The sub doesn't fully unload until one full octave below tuning. ex. If you have a 30hz box then 15hz it will inload. It is totally safe to play down to 24ish hz with full power. Maybe 22. And it will have good output down to around 24hz, depending on some fators.I wouldn't recommend playing them below tuning in a ported box...
Kind of like more than one 8" in an Integra //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gifAnd two 15's in a Ranger would be insanely loud.