I had JSE Model 2's, they measured and sounded the most accurate of any I owned. Whoopie! I drove them with McIntosh SS, 300 wpc. McIntosh SS Preamp.
After a few years, I missed my vintage speakers, extremely efficient, driven by vintage McIntosh tube preamp and more modern Cayin tube amp. They have 2 level controls each (balance mid horn to 15" woofer, balance tweeter to that result, I balance them with SPL and Test Tone CD.
Gotta say, I prefer the vintage horns to the very accurate JSE's. My friend has those JSE's, updated them, he loves them, yet when he listens here, he finds these very involving. Involving has been my criteria once I clearly understood that factor so many years ago.