WOOFERS as PASSIVE RADIATORS | JBL BOOMBOX - YouTube
Amazon.com: Simply Speakers 12 Inch Woofer and Passive Radiator Foam Speaker Repair Kit Compatible with JBL L-150, Fits 9-5/8 Inch Cone, FSK-12Ji (4 Pack) : Electronics
Amazon.com: JBL Flip 6 - Portable Bluetooth Speaker, powerful sound and deep bass, IPX7 waterproof, 12 hours of playtime, JBL PartyBoost for multiple speaker pairing for home, outdoor and travel (Blue) : Electronics