Looney_Tune 10+ year member
F**k How You Feel
I got a 18 obsidian and want build me a ported instead of the sealed I built now at 4cf. Obsidian recommends using a 6in diameter port for the sub. Im going slot port and found an equation to convert it and got basically 1.5in wide based on my box im going to build...little under 5cf. That seems small to me for an 18 but again im running the rated 600wrms to it because I like my dual alpine pdx setup. Obsidian seems to clearly state u should go by their recommendations...1.5in wide should be fine for port if im running rated 600 to it correct? Gona b tuned to bout 30hz...