Coupling vs Decoupling


I’m new to this forum and have been doing much reading. I’m aware working with the room and equipment can produce dramatic changes in sound. One topic I’m lost with is coupling vs decoupling. When, where and how to apply each method to produce the best outcome?  

My current system is KEF R900 towers with matching center, R600C and surrounds, R300 and a pair of JL E112 subs flanking a Sony A1E TV.  The room is a bonus room approx 24’ x 14’ with all centered on the 14’ wall. 

Currently the towers are equipped with spiked plinths and subs sit directly on the carpet with their OE feet.  Any feedback about how to best manage acoustic vibrations and when/where to apply coupling or decoupling methods is greatly appreciated. 
jdeickhoff
Generally speaking, a combination of coupling and decoupling achieves the best results. Example, to decouple/isolate a component use mass-on-spring technique. Then use very hard cones or spikes to couple the component to the iso stand AND to couple the stand itself to the floor or rack. This coupling allows residual vibration to exit the iso system pronto. Problem solved!
I appreciate the responses so far. 

@hifiman5 - the floor is a second story carpeted wood floor in a bonus room above the garage. The TV and components sit directly on a wood console, that is a leftover from pre-system days. Perhaps this is a great reason to upgrade!

@blueranger - thank you for the video. I’m very surprised the difference it made, even viewing from my iPad. I have looked at IsoAcoustics products recently. I’m curious which products and applications could produce best results. Do you have any personal experience with them?

@geoffkait - the idea of a combination to produce ideal results makes sense and is intriguing. Do you have personal experience with a product you’d recommend?