Are Isoberic Subs any good such as James 10SX?

I believe your right. Sorry for the confusion.

I think you are talking about the EMB-1000... the one with the metal passive radiator. The model I'm talking about has just a 4" port exposed with two internal woofers.

Bruce

I've listened to the sub you mentioned and I have to say I was very impressed at how good it sounded for a small and relatively inexpensive package. Yes, there are better subs, but I think for that size and money they have really raised the bar. I can say that I have listened to at least 2 other comparably priced and sized subs that have a very good reputation. I won't mention the names, but let's just say they have some catching up to do. The isobarik loading allows the exposed driver to move far more efficiently and even more important stop more efficiently. I'm not sure about "just exposing the port"--that doesn't seem correct to me, but I am not that familiar with the setup protocol for this sub.