Choose from the Top Brand Car Audio Subwoofers. We have the best prices & fastest shipping times. SSA® is your #1 source for amplifiers, subwoofers, speakers, tweeters, lithium car audio batteries, AGM batteries and more! Jan 14, 2012 · You wan to tune the box to make the sub play in a certain frequency range the best.. IMO 29-32 hz is awesome for just rap, 33-36 is good for rock rap mix and 37-39 hz for sticky rock.. That's the simplest explanation.. for deep musical bass, you tune the box just above the Fs of the subwoofer. that's where the output of the box will spike and hit hardest. The higher you tune the box, the boomier it'll sound, which isn't audibly pleasing, but tuning around 50Hz does increase SPL.