Chatbox notification sounds are much quieter and easier to miss on Steam Audio. I've been told by multiple people that they didn't realize I was sending messages since Steam Audio launched to Live.

I've attached 2 videos showcasing the difference, both the sender and the camera are in the exact same position, and it's clear that the Steam Audio one is quieter.

The first video is ONSP (using the un-updated 3p-beta branch), the second one is Steam Audio on Live (build 1768).