What is sound floor

Do you mean "noise floor" by any chance? I'm not going to explain it well, but it's a term used to describe the background noise of the recording. For example, it might refer to the noise that a microphone preamp makes, tape hiss on an analog recording, static on an LP, etc. A digital recording made with excellent mics and preamps should have a much lower noise floor than a recording made on a cassette player with a cheap Radio Shack mic. Some components also add noise when playing...certain turntables, certain tubes, transformers, etc. The lower the noise floor, the more the actual instruments and voices stand out against the background.

As far as the stone slabs go...your guess is as good as mine. People do it to dampen the vibrations, but I have never tried it. I think it's one of those things that would work for some and not for others. I suppose it couldn't hurt...or could it?

When someone says that a change to their system lowered the noise floor they are saying they heard more low level detail emerge from the general murk that lives within the reproduced sound. The noise that is not correlated with the music is not usually the issue, it is the stuff that is correlated with the music that does the most damage to our ability to hear the more fine details.

I don't find weighing components down improves the sound at all. It can take out peaky resonances but causes gross time smeering which robs the music of its PRAT (pace, rhythm and timing), which is that thing that makes you want to move with the music. Instead you are best to isolate equipment from vibrations by supporting it with light and rigid structures (eg. welded steel racks, spiked to the ground and with spikes supporting the shelves), and then to have some form of damping of the shelf. If you are going to damp equipment then it is best to use a damping sheet. Sheer weight is not the way to go from my experience (I have travelled that path).

Gosh, Redkiwi, isn't our life complicated. I use a 25kg iron weight on each of the output transformers of my Jadis 500, also one each of the same heftyness on the Spectral 360's and one on my DAC. Cannot say that my music is without PRAT and I feel, that I would notice GROSS time smearings and this especially in music which I am familiar with from live events. But all the same. I will go into this again and listen with and without weighing the components down and report. Cheerio