Hi, thank you for quick response. Usually I cover inner panels of speakers using 10mm felt, it work good to absorb reflection but because the principle operation of the passive radiator is based on the air pressure produced by the woofer. If I understand correctly, if all the internal sides of the speaker are covered with sound-absorbing material, then this reduces the air pressure on the passive radiator and reduces the efficiency of its operation. Please answer if I am wrong and what you recommend that should be done to reduce the loss of air pressure.
How properly covered internal sides of enclosures for speakers with a passive radiator?
My question to people who have practical experience to build a sealed (closed) cabinets for speakers with passive radiator?
I have experience to build speakers with ported cabinets, but now I've decided to build a three-way sealed cabinet using one woofer in the middle of the front panel and one passive radiator below the woofer. When I built the cabinets with ports, to minimize reflection and etc, I put felt material on all interior panels : left, right, rear, bottom and top panels (except the front panel). I know, passive radiator works using air pressure from woofer.