Each speaker houses two drivers in the front, as well as a bass port exiting out the top, and as you'd expect the upper and lower frequencies are split between the two. However, and this is where the large part of the high cost comes in, the HD50s don't just use a passive crossover to control how the audio signal is split, they actually use two separate amps for each type of driver.
The reasons for doing this should be obvious but for those of you not familiar with audiophile technobabble I'll explain a bit further. Basically, dedicating an amp to a single type of driver enables it to be optimized to get the best out of it without compromising fidelity on other drivers. So, for instance, if a song has a strong, punchy bassline, the low frequency amp can busy itself providing enough power to keep things pumping, leaving the upper frequency amp to pick out the details undisturbed. The result is a much tighter sound that shouldn't become strained and muffled no matter how much you crank the volume.
Accompanying these improvements in circuitry, the cones used in each driver are also made from super lightweight and rigid titanium, so the audio signal is given the best chance of transitioning from electron to airwave, noise free.
Of course, all these behind the scenes improvements would be moot were the HD50s not to sound good. So, it's a relief to be able to report that that indeed they do. In fact, at times they can sound quite incredible. Unfortunately, at other times, they simply don't cut the mustard.
In terms of sheer clarity they are probably without equal for such small self contained units. Classical, acoustic, and jazz, sounds simply sublime with the most open, airy, balanced and convincing soundscape I've heard from a set of computer speakers. The effect is particularly pronounced because larger speakers lend themselves to being heard from a distance - sit back a couple of metres from the T20s or the T40s and they sound superb but up close they can sound flat. A quick session of Miles Davis from his classic Kind of Blue album perfectly highlights these differences with the piano, trumpet, double bass, and drums all sounding distinct and perfectly placed. So good are the HD50s, I may even learn to like Jazz at this rate.