Low pitch IS a "regular horn" as far as it's design and tuning. There were some "high pitch" horns made up until about the 1930's-ish. "Low pitch" (often identified with the words themselves or a shortened "LP" or "L" near the serial number) is to identify horns made in that timeframe as those horns designed to tune to A=440. Back then, some European tuning conventions used a slightly higher pitch for A - hence "high-pitch", but I'm pretty sure we're all back to A=440 for general purposes. It is possible that a high-pitched horn could be made to play in tune with careful mouthpiece selection, but I would consider it generally not worth the hassle to do so. Stick with low-pitch horns unless you are an obsessive collector and find some intrinsic value in owning one.