How to turn off sound on the launcher?

In the patch to v4.0, the launcher now makes a VERY loud bang noise when you click the Play button. I sometimes play later at night with other people within hearing range, and this is something of an issue. Obviously, I could disable the volume on my computer when I click it and then re-enable it, but that seems rather clunky. So, is there a way to turn all sound off in the launcher screen? I don't want any sounds notifying me of downloads, and I ESPECIALLY don't want the giant bang from clicking Play. I have already looked at all of the menu options on the launcher, and there's none that disable sound on the launcher.

Thanks for any suggestions.