The best Subwoofer

................................................................ none at all.
I've never heard an aftermarket sub completely and coherently integrate with the primaries and dissappear.
A few have come close but none totally convincing to my ears.
The most satisfying have tended to be dedicated subwoofer modules built by the loudspeaker manufacturer for a single specific product(ex- Neat Gravitas with Petite monitors,etc.)

I have just ended my search for the best sub. I have listened to almost everything out there. If price is no object, the best sub is the new Wilson Audio's Watch Dog. I heard it with the Wilson Cubs II, which I own, and was a perfect match. If price is an object, it would be the new Revel 15B. The difference between the Revel 15B and the Watch Dog; sometimes when you were listening to the Revel 15B you knew you had the sub on, with the Watch Dog you never knew it was there. This sub has no limitations. If you have fast speakers than either of these subs are outstanding. With the Watch Dog, I watched scenes from Gladiator, U-571, Patriot, Braveheart and T2, and listened to more music then I care to list and it's impressive. My wife will know I have added a new piece of equipment in a couple of weeks when I play either Dark Side of the Moon or The Wall. If you hear about a house falling down in Southern California, it will be mine.

The best blend (other than the Wilson WAMM with its subwoofer) that I have heard was the Muse 18 to augment the Hales Signature 2 (out of production now). The blend was PERFECT.

I have a hard time believing that the REL Storm III would not be mentioned. I have added two Rel Storm III's to complement my Spendor SP-100 Speakers, and I have been astonished with the result.

The REL's have the adjustability that many Sub's lack IMHO.

David