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.
JBL used 1’’acoustic fiberglass insulation in their speakers with passive radiators, (except the front baffle). See below: 😎 Mike https://www.lansingheritage.org/html/jbl/plans/1960s-manual.htm https://www.lansingheritage.org/html/jbl/catalogs/1979-home.htm https://www.lansingheritage.org/html/jbl/plans/jbl-plans.htm |
When I use passive radiators, I peel fiberglass in about a 3 to 3 inch sheet and line the box with fiberglass. Remember, anytime you add glass or any type of stuffing, you change the effective box size and how the woofer reacts to that box. Also, a passive radiator, works similarly as a port, as you lengthen a port, you lower its effective tuning frequency, by changing the size and mass of a passive radiator, you are also raising or lowering its effective frequency. |
