Has anyone looked at the pictures of his room? It looks like a wonderful living space, but nearly the entire front wall is glass, the walls appear to be wood and there's a piano. The above comments about the high number of harmonics, both odd and even, present in organ music are a partial explanation, but I think it's more a room problem that has little to do with digital vs. analog or organ vs. non-organ music. As a test play a close miked solo violin recording. I suspect it too will sound bright and hard.
Why organ music
I have a nice ss - CD set up that satisfies me most of the time, but am re-tasting LP's. The one kind if music that always sounds much better to me on LP, even with my very modest LP system is organ music. I used to play organ myself. But I also play piano and can relish well recorded piano on CD. To me, organ on CD is very hard to listen to. Anyone have idea why I notice such a difference with organ versus other instruments?