My personal praise in no particular order is first for Peter Walker of Quad, for his revolutionary electrostatic speakers and his contributions to the developement of modern amplifier technology that was and remains as good as a 'straight wire with gain', as he used to put it.
Second to the Philips/Sony team that developed the CD. To add some info about the Philips part of the story, see here:
https://www.philips.com/a-w/research/technologies/cd/beginning.html At the time Philips had a massive physics lab where all kinds of fundamental research were done without too much concern about the immediate benefits. In some ways the Hypex technology is the last fruit of this Philips audio research tradition.
Third, I want to mention the research into speaker design at the BBC, producing not only some memorable designs, but also the methodological groundwork for speaker research, and the launch pad for the Harbeth brand of speakers.
So my list is equaly divided by innovation in electronics and speakers. In those early days amplifiers were not good enough to be transparent, and people like Peter Walker made them become that. Similarly, analogue sources were not really good enough, and the CD changed all that. Ever since, sources and amplifiers can be better than human hearing acuity, so subsequnet innovation can only be about manufacturing technology. Speakers and their interaction with the room remain the weakest link, hence my praise for, again, Peter Walker and for the BBC and Harbeth's Alan Shaw.
However, the list is not complete without a reference to the esthetically and functionally most memorable designs, those by Dieter Rams for Braun.