Quoted from Vader77:For that sub I think you do need the adapter. Most subs I've seen have the speaker level input so you wouldn't need the adapter. You can connect both games to 1 sub but you'd need 2 adapters
This is correct. Since the sub in the photo only has line level inputs, you will either need a speaker level -> line level adapter, or something like the Pinnovators kit which taps into the pre-amplified signal.