SteamOS defaults to using HDMI sound, which will only work when using HDMI to plug into a TV with speakers. To change this, click on the Settings button, then Audio. Click the Reconfigure Audio button. Select the appropriate audio output (usually Build-in Audio).
There have been similar reports with in game audio with pulse. The fixes below seemed to have helped the majority of customers. Please give them a try and let me know if they work for you as well or not.
Run pulseaudio in verbose mode. Modify the default load in /etc/pulse/daemon.conf to enable tsched and tweak the buffer size and watermark:
load-module module-alsa-card device_id=0 tsched=true tsched_buffer_size=1048576 tsched_buffer_watermark=262144
After restarting pulseaudio, the stuttering is now gone.
Sound was fixed by editing my /etc/pulse/daemon.conf file
Change the "default-fragment-size-msec" value to 5