Subwoofer Isolation, what do you think...


I just got this big honking subwoofer, a DD-18 Velodyne. I've a ceramic tile over concrete floor. I also have a nice turntable in close proximity to the only WAF approved site for the big honker. Anyone have any feeling for if the adjustable feet that came with the DD-18 are enough or should I replace them with cones or something else? I always use the sub even with the vinyl as it adds so much depth to everything. I can't say my turntable's stand is very good, it isn't but I'm working on finding something good (and affordable!). I am concerned though with this big thing so close... maybe within four feet.
Thanks People!
sailfishben
The problems you may experience are more likely to be with airborne vibrations. I don't think that you will benefit much from further floor isolation under your sub. Your turntable, perhaps. Generally it is best to place your turntable (and other components) in a spot in your room which has a bass null or at least a neutral zone to minimize the effect of airborne vibs.
I agree with Newbee about not isolating under your sub.
Also agree about turntable location.

If you would prefer upscale feet for your sub, then there are a number of choices. They can be of benefit in reducing unwanted vibrational effects in the sub.

Disclaimer: I work for a company which produces Audiopoints, a vibration management foot system.
I had a 2" thick piece of limestone cut and then used spikes for the sub onto the stone. Tightened up the low end response; ie, cleaner sounding, not muddy any longer.
I had the same problems with my Velodyne FSR1800X Subwoofer next to my Projector stand shaking the pj. I tried Aurio 1.2's first and then went to Aurio Pro's to Decouple my Subwoofer from my tile floor. I also went through that same process to float my 17lb projector to take it to the next level. I am going to do a shootout with my Sistrum SP-4 stand under the subwoofer again which tightened up my sub considerably in the next month once I stabilize the changes in my system. I use 2 sistrum full racks for my video and audio system.
I can't say I've a problem but I'm more wondering what other's do, if anything, to their subs in this situation. The built-in leveling feet are great and make a solid mount but...