But the Keeper's voice in those two "Cage"-only scenes (Malachi Throne) was digitally monkeyed with (amazing what we can do nowadays) to make it sound higher pitched--like Vic Perrin's overdubs in the rest of the Menagerie.
No. No. It is not Vic Perrin. It doesn't sound a thing like Vic Perrin, and I have no idea how that myth got started. As stated above, it is Malachi Throne's own voice, his original voiceover recording for "The Cage," electronically reprocessed with a higher pitch. It's not just "nowadays" that we can do that. They had the same capability in 1964, although it was done by analog rather than digital means. (And it's not speeding up either; I recently saw a 1974-ish Mission: Impossible
episode where Nimoy played a dual role, and his near-lookalike had his voice electronically raised in the same way, but it obviously matched the speed of his on-camera line readings.)
Compare the Keeper's voice to Vic Perrin's and there's no resemblance. Perrin's voice is about an octave lower than the Keeper's and much more resonant, and his cadence and delivery are different too. Compare the Keeper's voice to other cases of male voices electronically raised in pitch, such as most of the Asgard from Stargate SG-1
, and there's clearly a similar timbre. Compare it to the unaltered Malachi Throne voiceovers from the original "Cage" and the Keeper's high-pitched voice has the same cadence and intonation.
For the Remastered edition, the audio of Throne's voice from "The Cage" is raised in pitch to match the audio from "The Menagerie."