As of patch 4.0.6 its once again possible to only hear addon sounds, just enable sounds and put your Master Volume up.
If you cant hear sounds from an addon that way, inform the addon author to add a 2nd param to the playsound(file) function with value "Master" this will play the sound over Master channel.
Looking like this: PlaySound("sound","Master")
Currently addon sounds only working if you enable at least Sound Effects, which means you hear all the standard sounds too all the time, many people including myself don't like that but wanna hear addon notification sounds.
So i wrote this addon as a temporary solution until Blizzard fix that.
The addon will enable sounds for a a limited duration when a addon plays a sound and after that disable the sound again, its standard set to 2 seconds but you can change it to a value between 1 and 10 seconds in the interface options.
During that time you will hear other in-game sounds as well nothing to do about that, but at least you wont hear them as long no addon wanna play a sound.
Because the addon cannot differ if a 3rd party addon or one of the Blizzard addons wanna play a sound, the addon includes a ignore list with all sounds the Blizzard addons play located in "AddonSoundIgnore.lua".
If one of your addons play those files too and you dont want to ignore them open that file find the right sound and replace the 1 with a 0.
If you have set a Master Volume and/or Sound Volume it will use that settings, if you have either of them on mute it will be turned to 100% during the play and then back to 0%.
You need to have at least Enable Sound checked all other can be off.
If you change your sound settings you need to do a /reload or the addon will change to your old settings after a sound was played.
-I changed it back to a normal hook as it was in version 0.1, because this allows to hear even short sounds, but also added a option to let it work with a secure hook (as it worked in version 0.2) for those having tainting issues
-changed the hook to a secure one to solve the taint issuses occuring sometimes for some people (i am not sure if even my addon were producing that, if you still get it by another addon i would like to know)
-added the playsoundkitid function