[dasKrokodil]

But regardless of how much you practice, not all key combinations can physically be performed at the same speed, because some keys are easier to reach than others. So again, either you adjust all your typing to a constant rhythm and waste speed potential on the faster combinations, or you just accept variable speeds.

The comparison with musical instruments doesn't make that much sense because in music, the constant rhythm is required to stay in time. This requirement doesn't exist in typing.