Hanging Audio Rack?

I tried it and found some beneficial effects for resolution, but essentially whatever you use to suspend the rack ends up affecting the sound significantly - a bit like the twanging of a guitar string it depends on the stretchiness, rigidity and tension it is under as to the effect you get. By funneling resonances into one region you get significant smeering of that region. At a highish frequency you will get an irritating ringing effect, and at a lower frequency then PRAT suffers to some degree, in a very similar way as bladders cause the same effect.

What you need is a stable rack that is free from vibrations. Hanging from the ceiling has two potential problems. The first is the length that you are hanging which will determine a low frequency oscillation--generally outside the audible frequency range. However it can carry harmonics from other vibrations--which is one reason you are likely to find so much variation in people's opinions of this. For example if a particular transport has an internal oscillation at say 400Hz and this excites one of the potential harmonics of the hanging stand--it could (and probably would) make things worse. The second thing is what you are hanging it from. If the ceiling is a room above and the floor is concrete--well the floor is going to be more stable and have less vibrations. In any case, predictability is on attaching to something rigid and then working with isolation or vibration tweaks--like vibrapods and tiptoes. You could get better results with hanging--but it would take quite a bit of experimentation--and if you read the thread on why do systems sound better at some times than others--you might think this level of experimentation would be difficult to say the least.

So then, what is the best possible floor for a rack to sit on? Let's say we were designing from scratch. I've always found it hard to believe that a wood floor system with it's giant diaphram is good, and concrete retains too much energy. In the perfect world, what would your set-up look like from earth up and why?

I have considered this, although it would be a huge commitment. Beyond traditional pier and beam construction, each piece of sensitive equipment would get it's own individual concrete pedestal, going deep into the earth, below the house. The rest of the living/listening area would be constructed in the normal fashion. Finishing out the pedestals and the living area floor to the same height would be tricky. Then a seal between the two individual surfaces would be needed to fill the void . With the equipment on their own individual solid concrete blocks, the entire house would be de coupled from the equipment. I know one high end manufacturer that uses this design in his home. Unfortunately I have not had the pleasure to visit and view the project myself.

Jadem6 asks a very good question. I'll give you what I've done--is it the best--no. I have a concrete slab with standard 2x4 framing. The audioroom floor is a floating (pergo) floor with an oriental rug covering 3/4 of it. All audio racks are build outward from the framing. The turntable "floats" on oak cantilevers with 150 lb granite slab on the oak. All components are in the adjacent room with the cabinet cantilevered from the wall joists. The shelving is corrian--I've found it has very little resonance (be careful here--other solid surface material does have very bad resonant signatures). There is certainly better shelving material--and I've started to experiment with a few things.

What would be better? Well a dedicated concrete slab that was separate from the audio room floor. Some people have used dedicated slabs for the speakers as well. This almost insures decoupling of the speaker vibration to the room (as well as equipment). Obviously, it's pretty impracticle--but if you were building a house and cost no object audio room--that would probably be the way to go.