I was told by people here, that when using jumpers, try using, on one side (pos or neg) the upper one and the other, the lower one. They say it sometimes results in improvement over using both on the lower or higher posts.
I tried it that way, and going with both to the upper posts but it turned out that it sounded best the way the JBL instructs to: using the bass or lower posts. You just have to experiment.
Eventually, I found the best way was to thread the wire through the lower post's eyelet up to the upper one, using just the speaker wire itself. If it's too thick, just make an "S' shape with the wire going around the lower post to the upper post and tighten down the posts.
It's the most coherent sound I ended with.
All the best,
Nonoise
I tried it that way, and going with both to the upper posts but it turned out that it sounded best the way the JBL instructs to: using the bass or lower posts. You just have to experiment.
Eventually, I found the best way was to thread the wire through the lower post's eyelet up to the upper one, using just the speaker wire itself. If it's too thick, just make an "S' shape with the wire going around the lower post to the upper post and tighten down the posts.
It's the most coherent sound I ended with.
All the best,
Nonoise