Well if we're going to open it up to non-aviation, a auto racing V-12 at speed is music to my ears. First one I heard in person was an IMSA Jaguar big V-12 - first time it went at an IMSA race in Portland, by my buddy and I just looked at each other and smiled.
The Ferrari F-1 engine in the late 1980's to mid 1990s was even better, reving up to over 15,000 rpm - simply beautiful. I actually bought a CD of V-12 engine sounds back in the 1990s
