I use _audio.csc and it works ok and is fairly easy to setup without any scripting.
Copy the header and an ambient alias from a zombie sound csv into a new csv. Electric or wind sounds are good examples to start with
Replace path with your sound. Convert your sound. Copy _audio.csc into your mods/mapname/clientscripts folder.
Open audio csc and there is 3 getstructarray parts.
They use a script_label kvp on script_ structs
Emitter
Looper
Random
And
Script_sound kvp for the sounds name.
I do all my sounds with script_label random and looper because emitters didn't work the way I expected.