As a pratical matter concrete is not resonant. So long as your speakers are connected directly to the concrete via any type of well constructed and effective spikes, i.e. those that effectively piece carpet and pad and support you speakers firmly, you've done as much as you can do. IMHO, in your situation the fine gradiations in support spike's construction, beyond good support, is sales hype. At least that has been my experience from experimentation and I know of no solid engineering support for products beyond those that can support your speakers and make a good solid connection.
Speaker Footer Advise Please
I am getting near the end of the road in terms of tuning my system. I feel that one of the last truly big steps I can make will come when I carefully decouple my speakers from my slap concrete floor. What I am looking for is practical experience and advice from people who have performed just this. As a side what were your experiences along the way and what did you settle on and why. My speakers are Wilson Watt Puppies 5.1 and T+A amp and preamp so my system is dynamic to say the least. I'm looking for that last bit of separation of sound field from my speakers and would like to see if I can tighten up my low frequencies from what is now the tightest bass I have ever heard.
Many thanks in advance.
Many thanks in advance.