I would have to say LOUDSPEAKERS.
Look at old designs.. hit or miss, basic wood boxes..
Then the Small Thiel parameters came along. then computer work..
So all in all I would give the nod to speakers.
Yes there are great designs from early years.. but those were just luck. Now, even inexpensive speakers can sound really good. Because of all the work that went before.
Though all electronics have also gotten better.. no question. (except maybe some old tube designs.. with updated parts they can still be great.
Look at old designs.. hit or miss, basic wood boxes..
Then the Small Thiel parameters came along. then computer work..
So all in all I would give the nod to speakers.
Yes there are great designs from early years.. but those were just luck. Now, even inexpensive speakers can sound really good. Because of all the work that went before.
Though all electronics have also gotten better.. no question. (except maybe some old tube designs.. with updated parts they can still be great.