Stop it PH!
This noise thing....I think it's not so much to do with whether the cylinders are inline or not, it's to do with the relative spacing of the crank pins. That's what basically derives the firing sequence and the noise.
You can stick the cylinders anywhere to suit the package and I seem to remember an old Lancia engine that was actually a V4 but ran and sounded like an IL4 because owners didn't want them to sound too agricultural! And you get it on aeroplanes too - the difference between say a Spitfire (Merlin V12) and a Sea Fury (Centaurus 18 radial).
And I'm sure fizzwheel is right re balancers: you get huge harmonics because the firing impulses are not balanced. I read somewhere that the early big-bangers just shook themselves to bits!
I'm off now...I've bored even myself!