for shit sakes moderators   You keep deleting my contribution even though its true and no im not making it up how do i know this my best friend helps to set up concert venues and has been doing that for  years now  when a microphone is inclosed in a concave divice or even when a hand is holding the part you speak in it creates a loop for the sound thus causing minor feedback sometimes it comes in the form of echoing distortions and other times it comes in the form of howling and screaching so moderators and those who keep deleting my contributions for shit sakes