Letting Grado's GR8 'phones down a little is the meagre offering of just three silicone tips: small, medium, and large. When even comparatively cheap earphones are now coming with a plethora of both silicone and foam tips this seems a little bit stingy. The tips are comfortable enough, however, and I was able to get a good seal.
The specs do betray one aspect of the GR8s with alacrity. Their 120ohm impedance means that these 'phones really do benefit from the use of an amplifier. That's not to say that an iPod touch, a Cowon iAudio 9 or a similar player can't drive these earphones well enough for use out and about, but this isn't the ideal setup. Luckily, even something as cheap and cheerful as the FiiO E5 should provide a helpful boost to the output of your PMP of choice.
Thankfully the GR8s compensate for this small inconvenience. If your source does have enough power to drive the GR8s without straining, or you have an amp, the result is commendable. Raise the volume to a decent level and the outcome is a forceful output, but one that doesn't feel at all strained. Cheaper earphones might push out a lot of sound at high volumes, but you can bet that everything will be muddied up like nobody's business. Not so with the Grado GR8s; you're eardrums will give in long before these 'phones.
Another interesting design feature is Grado's use of a single moving armature in the GR8s. Pretty much all earphones at this price range use at least dual-driver if not triple-driver designs - the three year old Ultimate Ears triple.fi 10 Pro Earphones being a prime example of the latter design. A single driver does bring with it the advantage of needing no crossover, which is where most multi-driver earphones fall down. Certainly the GR8s have a beautifully cohesive soundstage. There's no obvious transition between woofers and tweeters to mar the output, just equally clear reproduction of low, mid and high end frequencies.
This cohesiveness doesn't mean there isn't plenty of stereo separation, though. When tracks call for it, the left and right channels maintain a great distinction, which of course helps with developing a wide soundstage and, ultimately, keeps them truer to the recording studio's intentions. Obviously with the drivers sitting in your ear, that special all-encompassing awareness afforded by a great set of headphones isn’t possible, but as IEMs go on this front, the GR8s are up with the best of them.