Symposium Ulta Shelf under floor standing speakers - Any Thoughts ?

Certainly worth trying. I can testify to the benefit of well thought out isolation of the speaker from the floor having recently installed the Townshend Seismic podiums under my Magico Q3s. This is more than twice the price of the similar sized Symposium offering but would have the added benefit of isolating the speaker from external vibration (as well as the speaker from the room). 

i guess my one concern having read the Symposium materials is how you level the speaker after removing the spikes as the shelf is to be used flat on the floor. For my speakers at least having them perfectly level is quite critical. The Townshend offers four point leveling

Thanks Folffreak and I have contacted Tonwshend for more information and US dealer. I like the idea of leveling as well as a thinner profile. Symposium does have products for speaker platforms that do include leveling spikes but my concern is the size / height of their platforms and raising the speaker too high.   

I use svelte shelves under my speakers, which are thinner than ultras, and I have ultras under my amp and DAC /music server.  Like any tuning device, whether it helps or hurts the sound quality is dependent on the room/system and what you are trying to achieve.

My setup is on a suspended wooden floor covered with wall-to-wall carpeting.  Speaker spikes would couple the speaker to the floor, which would act as a sounding board.  By using the svelte shelves, I got a tighter sounding bass response.  I have the speakers sitting directly on the shelves (to most effectively couple the speaker to the shelves, which in turn dissipate the energy in the core of the shelves).  In order to tilt the speaker back a bit, I use wooden shims under the front of the shelves.  It is probably best to have the svelte shelf flat on the floor, but, more importantly, the speaker bottom should be in full contact with the shelf, which I manage to do with my setup.  

By the way, I know someone who is in the business of setting up systems and he uses svelte shelves a lot under speakers and finds that in most instances it helps the sound unless the system is already overly dry sounding.

I have looked into more elaborate footers/platforms, but, not much more than a casual look.  The issue with many of them do involve leveling.  The ones with adjustable height of the feet, like the Townsends, would allow for leveling, but, I am not as sure about whether they can be used to tilt the speaker back a bit, without upsetting the spring/suspension mechanism which probably works best with the speaker completely level. 

I didn't find a US dealer for the Townshend podiums but had no problems buying them direct from the UK. They are made to order in the UK anyway and will take about 6-8 weeks to get to you. Cost will be $2000 plus depending on the size you need. More details on this thread
https://forum.audiogon.com/discussions/speaker-isolation-experience-with-townshend-seismic-isolation-podium

To Larryi's question on tilt you can get a small degree of tilt but probably would not want to push it too far