Has anyone had experiences good or bad with speaker isolation or isolation in general ?

i have been enjoying buying and listening to hifi for some 35 years now and have seen many items come and go.I have also been interested in the audio cable discussions and i agree that cables do make a difference how much of a difference is a very individual, and a system dependent situation. There has been nothing that has got me so excited and improved the sound of my system that has ever made me want to really share it with fellow audiophiles until i started to try various isolation products.With so much choice from affordable to very expensive i found the hole subject very confusing and i did not know where to start. After trying lots of various products all shapes and sizes with very different results i decided to read reviews which is something i do not usually do to get some advise.I read a review on the Townshend audio seismic podiums they are isolation platforms that go under your speakers .This company is very famous for isolation ideas and have been around some 50 years based here in the UK they also had a factory in the USA back in the 1980s. I contacted Nick at Emporium hifi  and he agreed to install a pair for me so i could have a listen. My speakers are sound-lab dynastats which i use in quite a small room but with the adjustments give a nice sound. After installing the podiums we both sat down with jaws hitting the floor these podium things completely transformed the sound of my system to absolute perfection. After all this time trying various products under my equipment i have now isolated my speakers and the sound quality is exactly what i believe we all are chasing, my sound-labs are now transparent no more bass problems i have just got one big 3D sound stage the dynastats are now very open with deeper much better bass everything is perfect. I now believe isolating your loudspeakers is the first port of call i was so impressed by the Townshend audio seismic products i now sell them as i have never come across anything that has given my system such a great upgrade , the sound is the same as before but now its just so much better its playing deeper bass but tighter much more resolution and no boom , the midrange is so much more human sounding realistic and spacious with the top end so refined and perfect , is anyone using podiums and had the same experiences i would love to hear from you thank you john 
If decoupling, and I mean competent decoupling, didn't work and and didn't keep most seismic type vibrations from getting up into the electronics then LIGO - long distance interferometer gravity wave observation - would not have been successful last year in detecting and observing gravity waves. LIGO would have done so a long time ago if it could but the sensitivity of the experiment required development of exceptionally robust isolation systems.

As has been pointed out already, resonant frequencies of cartridge, tonearm, platter of turntables as well as the resonant frequency of the laser assembly (spring mounted!) of CD players and the Fr of all the various electronic elements in components require relatively robust isolation devices, too. That's precisely why audiophiles discover that more expensive iso systems are superior to the usual DIY inner tubes and tennis balls. It's because their resonant frequencies are much lower and therefore more effective at 10-12Hz or wherever.
@hifiman5  Buddhism is my religion. The Buddha said to try things for yourself and determine their worth and take nobody's word for anything. I simply haven't been able to demonstrate to myself that decoupling speakers produces benefits on any scale. I'm a bit curious what people are hearing because what people here are trying to accomplish is exactly the opposite of what I've tried to do, and what I thought was conventional wisdom.

The word "floating" can be misinterpreted. Floating on a carpet or something that’s not rigid is not the same thing as "floating" on springs or a magnetic levitation system - if one were feasible for speakers which it’s probably NOT. It’s the low pass mechanical filter characteristic of mass-on-spring isolation systems that is responsible for the improvement to the sound. And the fact that the lowest frequency of speaker cabinet vibrations is sufficiently high, let’s say 25Hz or 30 Hz if you’re lucky, that % of transmission to the floor is very very low, based on the resonant frequency Fr of the mass on spring system of the speakers and springs, let's say 3Hz.

Back in the day, in the mid 80's or so, Mod Squad came out with Tip Toes.  For about $7 for a 1.5" metal triangle cone that looked like a large silver Hershey Kiss, I had them under my amp, preamp, TT and speakers.  They were amazing and made such a huge sonic difference.  The threaded ones on my TT were like $10 each.

Then other mnfr's started catching on and things went nuts.  The same cones were now $50-75 each or more.  Were they any better then the $7 ones, Don't know, I never listened to the more expensive ones, but I had my doubts.  I gave them to a friend to try and never got them back.

Nowadays, I have very small light mini-monitors.  Instead of spikes, I went to Lowe's and have hard rubber stoppers under my speakers that cost me like $1.50-$2 each and use 3/speaker.  For heavier larger monitors, I bought larger cork stoppers under each speaker.  I think they sound great lifted up an inch or so off the floor or shelf.  

Spikes may sound better, but for me, it's like splitting hairs.  I'm quite content to spend a few bucks on hard rubber stoppers and it seems to make a huge difference and looks very nice as well.  

"Back in the day, in the mid 80’s or so, Mod Squad came out with Tip Toes. For about $7 for a 1.5" metal triangle cone that looked like a large silver Hershey Kiss, I had them under my amp, preamp, TT and speakers. They were amazing and made such a huge sonic difference. The threaded ones on my TT were like $10 each.

Then other mnfr’s started catching on and things went nuts. The same cones were now $50-75 each or more. Were they any better then the $7 ones, Don’t know, I never listened to the more expensive ones, but I had my doubts. I gave them to a friend to try and never got them back."

This hobby has a lot of examples of evolution of the species. Cones and footers are a good example of how the early Tip Toes evolved into a whole industry. However where we disagree is what you are getting when you purchase footers or cones that are more expensive than the aluminum Tip Toes. Materials, geometry/shape and expense do play a role in the sound. Let me briefly summarize my results with years of experimenting with footers and cones. (Cones should always be points down no matter what anyone says.)

The best cones are made of the hardest materials, aluminum and steel are pretty good, relatively speaking, brass and carbon fiber not so good. The best by far are the NASA grade ceramic Super DH (diamond hardness) cones from Golden Sound. And although they are the same basic size/weight the Super DH Cones are superior sonically to the Jumbo DH Cones, the only difference being shape. The Super DH Cones have a shape very much like a ballistic missile. Even the smaller sizes of DH Cones are superior to almost everything else! Even to the excellent Marigo cones, the ones made with diamond dust, and the $600 Goldmund cones. I did my experiments with a great many types of cones for use with my Nimbus Sub Hertz isolation platform. When used with isolation devices differences in cones are VERY obvious, the better ones being much more open and dynamic and natural. So, the progression of cones from the early days to more modern times is similar to other audio progressions, fuses, cables, isolation, what have you. Thus, it’s a long long way from Tip Toes to Super DH Cones. It’s a long way to Tipperary.