Ahhhhhh, very intriguing! There's a very interesting correlation between artistic people, gearhead pursuits, and music. You're one of the most artistic people here, a total gearhead, and you like the sound of the triple. How cool is that?!
The bike's sound is based mathematically on the resonances produced by the engine, its intake and its exhaust ... in fact its harmonics are very similar to those of a bassoon. A twin has its own signature sound, and an inline four-cylinder engine has its own tonal characteristics. Each require different tunings to run right, and can be compared to different musical instruments.
Aesthetics come from the visual, mechanical and tonal. Very very cool.