Unlikely as it seems, residents of Moldova, a small and impoverished country in eastern Europe, recently became the first people in the world to be able to make high-definition mobile phone calls. Orange, the mobile operator launching the service, claims that locals have been astonished by the quality and sensitivity of HD voice calls, which reputedly can pick up whispers and enable crystal clear conversations even in train stations and other noisy environments.

That kind of sound quality clearly requires more bandwidth and Orange is using its Moldovian unit’s brand spanking new HSPA network, which runs at a peak downlink speed of 14.4Mbps and peak uplink speed of 5.76Mbps, to deliver the service. HD voice also requires both people involved in the phone call to be using special and pricey HD handsets, which are currently few and far between. But Orange, which hopes to also launch mobile HD voice in the U.K. and Belgium by the end of 2010, expects the technology to become a mainstream feature in HSPA handsets within five years.

Some service providers, including Orange, already offer high-definition Voice-Over-IP (VOIP) services to fixed-line broadband customers. In fact, Orange claims to have sold more than half a million compatible HD devices since its HD VOIP service was launched in France in 2006.

While it is easy to imagine business users, cutting back on expensive and time-consuming travel, paying a premium for HD voice services in their offices as they look to really engage with clients, it isn’t crystal clear that the service needs to be available on capacity-constrained mobile networks. At the same time, mobile users, who often to have to contend with background noise, might have the most to gain from HD services.

What do you think? Are HD voice services a good use of the capacity created by HSPA?