What is it that makes a Cummins sound like a Cummins?

[DZink24]

This question may not have an answer, and it may be a stupid question. I may be crazy, but am I the only one that just "knows" that a big rig, dump truck or 18 wheeler has the big C under the hood, just by the sound? Obviously, our trucks sound the same as many Fed Ex and UPS trucks, because well, they are running the 5.9 as well. But for example, what is it that makes my straight piped truck sound almost identical to, lets say a Pete with a straight piped M-11 under the hood? It is just uncanny how it seems that all Cummins sound very similar to each other, and can definitely stand out against Cats, Detroits, Internationals, Isuzu, ect.

Is it similiar parts used across the Cummins line, like injectors, turbos, manifolds, and injection pumps?

My response to friends that say "God, your truck sounds like a Mack dump truck!" is , "um no, actually, it sounds like a KW pulling a 15 ton dozer up a grade. Jealous?"

*OR* am I nuts and Cummins are in a pretty even mix of big trucks, and not mostly in Petes and KW? Don't be shy