The Settings menu inside the client displays the option to (check/uncheck) sound effects, as well as set the volume of the sound effects.
Unfortunately, the sound effects options here don't edit the sound effects that are triggered during the new Hextech Crafting feature.
I believe that the current situation should not be the case. Could this please be changed? It's a fairly loud sound, and it is hard to balance with other programs on my computer that play audio too, seeing as how I have to change my entire computer's volume.