Interesting discussion. There may never be a consensus of what constitutes the best loudspeaker due to psychoacoustics, HRTF and confirmation biases. That said, here’s what we know has and has not changed over time:
What has:
What has:
- materials (drivers, circuits, components, enclosures, damping)
- design technology (CAD -- construction and measurements)
- digital recording and playback (bits)
- room acoustical design and implementation (studio and home)
- anatomical design of the ear (biology)
- vibrational excitement of a medium (how sound is produced)
- wavelengths of audible signals
- unique emotional responses to sound from listeners