Subwoofer for "seamless" integration with Zu Druid


I've had a pair of Zu Druid Mk-iv's for about 3 months now. I'm really digging them, but miss the lower octaves. I don't know much about subwoofer design or manufacturers. Anything that would give me solid response down to 30hz (or even lower without sacrificing speed) but still be fast and tight.

What is the best design for integrating into speakers such as the Zu's (sealed, ported, with passive driver, etc.) and what brands/models should I be looking at? I'd like to spend no more than $1,000.

The REL's are reviewed well, and the Zu Method and Mini Method seem an obvious choice, but aren't manufactured anymore and are scarce on audiogon.
fargel
You need a REL Britania series B2,or B3 you can find these used at very nice prices..it is the only way to get seemless integration with your Druids. Check it out.

I am very familiar with the Druids, having listened to them at a friends house. He bought them new, and they took many hundreds of hours to fully break in, with bass being the most noticeable during the process. His bass is so good, some have even asked, "Where's the subwoofer?"

Have you experimented with the gap between the bottom of the speaker and the floor. This definitely affects the bass response.

Also, the impedance curves of the Druid and Vandersteen are quite different. A speaker cable can work great with one speaker and not so well with another. Myself and a few other friends have experienced this with various speakers and cables.

Have you done anything with your power, dedicated lines, upgraded outlet, power conditioner?

One thing to keep in mind is that the sound of Zu speakers is extremely coherent, and that will be compromised when you add a subwoofer.

BTW, the MF A308, great amp, I have one as well.
A good sub will NOT compromise the coherency of main speakers if used properly, especially if you blend it in where the main speaker starts losing its ability to make bass, and you keep the sub at a reasonable level. Low frequencies are more than simply bass notes...they are part of the ambience of real music in the real world. Once you have a good sub dialed in everything gets better...you feel better about the world, food tastes better, and you personally become more likeable and slightly better looking.
My experience may not be very relevant since my Druids are somewhat modified. Anyway, I have had great success using two JL Fathom f110 with my Druids. Features such as inbuilt auto dsp, phase, and roll-off options provided by these subs makes it fairly easy to achieve good integration. I use two because I am a bass-freak but one should be adequate and can be acquired used at your budget.