When I look at the image below from Speak, I see:
A speaker in a sealed box and a small passive radiator connected to a bigger passive radiator with a rod. Peerless has 10" and 12" passive radiators but there is no 8.5" (12"/(sqrt(2))=8.5") passive radiator availible from them so it's not possible to get a 2:1 area ratio. (that's why I said 3 passive radiators)

Some things are unclear for me:
1. Should the big passive radiator be of the same size as the speaker?
2. Did you build the passive radiators yourself?
3. How did you build the lever?
4. Which speakers/passive radiators/components did you use to build the subwoofer?

Thank you for taking the time to answer my questions. I hope somebody else also will benefit from reading this

• Front lever