Bookcase diffuser/detractor?

Was thinking of putting 3 bookshelves with my records, CDs, movies, books, etc., in them on my backwall and use it for diffusion/diffraction.. anyone have anything similar, experience, or info if this would work? Is it better than just a bare wall? Read mixed reviews.
Yes, it is better than just a bare flat wall. No, it is not as good as an equally large and well-designed diffuser. Very few of which are any good at storing movies, books, etc. My room has four large book cases in back. When you do something like this its amazingly simple to test and see how well it works. Clap your hands. Listen. Works. Infinitely better than asking a bunch of random dudes. You got lucky this time.
Anything uneven and with varying reflectivity is much better than bare walls. Add some tchotchkes, too. Everything helps.
Where do I clap from? Anywhere and just listen to reflections? If I hear them, then what? I was going to put all my records in the bookcases bc theyre overflowing, which would make it uniform... but your saying to mix and match media for better for diffraction/diffustion? Should I put other objects like pictures, etc in the bookcase?
I vary the spine depth on all the books on my shelves to provide some additional scattering.