IIRC ATC have said their two-way passive speakers have two sets of terminals because it’s demanded in many, mostly non-UK, markets for biamping as much as biwiring. I do wonder if, as their popularity increases, there’s enough demand now for ATC to consider offering single terminals as an option. Just a thought.
It’s very very easy to convert them to single terminals… all connections are bolted so 15 min job. Did my 11’s and it’s worth it… might even get rid of the crimped spade terminals and solder when warranty done.
It’s a long time ago now, but I did that on the HF drivers on a pair of Mordaunt Short MS310s (after blowing one, ah, the folly of youth!), it definitely cleaned up the sound