How do you describe the phenomenon of a voice that gets louder, starts vibrating more, and becomes unclear at high volumes?
Do you say something like 'it started trembling' or 'it began to crack'?
English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. It only takes a minute to sign up.Sign up to join this community
For the voice, perhaps distorted
to change the natural, normal, or original shape, appearance, or sound of (something) in a way that is usually not attractive or pleasing [Merriam-Webster]
Do you possibly mean "feedback"? That's when the microphone (or the speaker) is turned up too high, and you get a loud ringing sound because one the microphone picks up the speaker audio.
An example would be:"The speaker was turned up so loud that all we could hear was feedback."
Alternative, a loudspeaker that's permanently broken is called "blown-out", as in "The speaker was blown out, so we couldn't understand anything."
The OP's question has me thinking of Hitler's oratorical style which can best be witnessed by looking at old clips of Hitler's Nuremberg addresses to the Nazi-party faithful in the mid to late 1930's, before the outbreak of war in September of '39. To my ear, these accord with the progression of the voice as stated by the OP and for which I would use the word frenzy or frenzied.
"A state or period of uncontrolled or wild excitement" - Frenzy Oxford Dictionary. I think that this could be applied to manner in which Hitler spoke and of his voice
"The speakers are making a buzzing noise"
Buzz — Dictionary
noun 1. a low, vibrating, humming sound, as of bees, machinery, or people talking.