Why does my vinyl sound so bright?

The wall shelf is mounted directly into the studs, however it is an inside wall as an exterior wall was not an option. Regardless, the wall shelf has made a significant difference as the system is on the second floor, previously when walking across the room the TT would bounce, now it is very solid and stable.

I'll look into the mutliple things given here and report back after some experimenting. Thanks everyone, for helping this vinyl imbecile without making me feel like more of one.

Arthur, it's gotta be the move to a wall mount, it doesn't take much to change the character of a TT when changing platforms. I also have the blackbird and it is very revealing.

Okay, this is weird. I adjusted VTA a tad and validated VTF at 2.0 and now music sounds garbled and warbly coming out. I'm guessing the cartridge may have bit the dust or be biting the dust. Maybe the cantilever got damaged somehow when I moved it (although I had the arm secured and it was a pretty short and uneventful trip from rack to wall.)

Any further thoughts?

Yes -- start over and remount the cartridge. Verify ALL parameters, as each will affect the other.

"Garbled and warbly" may mean the cart is disfunctional as you say. Some damage will show up on visual inspection, if you have a clear recollection of how the cart looked when new. Inspect the cantilever to see if it is centred in the mount. Other damage--a failed suspension for example--may be invisible and not show up until you try to play a record.

Is it possible the VTF is reading wrong? That might happen if the counterweight has moved. A setting much too low or much too high might give you garbled and warbly (although warbly might be TT speed instability too, I suppose).

You could start over again, as Ncarv suggests, right back to remounting the cart and balancing the arm. Check to make sure the stylus is clean, first!

It's just a thought, but if you moved the TT to the shelf with the main platter still mounted on the bearing, the suspension could have bounced some. A lot of bounce can throw settings off or worse.