Still inside the cabinet but it does have a port to let the pressure out on the back side, so not totally enclosed .. I'd *guess* it is a little tighter that way, but haven't experimented with an open cone like you did .. neat idea and variation you had

As I'm sure you noticed, this method seems to 'move a lot of air' in the end mix from the BD
you 'hear' it, but you can also 'feel' it (more in your chest than in your ears) on a decent system

I hate seeing a BD with a blanket in it, just a personal pet peave

I do not work here, but the benefits are still awesome
Make your sound your own!