If you have “choppy” audio in Gnome on FreeBSD, it’s likely caused by PulseAudio. My definition of choppy audio is where you get very brief gaps of silence as you play audio – a sort of slow crackle.
As root, edit the file /usr/local/etc/pulse/daemon.conf and go to the bottom of the file. There are 2 lines currently hashed out, modify them to read:
default-fragments = 8
default-fragment-size-msec = 5
then you need to restart pulseaudio. As the username you have logged into Gnome with (not root!), type:
This should sort things for you (or at least, it did for me)