How to improve a small, weak speaker to handle more bass - Quora
DIY 4 x 18" subwoofer - The Paper Horn by Inlow Sound
Amazon.com: Speaker Port Tubes for Bass Enhancer, Subwoofer Air Ports Repalcement & DIY Parts 71mm x 102mm Speaker Cabinet Port Tube, 2-Pack(Black) : Electronics
DIY Audio Projects - Hi-Fi Blog for DIY Audiophiles: Fostex FE167E Bass Reflex Speakers
Assembled Home Audio Rig with 50w+50w STK AMP, Fostex Double Bass Reflex Enclosures. - Team-BHP
15INCH BASSREFLEX MODIFIED PLAN - YouTube
Dayton RS-180 Double Chamber Reflex (DCR)
Amazon.com: Speaker Port Tubes for Bass Enhancer, Subwoofer Air Ports Repalcement & DIY Parts 42.5mm x 80mm Speaker Cabinet Port Tube, 4-Pcs(Black) : Electronics
Cheap Speakers Sound Great In A Proper Enclosure | Hackaday
Fostex DIY Loudspeaker Kits Anyone Can Afford | StereoNET Asia