While spectating, how to hide HUD but still hear the announcer?

Hello, I'm trying to record highlights from some games and put them up on YouTube so my friends can see them, but I'm having a problem with the announcer. If I hide the HUD, it looks clean but the announcer won't say things like Red team double kill! or Blue team Pentakill! But if I leave the HUD on I can hide everything but the little box in the corner, and that bothers me.

TL;DR - I want to hide the HUD but still hear the announcer while spectating my games.