18 SOUND 18-in Next Generation high Performance subwoofer, specifically Designed for high SPL Very Low Frequency Applications in Either a Reflex, bandpass or Horn Loaded Configuration - 18NTLW5000-4 : Amazon.ca: Electronics
Projetos de caixas de som, projetos de amplificadores, dicas de eletrônica - Sombox
Simulation of 21" Bandpass Horn Subwoofer - YouTube