Add the speaker icon
http://image.prntscr.com/image/50610da2378b4b2da5d37541ce070d7e.png
We have a bullhorn icon: https://materialdesignicons.com/icon/bullhorn
I need a bullhorn-outline
I believe making the bullhorn that we already have into an outline wouldn't work visually. Look at the smallest one, and imagine it as an outline.
I think this icon might need to be resized slightly by 2px width. Right now it looks "off". Just something to look into.
Here is an outlined version with the same/current dimensions of the current bullhorn.

I think we need to increase the width by 2px. The icon is too narrow when used next to others right now.
Done.
Most helpful comment
Based on #3463, here is a redesigned
bullhorn-outlineAsset 4.zip