I find It funny that the ER4XR uses driver tech from the 1920s

[Ambient384]

I gave a historian YouTuber a fright when I told him that modern headphones like the ER4XR use the same driver as the vintage BA radios/speakers he was trying out. Which makes me wonder what BA speakers sound like If they were made today by scaling up the drivers that IEM's use. Seems like the only issue with BA at the time was that It amp tech was to basic to handle the high power needs.