sonic vision for the blind

The vOICe system allows blind people to get a representation of the visual world through sound. But our brains already have a way of mapping sound to space, and it works pretty well. So why not make use of the already existing system? I'm picturing some kind of pleasant sound tracing around the outlines of objects and walls, playing as if the sound were actually coming from the true point in space. Or a path might be marked out by a series of different virtual windchimes, so that the safe path to walk can be heard as increasingly faint sounds. One couldn't make everything in the environment emit noise-- it would be a cacaphony-- but you could easily have dozens of noise sources placed around in space if they were different enough from each other. The particular sound made could be tied to the meaning of the object.
Do you see how this would make so much more sense than mapping pitch to height and volume to brightness? The sonar clicking method also requires a lot of training. The method I'm suggesting is something we all already know how to do, the brain wouldn't need to be remapped at all. Plus, the sounds wouldn't be so awful as pure tones, they could be as pleasant as we could invent.