what sub would be best? B&W, MARTIN LOGAN, DEFTEC

I've heard some Martin Logan subs and was very impressed with their ability to augment the bottom end without drawing attention to themselves. It stands to reason that a company that creates subs to blend with electrostatics is going to pay careful attention to transient response and response curves that blend with the mains. I don't think I've heard the Dynamo 700 specifically.

However, this review looks like it's a unit worthy of consideration too.

Last week I heard the B&W PV1D, which at $1800 is a lot more money, but it *is* fabulous. AFAIK I haven't heard the ASW610 (200W, 1X10"), but the reviews seem favorable.

I have a friend that has this SVS sealed box 12" sub. He mates it with Magnepans. Since it's smack dab in your price range (including free shipping) it should be worth a look. Reviews are very favorable and purchase includes a 45-day trial period and 5-year warranty.

If you get a 10" Logan, buy the earlier Dynamos used, it's what I have. They're sealed rather than ported and by all accounts more accurate than the current model. For what you'll save buying used, for the money you can get two, always better sounding than one sub. I saw one for sale the other day at a very attractive price, it may still be up.

At the opposite extreme, consider this, it's more expensive at $850 but highly regarded and it will take you all the way down to 20 Hz with good output and servo control:

http://www.ascendacoustics.com/pages/products/subs/f12se.html

Check out the RSL Speedwoofer 10!!

Another one you should look at is the paradigm Monitor 10. Goes for around $850. This small woofer goes down to 17hz. I'm actually waiting for mine to arrive.