I talk a lot about the dichotomy between the image of himself Brain projects (cold, calculating super-intelligent being bordering on the abstract) and who he actually is (just a guy), and his voice is a big part of that.

His voice is absolutely iconic and distinctive but it's also very much a Just A Guy voice. The exception to this is in the early Animaniacs shorts where he had that creepy monotone. That fits his image. How he sounded by the end of the spinoff absolutely does not.

And reboot Brain sounds even MORE like Just A Guy than ever, except with additional old man traits. He's just some old man. I love that.
I hope this thread makes sense. It feels kind of incoherent but oh well.