Speakers that have holographic imaging on vocals..

electronics do play a role..but even with my Spicas and an older SX series Pioneer receiver...imaging did not improve with either a musical fidelity or arcam amp...there was more detail and better bass control...but 3-d imaging was obtainable with every amp I used with the tc-50s....I believe it has more to do with speaker design than electronics....a speaker either has "it" or it doesnt in my opinion

Try smaller sized speakers, or add the medium-sized A-Physics to your list. Also the Genesis line, 501 & up, larger Harbeths, the biggies in the Tannoy TD line.
But, my experience tallies with the above: good placement & electronics do help...

Most single-driver speakers and electrostatics will image very very well, not only on vocals, but on everything else also. As was stated above, the upstream components are very important to this.

Audio Physic Caldera can do it, too. Holographic imaging is one of the strenghts of this speaker. I had them for a couple of years and it was downright scary at times.

Try rewiring the Spica TC-50's with cardas wire and jacks, remove the felt from the front and they open up more but will be brighter.