They aren't a perfect fit unfortunately but you can get them to fit safely and securely if you screw in the speaker loosely, tilt the speaker, plug in the cord from the subwoofer, tilt the speaker back, and then screw it in till it's

A perfect fit for my Polk Audio surround sound speakers

First, it was not clear how the speaker fit tight.

Perfect fit and easy to attach.

It ended up being the perfect fit behind my couch

and they were perfect fit.

Great fit for my speakers and easy to mount.

I all ready have see previous note