3D imaging

Lived in room, but loved in is better!!!! Spellcheck...,

Diff + absorb + random = good, lots of variation in surfaces, textures, a loved in room is often FAR superior to the audio ph dedicated room with rack between speakers and a forest of amplifiers on the floor....

IF you want to experiment with a very affordable low TIM SS amp with gorgeous sound, try an Audionics CC2, circa 1978...

there are others, if the science of that interests you check out Dr Matti Otola papers on subject

Stereo is an illusion for sure and  audio is certainly not only science but also physchoacoustics, brain/ear are as yet inseparable... well for most...

there is that pesky brain/ear/ego bit as well

Many of us think high TIM amps don’t image well, 

for more insight on your LS 3/5a and why they are so good, check out all the work the BBC went to in creating them, lots of science in that one and some ear brain also

while not strictly an 3/5a, I have a set of modified KEF101 that are image champs...

how fun enjoy your music

also get Jim Smiths book on getting better sound

And unless you are listening in the near field, the room matters a lot.... a mix of absorption and diffraction are key ....

Actually crossovers do matter, steep slopes screw up phase and that means poor impulse response all inside the 3-5 ms “ rule “
actually electronics do matter, negative feedback also screws up time and phase and can lead to TIM, wonder what the T stands for ?
time alignment of the drivers matter
pistonic drivers matter, an out of phase cone is destroying the image information as well as screwing up frequency response
low reflection cabinets, treatment inside the cabinet AND a low reflection driver magnet are available in certain products
managing the grill edge can reduce the baffle step effect and so can managing driver directivity- not all drivers radiate off axis at same level, so reflections can be down in amplitude reducing reflections
cabinets matter
:-)
oh and how a driver stores and releases energy can be seen in the impulse and waterfall plots, pay particular attention to those mid ranges wired out of phase, panels with edge clamp issues, speakers that start negative, waterfalls that never end....
vast is a relative thing, I am just a student...