Looking for some input from the forum. I have a dedicated theater room. Have just upgraded front speaker to M100s, center speaker to the VP180 and have the new QS10s on order. I have two of the old EP500s (eight years old). My question is it worth upgrading to the new EP500 sub-woofers. The sub-woofers sound good and I don't know if there would be that much of an improvement in the sound. Any and all thoughts welcomed.

By upgrading we get your old subs....win win. Lol.

The new one is sealed so it will sound tighter due to less distortion - and no port chuffing. I believe it reaches a bit lower too. The new ones don't have a brick wall filter above the cross-over frequency so they integrate better with the rest of the speakers. Yours might not have a brick wall filter either. I can't remember when Axiom changed this aspect of the response curve. As to whether or not you will hear a difference, it depends on how discerning a listener you are.

That brick wall came out v2 I believe.

Just picked up an EP400 (V1 I think) for $130. Using it with an EP500V4 in a 7.2 system. I like it. The two get along very well together.

I mean it was removed in v2 .....lol