This problem seems to be opposite of any other wine sound problems, sound works beautifully in World of Warcraft under wine, but it remove all audio output for other programs such as Mangler and the system sound test program. I have tried starting programs before and after WoW to see if that will make the audio work but that doesn't help, I'm all out of ideas.
I was trying to figure out what was causing this issue for me and the post above about "Disable background info" had me thinking about in-game sounds. The setting was actually called "Enable sounds in background" for me (version 4.3.4 at the time), though that didn't fix it. I copied this installation from my Windows install and so all the settings were the same. I noticed I had my sound channels set to "High (64)" and when I swapped to "Low (24)" immediately the sound buffered in Mangler all played at once. I still left "Use Hardware" checked, and haven't had issues so far but I haven't done extensive testing. Hope this helps!