First off I don't think they belong in the post-metal genre; I'm mainly talking about the experimental side of it, so we can throw that out of the window.
With that in mind, if we look at what would qualify as "experimental metal" as a definition, then to me Mudvayne certainly seems to fall in quite nicely. I hate to use Wikipedia but the first few sentences explains it very well in my opinion.
"[Experimental metal/avant-garde metal is] loosely defined by use of experimentation and innovative, avant-garde elements, including non-standard and unconventional sounds, instruments, song structures, playing styles, and vocal techniques."
I would tend to agree that this is what it means and PA seems to as well, seeing as it's own definition practically states the same thing:
"Experimental progressive metal is a sub-genre of progressive metal characterized by the incorporation of innovative, eclectic elements, large-scale experimentation and the use of non-standard and unconventional sounds, instruments, song structures, playing styles, and vocal techniques."
I simply believe that the band does fall into these categories, especially with material from their first two albums, but I digress.
Edited by aglasshouse - July 28 2016 at 10:21