Rel storm III or Stadium III.

I have owned, and liked the one version older 18" Velodyne. It's a great sub for HT. It's a great sub period. But, when it comes to integration with your main two channel speakers for two channel music listening, go REL and don't bother to look back. I am now a happy Stentor owner (sold the Velo). The way the Stentor seemlessly integrates with my already full range speakers is amazing.

I run my big front speakers full range for HT, I only need that sub for the .1 material, and the REL provides seperate inputs and levels for both.

You have to understand your buget. Cycle per cycle the REL is a touch more expensive than the 18" Velo. The REL's higher price is commesurate with its higher performance, for sure. If the budget is a higher priority than music, go Velo. If music comes first, go REL.

The Rel is old tech. Check the the Velodyne website and read about seemless intergration. It has a built in computerized room correction that is diplayed on screen. First do the sweeps from 15 to 200htz and see what your main speakers are doing in the room. Second,bump up the volume on the Velodyne sub. until it is close to where you want it. Third use the EQ to flatten out the room responce.
This is nothing like any other sub.

The REL maybe "old tech", in how it accomplishes its goal. Let's judge equipment based on how successful the equipment is in acheiving its intended purpose.

I have heard the REL. Have you heard the new DD series?

I have only critically listened to (and owned) the DD's 18" predecesor. Unfortuneately, I don't have the opportunity to listen to the new 18" DD, especially now that you have my curiousity piqued. I do not feel that that previous Velo model integrated or performed as well as the Stentor III which replaces it.

But as you point out, this is not the new DD series, which I admit I have not listened to.