Need help

I had the same issue and my system is also on the second floor. I was able to eliminate the issue by using a Townsend Audio Siesmic platform.  

Sounds like a Rumble filter issue ...

https://www.svsound.com/products/soundpath-subwoofer-isolation-system

Target, or other, wall-mount TT shelf. Screw directly into the wall studs. If you still need more isolation after that, try the springs, pods, dots, etc...

If Herbies will work, great. I have my doubts but you never know. What definitely will work is a two-pronged approach: springs under speakers (not just the subs) with springs and added mass under the turntable. I was surprised at the improvement putting springs under mine. 

You can buy plain springs on-line real cheap. But its a lot of work because they need to be sized correctly so that the springs are about half way compressed under load. Nobsound springs on Amazon are only $30 and very effective under both speakers and turntables. Also amp, CD, phono stage. Use them everywhere.  

By far the best however are Townshend Pods. These also need to be sized to the component but they make this a whole lot easier. I was extremely impressed with the improvement under my turntable and amp. Had almost the exact same problem as yours, completely eliminated and even made everything a whole lot better. https://systems.audiogon.com/systems/8367

@lenmc2964,

I would start off with 4 dots underneath your RP3. I am using 3 dots for my SME 15. Just looked up your system, it appears you’ve already addressed the isolation underneath the subs 👍

Your room is very similar to mine (great decor and choice of electronics), I am using Auralex SubDude Acoustic Isolation Platforms.

Agree with trying Herbies, and you’d probably also benefit from putting the subs on some footers from SVS, Herbies, etc. as they’ll probably improve your subs’ performance in addition to quelling more vibration.  Best of luck. 

Or could I get 6 under it

lalitk 4 dots for the Rega RP3

flat black round your dead on. House is just as you describe.

“when I use the turntable the subs go crazy vibrate the floor bad I can’t turn up the volume at all”

I had the same problem where I couldn’t turn up the volume on my TT. My suggestion would be to try the Herbie’s large soft fat dots. I couldn’t believe the improvement, they’ve effectively blocked all the vibrations. My audio room is located on the 3rd floor :-)

https://herbiesaudiolab.com/collections/component-isolation/products/soft-fat-dot?variant=1264510543...

Having owned a couple of Texas homes, I can well imagine your problem.  Large house on a concrete slab, no basement, wooden frame with brick or stone facade, plywood floor on the second floor with a large upstairs second family room.  Am I close?   If you want to continue to play vinyl and get the best sound, place your system on the first floor slab. That’s what I ended up doing. Good luck.

Have you thought of putting the turntable on a shelf mounted to the wall? That's what I did when floor vibration was affecting mine. At that time (20 yr ago), Target made a reasonably priced wall shelf.