Don't know if I should laugh or cry.
My son has the same problem on his HOX and while trying to download "soundabout" I noticed he had it installed...
So instead of installing or upgrading it, I simply removed this app you recommended and his speaker works perfectly fine now!!!
Well, thanks for mentioning this app in your post then ;-)
OK. Here is how I accidentally fixed this issue on my HTC One S: At the same time, press the volume down button AND the power button briefly. This got my sound going again after a frustrating day. Good luck!!