Thanks for the reply, no it’s all 3 mics - same as the previous stream (Platformer demo), never had a problem with any of the older ones but the last 2!. If you compare the two UE twitch YT vids I linked to in my last post you should be able to hear the dramatic drop in sound quality? no bass, no pressence, tons of distortion when more than one person talks, and god forbid you all laugh at the same time - clipping hell! 
As the old videos still sound fine it can’t be anything my end, I noticed it on the previous stream not just this one and thought you’d purposely changed the setup there and it wasn’t for the better, so can’t understand if you haven’t made any changes. Maybe it’s a TWITCH fault? and you are uploading whatever twitch provides so the problem follows to YouTube too. Has someone changed your audio bandwidth/quality settings for your live streaming? do Twitch themselves limit it based on overusing bandwidth from an account? I have no idea but it’s definitely changed for the worse.
If you can’t hear the difference between the two YT videos (both Epic twitch streams) then perhaps you could try on quality headphones (I use AKG KS240s ), it’s more than apparent. If you on a laptop, tablet, phone etc you won’t hear the problem so much as they already sound ‘bad’ by comparison, though the distortion should still be obvious.
If it is something my end the only thing I can think of is if the old twitch was using something like HTML5 and now uses flash and my flash is out of date (for example), but that’s grabbing at straws…
Thanks