I have to agree with most of what has been already stated in this thread. I also agree with Tubegroover "The greater the resolution, the better the effect". If you speakers are up against the wall, probably not going to do it that well. To get a black background and added resolution, that will most likely come from your preamp. In building preamps, I start with filtering the AC with a filter choke. That is the start of having what most call a black background. It removes the C nosie that most don't know is there until you filter the ac. That helps music come out of your speakers from nowhere and everywhere. Most preamps use capacitors. Everyone of them has a sound. I use output transformers which to my ears makes a big difference to using a capacitor. I have not heard a capacitor that can separate vocals and instruments in their own space or at least to the degree I am hearing from output transformers. There will be many audiophiles who may disagree but I experimented with so many design options and that is my overall conclusion. The output transformers just let the music flow and I gained much more resolution (soundstage height, left to right separation and front to back). Then I swapped out the volume control for TVCs, which do not use resistors so that added more resolution. Last was chassis design materials. So as you can see, so much goes into resolution to provide the "holographic" soundstage. I can tell you that my preamp will make any system more holographic. Having the black barckground and the separation in all dimensions is what did it for me.
Happy Listening.
Happy Listening.