Why does moving a peak filter (or two at the same time) create a vowel effect?

When making a growl noise, why does that create the opening up of a vowel sound?

Submitted May 20, 2017 at 08:34AM by AtlasAtlasAtlas https://www.reddit.com/r/edmproduction/comments/6c9wu4/why_does_moving_a_peak_filter_or_two_at_the_same/?utm_source=ifttt