Noble Audio Even in the big-budget world of audiophiles, it's rare for a pair of headphones to run more than $500. The FoKus Apollo headset already commanded a pro-tier price when it debuted, but now Noble Audio is releasing an actual pro version of the headset. By and large, the specs between versions are pretty similar, which makes the small price bump between models a little less surprising. The original set retailed for $649 at launch, and the FoKus Apollo Pro will debut at $699. The headset will go on sale globally later this week. Our review of the original FoKus Apollo headphones found that the company's goal of attaining the best possible sound quality was largely accomplished thanks to its unusual approach to drivers. The FoKus Apollo Pro leverages the same hybrid driver tech, combining a dynamic driver for powerful bass and a planar magnetic driver to provide clarity and detail.…