Old School Polk Audio C4 Subwoofer - Four 6x9's in Isobaric Teardrop Enclosure - Member Videos - Host 'em & Post 'em! System Vids / Off Topic - #1 Car Audio Enthusiast
Isobaric loudspeaker - Wikipedia
dual opposing subwoofers vs dual push pull design, thoughts? - Techtalk Speaker Building, Audio, Video Discussion Forum
l three basic types can have many variations including venting the rear chamber, loading the front into a bandpass… | Subwoofer box, Subwoofer box design, Subwoofer