The GR10s certainly have no problem going loud. There's no distortion at any volumes that could be considered safe for the human ear to be prolonged to for any length of time. The result is a reproduction that is forceful, but not forced and there's a particularly good punch to the low-end, which doesn't have the same uncomfortable 'kick-in-the-head' feel of many bass-heavy earphones, and sounds all the better for it.
Unsurprisingly these improvements make the GR10s an exceptional-sounding pair of earphones. Bearing in mind how highly we praised the GR8, it's not a surprise that we're impressed by their successors. That shouldn't detract from the technical achievement of the GR10s, though The GR10s may have a single, moving armature in each earpiece, but they'll happily go toe to toe with triple-driver earphones in the same price range from the likes of Shure and Westone.
It's not just accuracy that the Grado GR10s offer up, though, they also have a huge soundstage for an IEM. That the drivers are sitting in your ear limits the width of this soundstage - music is still definitely coming from within, not without, your ears. The depth that the GR10s produce is nothing short of brilliant, though, and if you're listening to tracks recorded to be played on a real sound system, the benefit is tangible. Live recordings especially benefit from this, with big epic pieces (Space Dementia from Muse's Hullabaloo soundtrack, for example) sounding, well, big and epic.
What really appeals about the GR10s is that, like Grado's high-end headphones, such as the oft-lauded RS-1s (described by many as the best you can buy from any manufacturer), the GR10 earphones are downright fun to listen to. The Grado GR10 earphones they deliver what we can only call a sense of energy, a sense that you want, nay need, to be moving along with whatever music you're listening to. For want of a better description, the GR10s make music sound alive in a way we can't remember any other earphones managing.
We can't ignore the price of the Grado GR10 earphones, they're inescapably expensive, but so are rival earphones such as the Shure SE535s, and we have no qualms about recommending them either - quality never did come cheap. What's more important is whether anyone paying £400 for a pair of Grado GR10s would feel cheated and we simply can't see it happening.