ST215W Exhaust Muffler noise

[camof11]

About a week ago my standard exhaust starting making a funny noise. Sounds like something is loose inside and restricting flow. Car is drives fine.
Only heard in the last Backbox section.

Also I had a quick look at it this morning and i saw a cable system hooked up to one of the two tailpipes. Is this standard? Looks standard. Wheres the other end go to? Does it open on full throttle or something?

Edit, Just searched and found that it is a standard cable system, my butterfly valve may be stuffed?

[Lac]

Sounds like it, it goes up inside the panels of the car in the boot. Go get a nice new muffler and just tuck the wire into the boot well. thats what i did.