i know that the creator uses audacity so that is why im asking 
a steep low-pass filter at 4000Hz, (or lower), on the vocal.
There’s also a resonance, (comb filter ?),
maybe data compression artifacts, (like it’s been recorded over the phone).
hmmm doesnt sound quite right. also i meant replicate* : p
https://www.youtube.com/watch?v=QSsdLTnSctA heres another example