Ceramic insulator cone under phono stage shocker!

@three_easy_payments,

To me your situation suggests that your (rack, I assume) isn’t effectively decoupled from the floor or surroundings.

@slaw

I’ve actually considered the exact same thing and I suspect you’re right. My rack sits quite close to one of the speakers and the cones are probably dissipating some energy transferred from the floor or even sound reflections from a nearby corner. I have a Symposium rack with spikes that sit on four Precision couplers (maybe I should be using dampening pads and not couplers?) and I use Gaia III feet under my speakers but together they may not be enough to keep the seismic out of the rack. Cones pointing up may be the perfect workaround for me as it would be very difficult moving the rack considerably farther from the speaker. I have a couple of GIK tri-traps on order, one of which will go in the corner 4-5 feet behind the rack - this may helps as well. I have a 24x48 absorber wall panel behind the rack but the corner is untreated.

Thanks for weighing in.

The precision couples are doing just as they are suppose to....coupling your rack to the floor...not decoupling thereby exacerbating the issue, IMO.

@slaw Agreed. I’m going to look into something that acts as a decoupler that the rack feet can sit on. I'm open to any suggestions from folks.  I'm using the foot configuration at the bottom of this link page.
http://symposiumusa.com/pcouplers.html

@three_easy_payments,

If you don’t mind my asking, how tall is the Symposium rack and what tt are you using?

Remember that acoustic "feedback" for lack of a better term, accentuates the vibrations components see. Is your floor a slab? If not, it should be braced underneath.