02-21-2022, 04:29 AM
These are Epos ES14, new they were something like $1100 or $1400/pr in the 1980s and 1990s. I paid $750 used, at a dealer as part of a trade in back in 1999 and then they went into storage for many years. The new tweeters are Peerless Corundum: https://www.parts-express.com/Peerless-D...quantity=2
I'd searched several makers and found it hard to find general specs I wanted. The decision tree sort of went like this:
1) I knew the speakers (as original) were not only nominally 8ohms but that overall they never dipped below 7.2ohms. This is somewhat rare. Most "8ohm" speakers have a dip somewhere in the spectrum, possibly so low that they'll still freak out many amplifiers or make them sound not great by throwing a wrench into making some frequency go wonky.
2) I knew the speakers (as original) had reasonably good efficiency, so that if (worse can) the new tweeter played too loud, a simple resister would fix that. If I'd chosen a low efficiency tweeter, I'd be forced to put a large resister on the woofer and I didn't want to go there.
3) I wanted the flexibility to choose the crossover point. Poor tweeters can't play low. I wanted to be able to cross them low if needed, in case a sophisticated crossover needed to be designed (by someone else, not me.)
The only reason I took this project on is because the original design used one capacitor for a crossover. That's it. The woofer is designed to run full range, rolling off naturally up top. Over the lifespan of these speakers, Epos either used a 3.3 microfarad, or a 2.4 microfarad, or a 2.2 microfarad capacitor on the tweeter. (As the woofer kept getting better with each generation that allowed it to run higher up in its range.) Some owners claim the later ES14 sound worse than the originals but whatever.
I'm using 2.7 microfarad, mostly because of a purchasing mistake, but since this design is now all an experiment, it's a good starting point.
I first tackled the defective tweeter and put on some music. The highs in the speaker were now restored and were not very different in level from the other speaker. And seemed decently matched. Promising! So I swapped out the tweeter in the other one and I gotta say they now sound pretty great, and better than I ever remember. I got very lucky with this, even though my crossover point is likely not ideal.
Original:
(painted ... the veneer wasn't great)
Updated:
Yes the new tweeter overlaps the cabinet frame and woofer frame. Don't care. Yes the tweeter dome is technically too far forward (oh noes, its bad for time alignment). Don't care. It works well. I cleaned up the sawdust around the mounting bolts after that shot was taken.
I'd searched several makers and found it hard to find general specs I wanted. The decision tree sort of went like this:
1) I knew the speakers (as original) were not only nominally 8ohms but that overall they never dipped below 7.2ohms. This is somewhat rare. Most "8ohm" speakers have a dip somewhere in the spectrum, possibly so low that they'll still freak out many amplifiers or make them sound not great by throwing a wrench into making some frequency go wonky.
2) I knew the speakers (as original) had reasonably good efficiency, so that if (worse can) the new tweeter played too loud, a simple resister would fix that. If I'd chosen a low efficiency tweeter, I'd be forced to put a large resister on the woofer and I didn't want to go there.
3) I wanted the flexibility to choose the crossover point. Poor tweeters can't play low. I wanted to be able to cross them low if needed, in case a sophisticated crossover needed to be designed (by someone else, not me.)
The only reason I took this project on is because the original design used one capacitor for a crossover. That's it. The woofer is designed to run full range, rolling off naturally up top. Over the lifespan of these speakers, Epos either used a 3.3 microfarad, or a 2.4 microfarad, or a 2.2 microfarad capacitor on the tweeter. (As the woofer kept getting better with each generation that allowed it to run higher up in its range.) Some owners claim the later ES14 sound worse than the originals but whatever.
I'm using 2.7 microfarad, mostly because of a purchasing mistake, but since this design is now all an experiment, it's a good starting point.
I first tackled the defective tweeter and put on some music. The highs in the speaker were now restored and were not very different in level from the other speaker. And seemed decently matched. Promising! So I swapped out the tweeter in the other one and I gotta say they now sound pretty great, and better than I ever remember. I got very lucky with this, even though my crossover point is likely not ideal.
Original:
(painted ... the veneer wasn't great)
Updated:
Yes the new tweeter overlaps the cabinet frame and woofer frame. Don't care. Yes the tweeter dome is technically too far forward (oh noes, its bad for time alignment). Don't care. It works well. I cleaned up the sawdust around the mounting bolts after that shot was taken.