Well, I understand what mutes are, Larry, and that was my only guess about that section at :51- it just sounds so strange that I thought maybe it was something else. I think it could be the reverb making it sound off, maybe some EQing that's distorting it, or something.
Sorry to get sidetracked away from the music itself. My main point is that this piece deserves one of your more sophisticated renderings, if your new computer is up to speed, which I'm sure it is.
I will give it a close listen and see if I can determine to what you are referring.
Edit: The measures to which you refer are muted brass playing at FF, nothing more...nothing less. Muted brass playing at this dynamic level tend to sound metallic, depending, of course, on what type of mute is being used.