So I started going through this thread to try and get my Z1Rs to sound closer to the tuning on my EX1000s and came across this mod.
It WORKS!!!
I experimented with different foams and lengths and ended up with section of real low density which helped curbed the bass from the Z1Rs while also allowing the mids come through better. This mod is good stuff for those who might want less of a V shaped sound out of the Z1Rs.
Now to experiment with cables for this new configuration!
Interesting filter choice. Almost same length as the original but lighter density?