Mute timer sound

[gitgitchinchin]

First of all, thanks for this tool. It rocks! I specially appreciate the ability to play brown noise during a pomodoro session. It just puts me right in focus mode. However, sometimes part of my research is to listen to a youtube video. I couldn't find a way to mute the brown noise without disabling the timer. I tried pausing the timer, changing the settings and resuming the timer but it doesn't pick up the new settings. Would be great to have the ability to mute the sound while timer is running.