Look in the link in my sig, the system with the black turn table, the subs are less than a foot away and I don't have any issues, but I mounted the subs on sand filled cast iron stands which may be helping... I would not try to fix a problem that you don't have yet, set it up in your ideal location and see how it goes, if it is an issue, then visit the idea of isolating it and fixing the issues... Some times its as easy as putting some isolation blocks under the turntable...