Adding items to an existing stack plays sound effect regardless of volume setting

[true pivot]

If you take an item and combine it into an existing stack, either in your inventory or in your bank, the sound effect plays, even if you have the volume off

This happens when the item gets consumed into the existing stack, even if you manually click an item from a monster corpse and add it to your items in your normal inventory, however it doesn't happen when you click "Loot all" and the item merges into your existing stack