG Q350 sound fun and bouncy once you've acclimatised to their quirks.
At around £60, the AKG Q 350 are planted in territory where earphones start to sound seriously good. And to be honest, the AKG Q 350 don't - not compared to some 'phones available at a similar price. They manage to avoid the worst sonic sins of harsh sibilance and show-stopping bass bloat, but we find it hard to find a reason to recommend them over alternatives from Sennheiser, Ultimate Ears, et al. Unless you really love lime green.
The AKG Q 350 are fun earphones, with a big, bouncy bass and a surprisingly expansive sound, but are scuppered by an unnatural treble and a design that makes them feel cheaper than they are. They take some getting used to, and do provide some sonic satisfaction once you've gotten over this hump. Better earphones are out there at for the same money though.